linux/kernel/trace/trace_functions.c

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ftrace: function tracer This is a simple trace that uses the ftrace infrastructure. It is designed to be fast and small, and easy to use. It is useful to record things that happen over a very short period of time, and not to analyze the system in general. Updates: available_tracers "function" is added to this file. current_tracer To enable the function tracer: echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer The output of the function_trace file is as follows "echo noverbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst Signed-off-by: Ingo Molnar <mingo@elte.hu> -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / swapper-0 0d.h. 1595128us+: set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper-0 0d.h. 1595131us+: _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) Or with verbose turned on: "echo verbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- swapper 0 0 9 00000000 00000000 [f3675f41] 1595.128ms (+0.003ms): set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper 0 0 9 00000000 00000001 [f3675f45] 1595.131ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) swapper 0 0 9 00000000 00000002 [f3675f48] 1595.135ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) The "trace" file is not affected by the verbose mode, but is by the symonly. echo "nosymonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479967] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <ffffffff80337a4d> <-- _spin_unlock_irqrestore+0xe/0x5a <ffffffff8048cc8f> [ 81.479967] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <ffffffff8048ccbf> <-- sub_preempt_count+0xc/0x7a <ffffffff80233d7b> [ 81.479968] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <ffffffff80233d9f> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> [ 81.479968] CPU 0: bash:3154 vfs_write+0x11d/0x155 <ffffffff8029a043> <-- dnotify_parent+0x12/0x78 <ffffffff802d54fb> [ 81.479968] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <ffffffff802d5516> <-- _spin_lock+0xe/0x70 <ffffffff8048c910> [ 81.479969] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <ffffffff8048c91d> <-- add_preempt_count+0xe/0x77 <ffffffff80233df7> [ 81.479969] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <ffffffff80233e27> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> echo "symonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479913] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <-- _spin_unlock_irqrestore+0xe/0x5a [ 81.479913] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <-- sub_preempt_count+0xc/0x7a [ 81.479913] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <-- in_lock_functions+0x9/0x24 [ 81.479914] CPU 0: bash:3154 vfs_write+0x11d/0x155 <-- dnotify_parent+0x12/0x78 [ 81.479914] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <-- _spin_lock+0xe/0x70 [ 81.479914] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <-- add_preempt_count+0xe/0x77 [ 81.479914] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <-- in_lock_functions+0x9/0x24 Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 19:20:42 +00:00
/*
* ring buffer based function tracer
*
* Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
* Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
*
* Based on code from the latency_tracer, that is:
*
* Copyright (C) 2004-2006 Ingo Molnar
* Copyright (C) 2004 Nadia Yvette Chambers
ftrace: function tracer This is a simple trace that uses the ftrace infrastructure. It is designed to be fast and small, and easy to use. It is useful to record things that happen over a very short period of time, and not to analyze the system in general. Updates: available_tracers "function" is added to this file. current_tracer To enable the function tracer: echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer The output of the function_trace file is as follows "echo noverbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst Signed-off-by: Ingo Molnar <mingo@elte.hu> -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / swapper-0 0d.h. 1595128us+: set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper-0 0d.h. 1595131us+: _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) Or with verbose turned on: "echo verbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- swapper 0 0 9 00000000 00000000 [f3675f41] 1595.128ms (+0.003ms): set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper 0 0 9 00000000 00000001 [f3675f45] 1595.131ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) swapper 0 0 9 00000000 00000002 [f3675f48] 1595.135ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) The "trace" file is not affected by the verbose mode, but is by the symonly. echo "nosymonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479967] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <ffffffff80337a4d> <-- _spin_unlock_irqrestore+0xe/0x5a <ffffffff8048cc8f> [ 81.479967] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <ffffffff8048ccbf> <-- sub_preempt_count+0xc/0x7a <ffffffff80233d7b> [ 81.479968] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <ffffffff80233d9f> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> [ 81.479968] CPU 0: bash:3154 vfs_write+0x11d/0x155 <ffffffff8029a043> <-- dnotify_parent+0x12/0x78 <ffffffff802d54fb> [ 81.479968] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <ffffffff802d5516> <-- _spin_lock+0xe/0x70 <ffffffff8048c910> [ 81.479969] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <ffffffff8048c91d> <-- add_preempt_count+0xe/0x77 <ffffffff80233df7> [ 81.479969] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <ffffffff80233e27> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> echo "symonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479913] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <-- _spin_unlock_irqrestore+0xe/0x5a [ 81.479913] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <-- sub_preempt_count+0xc/0x7a [ 81.479913] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <-- in_lock_functions+0x9/0x24 [ 81.479914] CPU 0: bash:3154 vfs_write+0x11d/0x155 <-- dnotify_parent+0x12/0x78 [ 81.479914] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <-- _spin_lock+0xe/0x70 [ 81.479914] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <-- add_preempt_count+0xe/0x77 [ 81.479914] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <-- in_lock_functions+0x9/0x24 Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 19:20:42 +00:00
*/
#include <linux/ring_buffer.h>
ftrace: function tracer This is a simple trace that uses the ftrace infrastructure. It is designed to be fast and small, and easy to use. It is useful to record things that happen over a very short period of time, and not to analyze the system in general. Updates: available_tracers "function" is added to this file. current_tracer To enable the function tracer: echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer The output of the function_trace file is as follows "echo noverbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst Signed-off-by: Ingo Molnar <mingo@elte.hu> -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / swapper-0 0d.h. 1595128us+: set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper-0 0d.h. 1595131us+: _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) Or with verbose turned on: "echo verbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- swapper 0 0 9 00000000 00000000 [f3675f41] 1595.128ms (+0.003ms): set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper 0 0 9 00000000 00000001 [f3675f45] 1595.131ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) swapper 0 0 9 00000000 00000002 [f3675f48] 1595.135ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) The "trace" file is not affected by the verbose mode, but is by the symonly. echo "nosymonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479967] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <ffffffff80337a4d> <-- _spin_unlock_irqrestore+0xe/0x5a <ffffffff8048cc8f> [ 81.479967] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <ffffffff8048ccbf> <-- sub_preempt_count+0xc/0x7a <ffffffff80233d7b> [ 81.479968] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <ffffffff80233d9f> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> [ 81.479968] CPU 0: bash:3154 vfs_write+0x11d/0x155 <ffffffff8029a043> <-- dnotify_parent+0x12/0x78 <ffffffff802d54fb> [ 81.479968] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <ffffffff802d5516> <-- _spin_lock+0xe/0x70 <ffffffff8048c910> [ 81.479969] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <ffffffff8048c91d> <-- add_preempt_count+0xe/0x77 <ffffffff80233df7> [ 81.479969] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <ffffffff80233e27> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> echo "symonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479913] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <-- _spin_unlock_irqrestore+0xe/0x5a [ 81.479913] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <-- sub_preempt_count+0xc/0x7a [ 81.479913] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <-- in_lock_functions+0x9/0x24 [ 81.479914] CPU 0: bash:3154 vfs_write+0x11d/0x155 <-- dnotify_parent+0x12/0x78 [ 81.479914] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <-- _spin_lock+0xe/0x70 [ 81.479914] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <-- add_preempt_count+0xe/0x77 [ 81.479914] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <-- in_lock_functions+0x9/0x24 Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 19:20:42 +00:00
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/ftrace.h>
#include <linux/slab.h>
#include <linux/fs.h>
ftrace: function tracer This is a simple trace that uses the ftrace infrastructure. It is designed to be fast and small, and easy to use. It is useful to record things that happen over a very short period of time, and not to analyze the system in general. Updates: available_tracers "function" is added to this file. current_tracer To enable the function tracer: echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer The output of the function_trace file is as follows "echo noverbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst Signed-off-by: Ingo Molnar <mingo@elte.hu> -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / swapper-0 0d.h. 1595128us+: set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper-0 0d.h. 1595131us+: _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) Or with verbose turned on: "echo verbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- swapper 0 0 9 00000000 00000000 [f3675f41] 1595.128ms (+0.003ms): set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper 0 0 9 00000000 00000001 [f3675f45] 1595.131ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) swapper 0 0 9 00000000 00000002 [f3675f48] 1595.135ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) The "trace" file is not affected by the verbose mode, but is by the symonly. echo "nosymonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479967] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <ffffffff80337a4d> <-- _spin_unlock_irqrestore+0xe/0x5a <ffffffff8048cc8f> [ 81.479967] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <ffffffff8048ccbf> <-- sub_preempt_count+0xc/0x7a <ffffffff80233d7b> [ 81.479968] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <ffffffff80233d9f> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> [ 81.479968] CPU 0: bash:3154 vfs_write+0x11d/0x155 <ffffffff8029a043> <-- dnotify_parent+0x12/0x78 <ffffffff802d54fb> [ 81.479968] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <ffffffff802d5516> <-- _spin_lock+0xe/0x70 <ffffffff8048c910> [ 81.479969] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <ffffffff8048c91d> <-- add_preempt_count+0xe/0x77 <ffffffff80233df7> [ 81.479969] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <ffffffff80233e27> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> echo "symonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479913] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <-- _spin_unlock_irqrestore+0xe/0x5a [ 81.479913] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <-- sub_preempt_count+0xc/0x7a [ 81.479913] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <-- in_lock_functions+0x9/0x24 [ 81.479914] CPU 0: bash:3154 vfs_write+0x11d/0x155 <-- dnotify_parent+0x12/0x78 [ 81.479914] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <-- _spin_lock+0xe/0x70 [ 81.479914] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <-- add_preempt_count+0xe/0x77 [ 81.479914] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <-- in_lock_functions+0x9/0x24 Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 19:20:42 +00:00
#include "trace.h"
static void tracing_start_function_trace(struct trace_array *tr);
static void tracing_stop_function_trace(struct trace_array *tr);
static void
function_trace_call(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *pt_regs);
static void
function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *pt_regs);
static struct tracer_flags func_flags;
/* Our option */
enum {
TRACE_FUNC_OPT_STACK = 0x1,
};
static int allocate_ftrace_ops(struct trace_array *tr)
{
struct ftrace_ops *ops;
ops = kzalloc(sizeof(*ops), GFP_KERNEL);
if (!ops)
return -ENOMEM;
/* Currently only the non stack verision is supported */
ops->func = function_trace_call;
ops->flags = FTRACE_OPS_FL_RECURSION_SAFE;
tr->ops = ops;
ops->private = tr;
return 0;
}
int ftrace_create_function_files(struct trace_array *tr,
struct dentry *parent)
{
int ret;
/*
* The top level array uses the "global_ops", and the files are
* created on boot up.
*/
if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
return 0;
ret = allocate_ftrace_ops(tr);
if (ret)
return ret;
ftrace_create_filter_files(tr->ops, parent);
return 0;
}
void ftrace_destroy_function_files(struct trace_array *tr)
{
ftrace_destroy_filter_files(tr->ops);
kfree(tr->ops);
tr->ops = NULL;
}
static int function_trace_init(struct trace_array *tr)
ftrace: function tracer This is a simple trace that uses the ftrace infrastructure. It is designed to be fast and small, and easy to use. It is useful to record things that happen over a very short period of time, and not to analyze the system in general. Updates: available_tracers "function" is added to this file. current_tracer To enable the function tracer: echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer The output of the function_trace file is as follows "echo noverbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst Signed-off-by: Ingo Molnar <mingo@elte.hu> -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / swapper-0 0d.h. 1595128us+: set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper-0 0d.h. 1595131us+: _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) Or with verbose turned on: "echo verbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- swapper 0 0 9 00000000 00000000 [f3675f41] 1595.128ms (+0.003ms): set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper 0 0 9 00000000 00000001 [f3675f45] 1595.131ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) swapper 0 0 9 00000000 00000002 [f3675f48] 1595.135ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) The "trace" file is not affected by the verbose mode, but is by the symonly. echo "nosymonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479967] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <ffffffff80337a4d> <-- _spin_unlock_irqrestore+0xe/0x5a <ffffffff8048cc8f> [ 81.479967] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <ffffffff8048ccbf> <-- sub_preempt_count+0xc/0x7a <ffffffff80233d7b> [ 81.479968] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <ffffffff80233d9f> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> [ 81.479968] CPU 0: bash:3154 vfs_write+0x11d/0x155 <ffffffff8029a043> <-- dnotify_parent+0x12/0x78 <ffffffff802d54fb> [ 81.479968] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <ffffffff802d5516> <-- _spin_lock+0xe/0x70 <ffffffff8048c910> [ 81.479969] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <ffffffff8048c91d> <-- add_preempt_count+0xe/0x77 <ffffffff80233df7> [ 81.479969] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <ffffffff80233e27> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> echo "symonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479913] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <-- _spin_unlock_irqrestore+0xe/0x5a [ 81.479913] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <-- sub_preempt_count+0xc/0x7a [ 81.479913] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <-- in_lock_functions+0x9/0x24 [ 81.479914] CPU 0: bash:3154 vfs_write+0x11d/0x155 <-- dnotify_parent+0x12/0x78 [ 81.479914] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <-- _spin_lock+0xe/0x70 [ 81.479914] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <-- add_preempt_count+0xe/0x77 [ 81.479914] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <-- in_lock_functions+0x9/0x24 Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 19:20:42 +00:00
{
ftrace_func_t func;
/*
* Instance trace_arrays get their ops allocated
* at instance creation. Unless it failed
* the allocation.
*/
if (!tr->ops)
return -ENOMEM;
/* Currently only the global instance can do stack tracing */
if (tr->flags & TRACE_ARRAY_FL_GLOBAL &&
func_flags.val & TRACE_FUNC_OPT_STACK)
func = function_stack_trace_call;
else
func = function_trace_call;
ftrace_init_array_ops(tr, func);
tr->trace_buffer.cpu = get_cpu();
put_cpu();
tracing_start_cmdline_record();
tracing_start_function_trace(tr);
return 0;
ftrace: function tracer This is a simple trace that uses the ftrace infrastructure. It is designed to be fast and small, and easy to use. It is useful to record things that happen over a very short period of time, and not to analyze the system in general. Updates: available_tracers "function" is added to this file. current_tracer To enable the function tracer: echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer The output of the function_trace file is as follows "echo noverbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst Signed-off-by: Ingo Molnar <mingo@elte.hu> -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / swapper-0 0d.h. 1595128us+: set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper-0 0d.h. 1595131us+: _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) Or with verbose turned on: "echo verbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- swapper 0 0 9 00000000 00000000 [f3675f41] 1595.128ms (+0.003ms): set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper 0 0 9 00000000 00000001 [f3675f45] 1595.131ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) swapper 0 0 9 00000000 00000002 [f3675f48] 1595.135ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) The "trace" file is not affected by the verbose mode, but is by the symonly. echo "nosymonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479967] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <ffffffff80337a4d> <-- _spin_unlock_irqrestore+0xe/0x5a <ffffffff8048cc8f> [ 81.479967] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <ffffffff8048ccbf> <-- sub_preempt_count+0xc/0x7a <ffffffff80233d7b> [ 81.479968] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <ffffffff80233d9f> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> [ 81.479968] CPU 0: bash:3154 vfs_write+0x11d/0x155 <ffffffff8029a043> <-- dnotify_parent+0x12/0x78 <ffffffff802d54fb> [ 81.479968] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <ffffffff802d5516> <-- _spin_lock+0xe/0x70 <ffffffff8048c910> [ 81.479969] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <ffffffff8048c91d> <-- add_preempt_count+0xe/0x77 <ffffffff80233df7> [ 81.479969] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <ffffffff80233e27> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> echo "symonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479913] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <-- _spin_unlock_irqrestore+0xe/0x5a [ 81.479913] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <-- sub_preempt_count+0xc/0x7a [ 81.479913] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <-- in_lock_functions+0x9/0x24 [ 81.479914] CPU 0: bash:3154 vfs_write+0x11d/0x155 <-- dnotify_parent+0x12/0x78 [ 81.479914] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <-- _spin_lock+0xe/0x70 [ 81.479914] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <-- add_preempt_count+0xe/0x77 [ 81.479914] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <-- in_lock_functions+0x9/0x24 Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 19:20:42 +00:00
}
static void function_trace_reset(struct trace_array *tr)
ftrace: function tracer This is a simple trace that uses the ftrace infrastructure. It is designed to be fast and small, and easy to use. It is useful to record things that happen over a very short period of time, and not to analyze the system in general. Updates: available_tracers "function" is added to this file. current_tracer To enable the function tracer: echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer The output of the function_trace file is as follows "echo noverbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst Signed-off-by: Ingo Molnar <mingo@elte.hu> -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / swapper-0 0d.h. 1595128us+: set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper-0 0d.h. 1595131us+: _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) Or with verbose turned on: "echo verbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- swapper 0 0 9 00000000 00000000 [f3675f41] 1595.128ms (+0.003ms): set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper 0 0 9 00000000 00000001 [f3675f45] 1595.131ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) swapper 0 0 9 00000000 00000002 [f3675f48] 1595.135ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) The "trace" file is not affected by the verbose mode, but is by the symonly. echo "nosymonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479967] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <ffffffff80337a4d> <-- _spin_unlock_irqrestore+0xe/0x5a <ffffffff8048cc8f> [ 81.479967] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <ffffffff8048ccbf> <-- sub_preempt_count+0xc/0x7a <ffffffff80233d7b> [ 81.479968] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <ffffffff80233d9f> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> [ 81.479968] CPU 0: bash:3154 vfs_write+0x11d/0x155 <ffffffff8029a043> <-- dnotify_parent+0x12/0x78 <ffffffff802d54fb> [ 81.479968] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <ffffffff802d5516> <-- _spin_lock+0xe/0x70 <ffffffff8048c910> [ 81.479969] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <ffffffff8048c91d> <-- add_preempt_count+0xe/0x77 <ffffffff80233df7> [ 81.479969] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <ffffffff80233e27> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> echo "symonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479913] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <-- _spin_unlock_irqrestore+0xe/0x5a [ 81.479913] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <-- sub_preempt_count+0xc/0x7a [ 81.479913] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <-- in_lock_functions+0x9/0x24 [ 81.479914] CPU 0: bash:3154 vfs_write+0x11d/0x155 <-- dnotify_parent+0x12/0x78 [ 81.479914] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <-- _spin_lock+0xe/0x70 [ 81.479914] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <-- add_preempt_count+0xe/0x77 [ 81.479914] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <-- in_lock_functions+0x9/0x24 Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 19:20:42 +00:00
{
tracing_stop_function_trace(tr);
tracing_stop_cmdline_record();
ftrace_reset_array_ops(tr);
ftrace: function tracer This is a simple trace that uses the ftrace infrastructure. It is designed to be fast and small, and easy to use. It is useful to record things that happen over a very short period of time, and not to analyze the system in general. Updates: available_tracers "function" is added to this file. current_tracer To enable the function tracer: echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer The output of the function_trace file is as follows "echo noverbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst Signed-off-by: Ingo Molnar <mingo@elte.hu> -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / swapper-0 0d.h. 1595128us+: set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper-0 0d.h. 1595131us+: _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) Or with verbose turned on: "echo verbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- swapper 0 0 9 00000000 00000000 [f3675f41] 1595.128ms (+0.003ms): set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper 0 0 9 00000000 00000001 [f3675f45] 1595.131ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) swapper 0 0 9 00000000 00000002 [f3675f48] 1595.135ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) The "trace" file is not affected by the verbose mode, but is by the symonly. echo "nosymonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479967] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <ffffffff80337a4d> <-- _spin_unlock_irqrestore+0xe/0x5a <ffffffff8048cc8f> [ 81.479967] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <ffffffff8048ccbf> <-- sub_preempt_count+0xc/0x7a <ffffffff80233d7b> [ 81.479968] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <ffffffff80233d9f> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> [ 81.479968] CPU 0: bash:3154 vfs_write+0x11d/0x155 <ffffffff8029a043> <-- dnotify_parent+0x12/0x78 <ffffffff802d54fb> [ 81.479968] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <ffffffff802d5516> <-- _spin_lock+0xe/0x70 <ffffffff8048c910> [ 81.479969] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <ffffffff8048c91d> <-- add_preempt_count+0xe/0x77 <ffffffff80233df7> [ 81.479969] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <ffffffff80233e27> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> echo "symonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479913] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <-- _spin_unlock_irqrestore+0xe/0x5a [ 81.479913] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <-- sub_preempt_count+0xc/0x7a [ 81.479913] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <-- in_lock_functions+0x9/0x24 [ 81.479914] CPU 0: bash:3154 vfs_write+0x11d/0x155 <-- dnotify_parent+0x12/0x78 [ 81.479914] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <-- _spin_lock+0xe/0x70 [ 81.479914] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <-- add_preempt_count+0xe/0x77 [ 81.479914] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <-- in_lock_functions+0x9/0x24 Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 19:20:42 +00:00
}
ftrace: restructure tracing start/stop infrastructure Impact: change where tracing is started up and stopped Currently, when a new tracer is selected via echo'ing a tracer name into the current_tracer file, the startup is only done if tracing_enabled is set to one. If tracing_enabled is changed to zero (by echo'ing 0 into the tracing_enabled file) a full shutdown is performed. The full startup and shutdown of a tracer can be expensive and the user can lose out traces when echo'ing in 0 to the tracing_enabled file, because the process takes too long. There can also be places that the user would like to start and stop the tracer several times and doing the full startup and shutdown of a tracer might be too expensive. This patch performs the full startup and shutdown when a tracer is selected. It also adds a way to do a quick start or stop of a tracer. The quick version is just a flag that prevents the tracing from taking place, but the overhead of the code is still there. For example, the startup of a tracer may enable tracepoints, or enable the function tracer. The stop and start will just set a flag to have the tracer ignore the calls when the tracepoint or function trace is called. The overhead of the tracer may still be present when the tracer is stopped, but no tracing will occur. Setting the tracer to the 'nop' tracer (or any other tracer) will perform the shutdown of the tracer which will disable the tracepoint or disable the function tracer. The tracing_enabled file will simply start or stop tracing. This change is all internal. The end result for the user should be the same as before. If tracing_enabled is not set, no trace will happen. If tracing_enabled is set, then the trace will happen. The tracing_enabled variable is static between tracers. Enabling tracing_enabled and going to another tracer will keep tracing_enabled enabled. Same is true with disabling tracing_enabled. This patch will now provide a fast start/stop method to the users for enabling or disabling tracing. Note: There were two methods to the struct tracer that were never used: The methods start and stop. These were to be used as a hook to the reading of the trace output, but ended up not being necessary. These two methods are now used to enable the start and stop of each tracer, in case the tracer needs to do more than just not write into the buffer. For example, the irqsoff tracer must stop recording max latencies when tracing is stopped. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-05 21:05:44 +00:00
static void function_trace_start(struct trace_array *tr)
{
tracing_reset_online_cpus(&tr->trace_buffer);
ftrace: restructure tracing start/stop infrastructure Impact: change where tracing is started up and stopped Currently, when a new tracer is selected via echo'ing a tracer name into the current_tracer file, the startup is only done if tracing_enabled is set to one. If tracing_enabled is changed to zero (by echo'ing 0 into the tracing_enabled file) a full shutdown is performed. The full startup and shutdown of a tracer can be expensive and the user can lose out traces when echo'ing in 0 to the tracing_enabled file, because the process takes too long. There can also be places that the user would like to start and stop the tracer several times and doing the full startup and shutdown of a tracer might be too expensive. This patch performs the full startup and shutdown when a tracer is selected. It also adds a way to do a quick start or stop of a tracer. The quick version is just a flag that prevents the tracing from taking place, but the overhead of the code is still there. For example, the startup of a tracer may enable tracepoints, or enable the function tracer. The stop and start will just set a flag to have the tracer ignore the calls when the tracepoint or function trace is called. The overhead of the tracer may still be present when the tracer is stopped, but no tracing will occur. Setting the tracer to the 'nop' tracer (or any other tracer) will perform the shutdown of the tracer which will disable the tracepoint or disable the function tracer. The tracing_enabled file will simply start or stop tracing. This change is all internal. The end result for the user should be the same as before. If tracing_enabled is not set, no trace will happen. If tracing_enabled is set, then the trace will happen. The tracing_enabled variable is static between tracers. Enabling tracing_enabled and going to another tracer will keep tracing_enabled enabled. Same is true with disabling tracing_enabled. This patch will now provide a fast start/stop method to the users for enabling or disabling tracing. Note: There were two methods to the struct tracer that were never used: The methods start and stop. These were to be used as a hook to the reading of the trace output, but ended up not being necessary. These two methods are now used to enable the start and stop of each tracer, in case the tracer needs to do more than just not write into the buffer. For example, the irqsoff tracer must stop recording max latencies when tracing is stopped. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-05 21:05:44 +00:00
}
static void
function_trace_call(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *pt_regs)
{
struct trace_array *tr = op->private;
struct trace_array_cpu *data;
unsigned long flags;
int bit;
int cpu;
int pc;
if (unlikely(!tr->function_enabled))
return;
ftrace: Use only the preempt version of function tracing The function tracer had two different versions of function tracing. The disabling of irqs version and the preempt disable version. As function tracing in very intrusive and can cause nasty recursion issues, it has its own recursion protection. But the old method to do this was a flat layer. If it detected that a recursion was happening then it would just return without recording. This made the preempt version (much faster than the irq disabling one) not very useful, because if an interrupt were to occur after the recursion flag was set, the interrupt would not be traced at all, because every function that was traced would think it recursed on itself (due to the context it preempted setting the recursive flag). Now that we have a recursion flag for every context level, we no longer need to worry about that. We can disable preemption, set the current context recursion check bit, and go on. If an interrupt were to come along, it would check its own context bit and happily continue to trace. As the preempt version is faster than the irq disable version, there's no more reason to keep the preempt version around. And the irq disable version still had an issue with missing out on tracing NMI code. Remove the irq disable function tracer version and have the preempt disable version be the default (and only version). Before this patch we had from running: # echo function > /debug/tracing/current_tracer # for i in `seq 10`; do ./hackbench 50; done Time: 12.028 Time: 11.945 Time: 11.925 Time: 11.964 Time: 12.002 Time: 11.910 Time: 11.944 Time: 11.929 Time: 11.941 Time: 11.924 (average: 11.9512) Now we have: # echo function > /debug/tracing/current_tracer # for i in `seq 10`; do ./hackbench 50; done Time: 10.285 Time: 10.407 Time: 10.243 Time: 10.372 Time: 10.380 Time: 10.198 Time: 10.272 Time: 10.354 Time: 10.248 Time: 10.253 (average: 10.3012) a 13.8% savings! Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-11-02 21:52:35 +00:00
pc = preempt_count();
preempt_disable_notrace();
ftrace: Use only the preempt version of function tracing The function tracer had two different versions of function tracing. The disabling of irqs version and the preempt disable version. As function tracing in very intrusive and can cause nasty recursion issues, it has its own recursion protection. But the old method to do this was a flat layer. If it detected that a recursion was happening then it would just return without recording. This made the preempt version (much faster than the irq disabling one) not very useful, because if an interrupt were to occur after the recursion flag was set, the interrupt would not be traced at all, because every function that was traced would think it recursed on itself (due to the context it preempted setting the recursive flag). Now that we have a recursion flag for every context level, we no longer need to worry about that. We can disable preemption, set the current context recursion check bit, and go on. If an interrupt were to come along, it would check its own context bit and happily continue to trace. As the preempt version is faster than the irq disable version, there's no more reason to keep the preempt version around. And the irq disable version still had an issue with missing out on tracing NMI code. Remove the irq disable function tracer version and have the preempt disable version be the default (and only version). Before this patch we had from running: # echo function > /debug/tracing/current_tracer # for i in `seq 10`; do ./hackbench 50; done Time: 12.028 Time: 11.945 Time: 11.925 Time: 11.964 Time: 12.002 Time: 11.910 Time: 11.944 Time: 11.929 Time: 11.941 Time: 11.924 (average: 11.9512) Now we have: # echo function > /debug/tracing/current_tracer # for i in `seq 10`; do ./hackbench 50; done Time: 10.285 Time: 10.407 Time: 10.243 Time: 10.372 Time: 10.380 Time: 10.198 Time: 10.272 Time: 10.354 Time: 10.248 Time: 10.253 (average: 10.3012) a 13.8% savings! Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-11-02 21:52:35 +00:00
bit = trace_test_and_set_recursion(TRACE_FTRACE_START, TRACE_FTRACE_MAX);
if (bit < 0)
goto out;
cpu = smp_processor_id();
data = per_cpu_ptr(tr->trace_buffer.data, cpu);
ftrace: Use only the preempt version of function tracing The function tracer had two different versions of function tracing. The disabling of irqs version and the preempt disable version. As function tracing in very intrusive and can cause nasty recursion issues, it has its own recursion protection. But the old method to do this was a flat layer. If it detected that a recursion was happening then it would just return without recording. This made the preempt version (much faster than the irq disabling one) not very useful, because if an interrupt were to occur after the recursion flag was set, the interrupt would not be traced at all, because every function that was traced would think it recursed on itself (due to the context it preempted setting the recursive flag). Now that we have a recursion flag for every context level, we no longer need to worry about that. We can disable preemption, set the current context recursion check bit, and go on. If an interrupt were to come along, it would check its own context bit and happily continue to trace. As the preempt version is faster than the irq disable version, there's no more reason to keep the preempt version around. And the irq disable version still had an issue with missing out on tracing NMI code. Remove the irq disable function tracer version and have the preempt disable version be the default (and only version). Before this patch we had from running: # echo function > /debug/tracing/current_tracer # for i in `seq 10`; do ./hackbench 50; done Time: 12.028 Time: 11.945 Time: 11.925 Time: 11.964 Time: 12.002 Time: 11.910 Time: 11.944 Time: 11.929 Time: 11.941 Time: 11.924 (average: 11.9512) Now we have: # echo function > /debug/tracing/current_tracer # for i in `seq 10`; do ./hackbench 50; done Time: 10.285 Time: 10.407 Time: 10.243 Time: 10.372 Time: 10.380 Time: 10.198 Time: 10.272 Time: 10.354 Time: 10.248 Time: 10.253 (average: 10.3012) a 13.8% savings! Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-11-02 21:52:35 +00:00
if (!atomic_read(&data->disabled)) {
local_save_flags(flags);
trace_function(tr, ip, parent_ip, flags, pc);
}
ftrace: Use only the preempt version of function tracing The function tracer had two different versions of function tracing. The disabling of irqs version and the preempt disable version. As function tracing in very intrusive and can cause nasty recursion issues, it has its own recursion protection. But the old method to do this was a flat layer. If it detected that a recursion was happening then it would just return without recording. This made the preempt version (much faster than the irq disabling one) not very useful, because if an interrupt were to occur after the recursion flag was set, the interrupt would not be traced at all, because every function that was traced would think it recursed on itself (due to the context it preempted setting the recursive flag). Now that we have a recursion flag for every context level, we no longer need to worry about that. We can disable preemption, set the current context recursion check bit, and go on. If an interrupt were to come along, it would check its own context bit and happily continue to trace. As the preempt version is faster than the irq disable version, there's no more reason to keep the preempt version around. And the irq disable version still had an issue with missing out on tracing NMI code. Remove the irq disable function tracer version and have the preempt disable version be the default (and only version). Before this patch we had from running: # echo function > /debug/tracing/current_tracer # for i in `seq 10`; do ./hackbench 50; done Time: 12.028 Time: 11.945 Time: 11.925 Time: 11.964 Time: 12.002 Time: 11.910 Time: 11.944 Time: 11.929 Time: 11.941 Time: 11.924 (average: 11.9512) Now we have: # echo function > /debug/tracing/current_tracer # for i in `seq 10`; do ./hackbench 50; done Time: 10.285 Time: 10.407 Time: 10.243 Time: 10.372 Time: 10.380 Time: 10.198 Time: 10.272 Time: 10.354 Time: 10.248 Time: 10.253 (average: 10.3012) a 13.8% savings! Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-11-02 21:52:35 +00:00
trace_clear_recursion(bit);
ftrace: Use only the preempt version of function tracing The function tracer had two different versions of function tracing. The disabling of irqs version and the preempt disable version. As function tracing in very intrusive and can cause nasty recursion issues, it has its own recursion protection. But the old method to do this was a flat layer. If it detected that a recursion was happening then it would just return without recording. This made the preempt version (much faster than the irq disabling one) not very useful, because if an interrupt were to occur after the recursion flag was set, the interrupt would not be traced at all, because every function that was traced would think it recursed on itself (due to the context it preempted setting the recursive flag). Now that we have a recursion flag for every context level, we no longer need to worry about that. We can disable preemption, set the current context recursion check bit, and go on. If an interrupt were to come along, it would check its own context bit and happily continue to trace. As the preempt version is faster than the irq disable version, there's no more reason to keep the preempt version around. And the irq disable version still had an issue with missing out on tracing NMI code. Remove the irq disable function tracer version and have the preempt disable version be the default (and only version). Before this patch we had from running: # echo function > /debug/tracing/current_tracer # for i in `seq 10`; do ./hackbench 50; done Time: 12.028 Time: 11.945 Time: 11.925 Time: 11.964 Time: 12.002 Time: 11.910 Time: 11.944 Time: 11.929 Time: 11.941 Time: 11.924 (average: 11.9512) Now we have: # echo function > /debug/tracing/current_tracer # for i in `seq 10`; do ./hackbench 50; done Time: 10.285 Time: 10.407 Time: 10.243 Time: 10.372 Time: 10.380 Time: 10.198 Time: 10.272 Time: 10.354 Time: 10.248 Time: 10.253 (average: 10.3012) a 13.8% savings! Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-11-02 21:52:35 +00:00
out:
preempt_enable_notrace();
}
static void
function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *pt_regs)
{
struct trace_array *tr = op->private;
struct trace_array_cpu *data;
unsigned long flags;
long disabled;
int cpu;
int pc;
if (unlikely(!tr->function_enabled))
return;
/*
* Need to use raw, since this must be called before the
* recursive protection is performed.
*/
local_irq_save(flags);
cpu = raw_smp_processor_id();
data = per_cpu_ptr(tr->trace_buffer.data, cpu);
disabled = atomic_inc_return(&data->disabled);
if (likely(disabled == 1)) {
pc = preempt_count();
trace_function(tr, ip, parent_ip, flags, pc);
/*
* skip over 5 funcs:
* __ftrace_trace_stack,
* __trace_stack,
* function_stack_trace_call
* ftrace_list_func
* ftrace_call
*/
__trace_stack(tr, flags, 5, pc);
}
atomic_dec(&data->disabled);
local_irq_restore(flags);
}
static struct tracer_opt func_opts[] = {
#ifdef CONFIG_STACKTRACE
{ TRACER_OPT(func_stack_trace, TRACE_FUNC_OPT_STACK) },
#endif
{ } /* Always set a last empty entry */
};
static struct tracer_flags func_flags = {
.val = 0, /* By default: all flags disabled */
.opts = func_opts
};
static void tracing_start_function_trace(struct trace_array *tr)
{
tr->function_enabled = 0;
register_ftrace_function(tr->ops);
tr->function_enabled = 1;
}
static void tracing_stop_function_trace(struct trace_array *tr)
{
tr->function_enabled = 0;
unregister_ftrace_function(tr->ops);
}
static int
func_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
{
switch (bit) {
case TRACE_FUNC_OPT_STACK:
/* do nothing if already set */
if (!!set == !!(func_flags.val & TRACE_FUNC_OPT_STACK))
break;
unregister_ftrace_function(tr->ops);
if (set) {
tr->ops->func = function_stack_trace_call;
register_ftrace_function(tr->ops);
} else {
tr->ops->func = function_trace_call;
register_ftrace_function(tr->ops);
}
break;
default:
return -EINVAL;
}
return 0;
}
static struct tracer function_trace __tracer_data =
ftrace: function tracer This is a simple trace that uses the ftrace infrastructure. It is designed to be fast and small, and easy to use. It is useful to record things that happen over a very short period of time, and not to analyze the system in general. Updates: available_tracers "function" is added to this file. current_tracer To enable the function tracer: echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer The output of the function_trace file is as follows "echo noverbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst Signed-off-by: Ingo Molnar <mingo@elte.hu> -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / swapper-0 0d.h. 1595128us+: set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper-0 0d.h. 1595131us+: _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) Or with verbose turned on: "echo verbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- swapper 0 0 9 00000000 00000000 [f3675f41] 1595.128ms (+0.003ms): set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper 0 0 9 00000000 00000001 [f3675f45] 1595.131ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) swapper 0 0 9 00000000 00000002 [f3675f48] 1595.135ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) The "trace" file is not affected by the verbose mode, but is by the symonly. echo "nosymonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479967] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <ffffffff80337a4d> <-- _spin_unlock_irqrestore+0xe/0x5a <ffffffff8048cc8f> [ 81.479967] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <ffffffff8048ccbf> <-- sub_preempt_count+0xc/0x7a <ffffffff80233d7b> [ 81.479968] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <ffffffff80233d9f> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> [ 81.479968] CPU 0: bash:3154 vfs_write+0x11d/0x155 <ffffffff8029a043> <-- dnotify_parent+0x12/0x78 <ffffffff802d54fb> [ 81.479968] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <ffffffff802d5516> <-- _spin_lock+0xe/0x70 <ffffffff8048c910> [ 81.479969] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <ffffffff8048c91d> <-- add_preempt_count+0xe/0x77 <ffffffff80233df7> [ 81.479969] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <ffffffff80233e27> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> echo "symonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479913] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <-- _spin_unlock_irqrestore+0xe/0x5a [ 81.479913] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <-- sub_preempt_count+0xc/0x7a [ 81.479913] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <-- in_lock_functions+0x9/0x24 [ 81.479914] CPU 0: bash:3154 vfs_write+0x11d/0x155 <-- dnotify_parent+0x12/0x78 [ 81.479914] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <-- _spin_lock+0xe/0x70 [ 81.479914] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <-- add_preempt_count+0xe/0x77 [ 81.479914] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <-- in_lock_functions+0x9/0x24 Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 19:20:42 +00:00
{
.name = "function",
.init = function_trace_init,
.reset = function_trace_reset,
.start = function_trace_start,
.flags = &func_flags,
.set_flag = func_set_flag,
.allow_instances = true,
#ifdef CONFIG_FTRACE_SELFTEST
.selftest = trace_selftest_startup_function,
#endif
ftrace: function tracer This is a simple trace that uses the ftrace infrastructure. It is designed to be fast and small, and easy to use. It is useful to record things that happen over a very short period of time, and not to analyze the system in general. Updates: available_tracers "function" is added to this file. current_tracer To enable the function tracer: echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer The output of the function_trace file is as follows "echo noverbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst Signed-off-by: Ingo Molnar <mingo@elte.hu> -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / swapper-0 0d.h. 1595128us+: set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper-0 0d.h. 1595131us+: _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) Or with verbose turned on: "echo verbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- swapper 0 0 9 00000000 00000000 [f3675f41] 1595.128ms (+0.003ms): set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper 0 0 9 00000000 00000001 [f3675f45] 1595.131ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) swapper 0 0 9 00000000 00000002 [f3675f48] 1595.135ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) The "trace" file is not affected by the verbose mode, but is by the symonly. echo "nosymonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479967] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <ffffffff80337a4d> <-- _spin_unlock_irqrestore+0xe/0x5a <ffffffff8048cc8f> [ 81.479967] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <ffffffff8048ccbf> <-- sub_preempt_count+0xc/0x7a <ffffffff80233d7b> [ 81.479968] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <ffffffff80233d9f> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> [ 81.479968] CPU 0: bash:3154 vfs_write+0x11d/0x155 <ffffffff8029a043> <-- dnotify_parent+0x12/0x78 <ffffffff802d54fb> [ 81.479968] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <ffffffff802d5516> <-- _spin_lock+0xe/0x70 <ffffffff8048c910> [ 81.479969] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <ffffffff8048c91d> <-- add_preempt_count+0xe/0x77 <ffffffff80233df7> [ 81.479969] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <ffffffff80233e27> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> echo "symonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479913] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <-- _spin_unlock_irqrestore+0xe/0x5a [ 81.479913] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <-- sub_preempt_count+0xc/0x7a [ 81.479913] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <-- in_lock_functions+0x9/0x24 [ 81.479914] CPU 0: bash:3154 vfs_write+0x11d/0x155 <-- dnotify_parent+0x12/0x78 [ 81.479914] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <-- _spin_lock+0xe/0x70 [ 81.479914] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <-- add_preempt_count+0xe/0x77 [ 81.479914] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <-- in_lock_functions+0x9/0x24 Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 19:20:42 +00:00
};
#ifdef CONFIG_DYNAMIC_FTRACE
static void update_traceon_count(void **data, bool on)
{
tracing: Fix race of function probes counting The function probe counting for traceon and traceoff suffered a race condition where if the probe was executing on two or more CPUs at the same time, it could decrement the counter by more than one when disabling (or enabling) the tracer only once. The way the traceon and traceoff probes are suppose to work is that they disable (or enable) tracing once per count. If a user were to echo 'schedule:traceoff:3' into set_ftrace_filter, then when the schedule function was called, it would disable tracing. But the count should only be decremented once (to 2). Then if the user enabled tracing again (via tracing_on file), the next call to schedule would disable tracing again and the count would be decremented to 1. But if multiple CPUS called schedule at the same time, it is possible that the count would be decremented more than once because of the simple "count--" used. By reading the count into a local variable and using memory barriers we can guarantee that the count would only be decremented once per disable (or enable). The stack trace probe had a similar race, but here the stack trace will decrement for each time it is called. But this had the read-modify- write race, where it could stack trace more than the number of times that was specified. This case we use a cmpxchg to stack trace only the number of times specified. The dump probes can still use the old "update_count()" function as they only run once, and that is controlled by the dump logic itself. Link: http://lkml.kernel.org/r/20141118134643.4b550ee4@gandalf.local.home Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-11-18 04:08:24 +00:00
long *count = (long *)data;
long old_count = *count;
tracing: Fix race of function probes counting The function probe counting for traceon and traceoff suffered a race condition where if the probe was executing on two or more CPUs at the same time, it could decrement the counter by more than one when disabling (or enabling) the tracer only once. The way the traceon and traceoff probes are suppose to work is that they disable (or enable) tracing once per count. If a user were to echo 'schedule:traceoff:3' into set_ftrace_filter, then when the schedule function was called, it would disable tracing. But the count should only be decremented once (to 2). Then if the user enabled tracing again (via tracing_on file), the next call to schedule would disable tracing again and the count would be decremented to 1. But if multiple CPUS called schedule at the same time, it is possible that the count would be decremented more than once because of the simple "count--" used. By reading the count into a local variable and using memory barriers we can guarantee that the count would only be decremented once per disable (or enable). The stack trace probe had a similar race, but here the stack trace will decrement for each time it is called. But this had the read-modify- write race, where it could stack trace more than the number of times that was specified. This case we use a cmpxchg to stack trace only the number of times specified. The dump probes can still use the old "update_count()" function as they only run once, and that is controlled by the dump logic itself. Link: http://lkml.kernel.org/r/20141118134643.4b550ee4@gandalf.local.home Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-11-18 04:08:24 +00:00
/*
* Tracing gets disabled (or enabled) once per count.
* This function can be called at the same time on multiple CPUs.
tracing: Fix race of function probes counting The function probe counting for traceon and traceoff suffered a race condition where if the probe was executing on two or more CPUs at the same time, it could decrement the counter by more than one when disabling (or enabling) the tracer only once. The way the traceon and traceoff probes are suppose to work is that they disable (or enable) tracing once per count. If a user were to echo 'schedule:traceoff:3' into set_ftrace_filter, then when the schedule function was called, it would disable tracing. But the count should only be decremented once (to 2). Then if the user enabled tracing again (via tracing_on file), the next call to schedule would disable tracing again and the count would be decremented to 1. But if multiple CPUS called schedule at the same time, it is possible that the count would be decremented more than once because of the simple "count--" used. By reading the count into a local variable and using memory barriers we can guarantee that the count would only be decremented once per disable (or enable). The stack trace probe had a similar race, but here the stack trace will decrement for each time it is called. But this had the read-modify- write race, where it could stack trace more than the number of times that was specified. This case we use a cmpxchg to stack trace only the number of times specified. The dump probes can still use the old "update_count()" function as they only run once, and that is controlled by the dump logic itself. Link: http://lkml.kernel.org/r/20141118134643.4b550ee4@gandalf.local.home Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-11-18 04:08:24 +00:00
* It is fine if both disable (or enable) tracing, as disabling
* (or enabling) the second time doesn't do anything as the
* state of the tracer is already disabled (or enabled).
* What needs to be synchronized in this case is that the count
* only gets decremented once, even if the tracer is disabled
* (or enabled) twice, as the second one is really a nop.
*
* The memory barriers guarantee that we only decrement the
* counter once. First the count is read to a local variable
* and a read barrier is used to make sure that it is loaded
* before checking if the tracer is in the state we want.
* If the tracer is not in the state we want, then the count
* is guaranteed to be the old count.
*
* Next the tracer is set to the state we want (disabled or enabled)
* then a write memory barrier is used to make sure that
* the new state is visible before changing the counter by
* one minus the old counter. This guarantees that another CPU
* executing this code will see the new state before seeing
* the new counter value, and would not do anything if the new
tracing: Fix race of function probes counting The function probe counting for traceon and traceoff suffered a race condition where if the probe was executing on two or more CPUs at the same time, it could decrement the counter by more than one when disabling (or enabling) the tracer only once. The way the traceon and traceoff probes are suppose to work is that they disable (or enable) tracing once per count. If a user were to echo 'schedule:traceoff:3' into set_ftrace_filter, then when the schedule function was called, it would disable tracing. But the count should only be decremented once (to 2). Then if the user enabled tracing again (via tracing_on file), the next call to schedule would disable tracing again and the count would be decremented to 1. But if multiple CPUS called schedule at the same time, it is possible that the count would be decremented more than once because of the simple "count--" used. By reading the count into a local variable and using memory barriers we can guarantee that the count would only be decremented once per disable (or enable). The stack trace probe had a similar race, but here the stack trace will decrement for each time it is called. But this had the read-modify- write race, where it could stack trace more than the number of times that was specified. This case we use a cmpxchg to stack trace only the number of times specified. The dump probes can still use the old "update_count()" function as they only run once, and that is controlled by the dump logic itself. Link: http://lkml.kernel.org/r/20141118134643.4b550ee4@gandalf.local.home Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-11-18 04:08:24 +00:00
* counter is seen.
*
* Note, there is no synchronization between this and a user
* setting the tracing_on file. But we currently don't care
* about that.
*/
if (!old_count)
return;
tracing: Fix race of function probes counting The function probe counting for traceon and traceoff suffered a race condition where if the probe was executing on two or more CPUs at the same time, it could decrement the counter by more than one when disabling (or enabling) the tracer only once. The way the traceon and traceoff probes are suppose to work is that they disable (or enable) tracing once per count. If a user were to echo 'schedule:traceoff:3' into set_ftrace_filter, then when the schedule function was called, it would disable tracing. But the count should only be decremented once (to 2). Then if the user enabled tracing again (via tracing_on file), the next call to schedule would disable tracing again and the count would be decremented to 1. But if multiple CPUS called schedule at the same time, it is possible that the count would be decremented more than once because of the simple "count--" used. By reading the count into a local variable and using memory barriers we can guarantee that the count would only be decremented once per disable (or enable). The stack trace probe had a similar race, but here the stack trace will decrement for each time it is called. But this had the read-modify- write race, where it could stack trace more than the number of times that was specified. This case we use a cmpxchg to stack trace only the number of times specified. The dump probes can still use the old "update_count()" function as they only run once, and that is controlled by the dump logic itself. Link: http://lkml.kernel.org/r/20141118134643.4b550ee4@gandalf.local.home Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-11-18 04:08:24 +00:00
/* Make sure we see count before checking tracing state */
smp_rmb();
tracing: Fix race of function probes counting The function probe counting for traceon and traceoff suffered a race condition where if the probe was executing on two or more CPUs at the same time, it could decrement the counter by more than one when disabling (or enabling) the tracer only once. The way the traceon and traceoff probes are suppose to work is that they disable (or enable) tracing once per count. If a user were to echo 'schedule:traceoff:3' into set_ftrace_filter, then when the schedule function was called, it would disable tracing. But the count should only be decremented once (to 2). Then if the user enabled tracing again (via tracing_on file), the next call to schedule would disable tracing again and the count would be decremented to 1. But if multiple CPUS called schedule at the same time, it is possible that the count would be decremented more than once because of the simple "count--" used. By reading the count into a local variable and using memory barriers we can guarantee that the count would only be decremented once per disable (or enable). The stack trace probe had a similar race, but here the stack trace will decrement for each time it is called. But this had the read-modify- write race, where it could stack trace more than the number of times that was specified. This case we use a cmpxchg to stack trace only the number of times specified. The dump probes can still use the old "update_count()" function as they only run once, and that is controlled by the dump logic itself. Link: http://lkml.kernel.org/r/20141118134643.4b550ee4@gandalf.local.home Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-11-18 04:08:24 +00:00
if (on == !!tracing_is_on())
return;
if (on)
tracing_on();
else
tracing_off();
/* unlimited? */
if (old_count == -1)
return;
/* Make sure tracing state is visible before updating count */
smp_wmb();
*count = old_count - 1;
}
static void
ftrace_traceon_count(unsigned long ip, unsigned long parent_ip, void **data)
{
tracing: Fix race of function probes counting The function probe counting for traceon and traceoff suffered a race condition where if the probe was executing on two or more CPUs at the same time, it could decrement the counter by more than one when disabling (or enabling) the tracer only once. The way the traceon and traceoff probes are suppose to work is that they disable (or enable) tracing once per count. If a user were to echo 'schedule:traceoff:3' into set_ftrace_filter, then when the schedule function was called, it would disable tracing. But the count should only be decremented once (to 2). Then if the user enabled tracing again (via tracing_on file), the next call to schedule would disable tracing again and the count would be decremented to 1. But if multiple CPUS called schedule at the same time, it is possible that the count would be decremented more than once because of the simple "count--" used. By reading the count into a local variable and using memory barriers we can guarantee that the count would only be decremented once per disable (or enable). The stack trace probe had a similar race, but here the stack trace will decrement for each time it is called. But this had the read-modify- write race, where it could stack trace more than the number of times that was specified. This case we use a cmpxchg to stack trace only the number of times specified. The dump probes can still use the old "update_count()" function as they only run once, and that is controlled by the dump logic itself. Link: http://lkml.kernel.org/r/20141118134643.4b550ee4@gandalf.local.home Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-11-18 04:08:24 +00:00
update_traceon_count(data, 1);
}
static void
ftrace_traceoff_count(unsigned long ip, unsigned long parent_ip, void **data)
{
tracing: Fix race of function probes counting The function probe counting for traceon and traceoff suffered a race condition where if the probe was executing on two or more CPUs at the same time, it could decrement the counter by more than one when disabling (or enabling) the tracer only once. The way the traceon and traceoff probes are suppose to work is that they disable (or enable) tracing once per count. If a user were to echo 'schedule:traceoff:3' into set_ftrace_filter, then when the schedule function was called, it would disable tracing. But the count should only be decremented once (to 2). Then if the user enabled tracing again (via tracing_on file), the next call to schedule would disable tracing again and the count would be decremented to 1. But if multiple CPUS called schedule at the same time, it is possible that the count would be decremented more than once because of the simple "count--" used. By reading the count into a local variable and using memory barriers we can guarantee that the count would only be decremented once per disable (or enable). The stack trace probe had a similar race, but here the stack trace will decrement for each time it is called. But this had the read-modify- write race, where it could stack trace more than the number of times that was specified. This case we use a cmpxchg to stack trace only the number of times specified. The dump probes can still use the old "update_count()" function as they only run once, and that is controlled by the dump logic itself. Link: http://lkml.kernel.org/r/20141118134643.4b550ee4@gandalf.local.home Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-11-18 04:08:24 +00:00
update_traceon_count(data, 0);
}
static void
ftrace_traceon(unsigned long ip, unsigned long parent_ip, void **data)
{
if (tracing_is_on())
return;
tracing_on();
}
static void
ftrace_traceoff(unsigned long ip, unsigned long parent_ip, void **data)
{
if (!tracing_is_on())
return;
tracing_off();
}
/*
* Skip 4:
* ftrace_stacktrace()
* function_trace_probe_call()
* ftrace_ops_list_func()
* ftrace_call()
*/
#define STACK_SKIP 4
static void
ftrace_stacktrace(unsigned long ip, unsigned long parent_ip, void **data)
{
trace_dump_stack(STACK_SKIP);
}
static void
ftrace_stacktrace_count(unsigned long ip, unsigned long parent_ip, void **data)
{
tracing: Fix race of function probes counting The function probe counting for traceon and traceoff suffered a race condition where if the probe was executing on two or more CPUs at the same time, it could decrement the counter by more than one when disabling (or enabling) the tracer only once. The way the traceon and traceoff probes are suppose to work is that they disable (or enable) tracing once per count. If a user were to echo 'schedule:traceoff:3' into set_ftrace_filter, then when the schedule function was called, it would disable tracing. But the count should only be decremented once (to 2). Then if the user enabled tracing again (via tracing_on file), the next call to schedule would disable tracing again and the count would be decremented to 1. But if multiple CPUS called schedule at the same time, it is possible that the count would be decremented more than once because of the simple "count--" used. By reading the count into a local variable and using memory barriers we can guarantee that the count would only be decremented once per disable (or enable). The stack trace probe had a similar race, but here the stack trace will decrement for each time it is called. But this had the read-modify- write race, where it could stack trace more than the number of times that was specified. This case we use a cmpxchg to stack trace only the number of times specified. The dump probes can still use the old "update_count()" function as they only run once, and that is controlled by the dump logic itself. Link: http://lkml.kernel.org/r/20141118134643.4b550ee4@gandalf.local.home Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-11-18 04:08:24 +00:00
long *count = (long *)data;
long old_count;
long new_count;
/*
* Stack traces should only execute the number of times the
* user specified in the counter.
*/
do {
if (!tracing_is_on())
return;
tracing: Fix race of function probes counting The function probe counting for traceon and traceoff suffered a race condition where if the probe was executing on two or more CPUs at the same time, it could decrement the counter by more than one when disabling (or enabling) the tracer only once. The way the traceon and traceoff probes are suppose to work is that they disable (or enable) tracing once per count. If a user were to echo 'schedule:traceoff:3' into set_ftrace_filter, then when the schedule function was called, it would disable tracing. But the count should only be decremented once (to 2). Then if the user enabled tracing again (via tracing_on file), the next call to schedule would disable tracing again and the count would be decremented to 1. But if multiple CPUS called schedule at the same time, it is possible that the count would be decremented more than once because of the simple "count--" used. By reading the count into a local variable and using memory barriers we can guarantee that the count would only be decremented once per disable (or enable). The stack trace probe had a similar race, but here the stack trace will decrement for each time it is called. But this had the read-modify- write race, where it could stack trace more than the number of times that was specified. This case we use a cmpxchg to stack trace only the number of times specified. The dump probes can still use the old "update_count()" function as they only run once, and that is controlled by the dump logic itself. Link: http://lkml.kernel.org/r/20141118134643.4b550ee4@gandalf.local.home Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-11-18 04:08:24 +00:00
old_count = *count;
if (!old_count)
return;
/* unlimited? */
if (old_count == -1) {
trace_dump_stack(STACK_SKIP);
return;
}
new_count = old_count - 1;
new_count = cmpxchg(count, old_count, new_count);
if (new_count == old_count)
trace_dump_stack(STACK_SKIP);
} while (new_count != old_count);
}
static int update_count(void **data)
{
unsigned long *count = (long *)data;
if (!*count)
return 0;
if (*count != -1)
(*count)--;
return 1;
}
static void
ftrace_dump_probe(unsigned long ip, unsigned long parent_ip, void **data)
{
if (update_count(data))
ftrace_dump(DUMP_ALL);
}
/* Only dump the current CPU buffer. */
static void
ftrace_cpudump_probe(unsigned long ip, unsigned long parent_ip, void **data)
{
if (update_count(data))
ftrace_dump(DUMP_ORIG);
}
static int
ftrace_probe_print(const char *name, struct seq_file *m,
unsigned long ip, void *data)
{
long count = (long)data;
seq_printf(m, "%ps:%s", (void *)ip, name);
if (count == -1)
seq_puts(m, ":unlimited\n");
else
seq_printf(m, ":count=%ld\n", count);
return 0;
}
static int
ftrace_traceon_print(struct seq_file *m, unsigned long ip,
struct ftrace_probe_ops *ops, void *data)
{
return ftrace_probe_print("traceon", m, ip, data);
}
static int
ftrace_traceoff_print(struct seq_file *m, unsigned long ip,
struct ftrace_probe_ops *ops, void *data)
{
return ftrace_probe_print("traceoff", m, ip, data);
}
static int
ftrace_stacktrace_print(struct seq_file *m, unsigned long ip,
struct ftrace_probe_ops *ops, void *data)
{
return ftrace_probe_print("stacktrace", m, ip, data);
}
static int
ftrace_dump_print(struct seq_file *m, unsigned long ip,
struct ftrace_probe_ops *ops, void *data)
{
return ftrace_probe_print("dump", m, ip, data);
}
static int
ftrace_cpudump_print(struct seq_file *m, unsigned long ip,
struct ftrace_probe_ops *ops, void *data)
{
return ftrace_probe_print("cpudump", m, ip, data);
}
static struct ftrace_probe_ops traceon_count_probe_ops = {
.func = ftrace_traceon_count,
.print = ftrace_traceon_print,
};
static struct ftrace_probe_ops traceoff_count_probe_ops = {
.func = ftrace_traceoff_count,
.print = ftrace_traceoff_print,
};
static struct ftrace_probe_ops stacktrace_count_probe_ops = {
.func = ftrace_stacktrace_count,
.print = ftrace_stacktrace_print,
};
static struct ftrace_probe_ops dump_probe_ops = {
.func = ftrace_dump_probe,
.print = ftrace_dump_print,
};
static struct ftrace_probe_ops cpudump_probe_ops = {
.func = ftrace_cpudump_probe,
.print = ftrace_cpudump_print,
};
static struct ftrace_probe_ops traceon_probe_ops = {
.func = ftrace_traceon,
.print = ftrace_traceon_print,
};
static struct ftrace_probe_ops traceoff_probe_ops = {
.func = ftrace_traceoff,
.print = ftrace_traceoff_print,
};
static struct ftrace_probe_ops stacktrace_probe_ops = {
.func = ftrace_stacktrace,
.print = ftrace_stacktrace_print,
};
static int
ftrace_trace_probe_callback(struct ftrace_probe_ops *ops,
struct ftrace_hash *hash, char *glob,
char *cmd, char *param, int enable)
{
void *count = (void *)-1;
char *number;
int ret;
/* hash funcs only work with set_ftrace_filter */
if (!enable)
return -EINVAL;
if (glob[0] == '!') {
unregister_ftrace_function_probe_func(glob+1, ops);
return 0;
}
if (!param)
goto out_reg;
number = strsep(&param, ":");
if (!strlen(number))
goto out_reg;
/*
* We use the callback data field (which is a pointer)
* as our counter.
*/
ret = kstrtoul(number, 0, (unsigned long *)&count);
if (ret)
return ret;
out_reg:
ret = register_ftrace_function_probe(glob, ops, count);
tracing/function: Fix the return value of ftrace_trace_onoff_callback() ftrace_trace_onoff_callback() will return an error even if we do the right operation, for example: # echo _spin_*:traceon:10 > set_ftrace_filter -bash: echo: write error: Invalid argument # cat set_ftrace_filter #### all functions enabled #### _spin_trylock_bh:traceon:count=10 _spin_unlock_irq:traceon:count=10 _spin_unlock_bh:traceon:count=10 _spin_lock_irq:traceon:count=10 _spin_unlock:traceon:count=10 _spin_trylock:traceon:count=10 _spin_unlock_irqrestore:traceon:count=10 _spin_lock_irqsave:traceon:count=10 _spin_lock_bh:traceon:count=10 _spin_lock:traceon:count=10 We want to set _spin_*:traceon:10 to set_ftrace_filter, it complains with "Invalid argument", but the operation is successful. This is because ftrace_process_regex() returns the number of functions that matched the pattern. If the number is not 0, this value is returned by ftrace_regex_write() whereas we want to return the number of bytes virtually written. Also the file offset pointer is not updated in this case. If the number of matched functions is lower than the number of bytes written by the user, this results to a reprocessing of the string given by the user with a lower size, leading to a malformed ftrace regex and then a -EINVAL returned. So, this patch fixes it by returning 0 if no error occured. The fix also applies on 2.6.30 Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Cc: stable@kernel.org Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-07-15 04:29:06 +00:00
return ret < 0 ? ret : 0;
}
static int
ftrace_trace_onoff_callback(struct ftrace_hash *hash,
char *glob, char *cmd, char *param, int enable)
{
struct ftrace_probe_ops *ops;
/* we register both traceon and traceoff to this callback */
if (strcmp(cmd, "traceon") == 0)
ops = param ? &traceon_count_probe_ops : &traceon_probe_ops;
else
ops = param ? &traceoff_count_probe_ops : &traceoff_probe_ops;
return ftrace_trace_probe_callback(ops, hash, glob, cmd,
param, enable);
}
static int
ftrace_stacktrace_callback(struct ftrace_hash *hash,
char *glob, char *cmd, char *param, int enable)
{
struct ftrace_probe_ops *ops;
ops = param ? &stacktrace_count_probe_ops : &stacktrace_probe_ops;
return ftrace_trace_probe_callback(ops, hash, glob, cmd,
param, enable);
}
static int
ftrace_dump_callback(struct ftrace_hash *hash,
char *glob, char *cmd, char *param, int enable)
{
struct ftrace_probe_ops *ops;
ops = &dump_probe_ops;
/* Only dump once. */
return ftrace_trace_probe_callback(ops, hash, glob, cmd,
"1", enable);
}
static int
ftrace_cpudump_callback(struct ftrace_hash *hash,
char *glob, char *cmd, char *param, int enable)
{
struct ftrace_probe_ops *ops;
ops = &cpudump_probe_ops;
/* Only dump once. */
return ftrace_trace_probe_callback(ops, hash, glob, cmd,
"1", enable);
}
static struct ftrace_func_command ftrace_traceon_cmd = {
.name = "traceon",
.func = ftrace_trace_onoff_callback,
};
static struct ftrace_func_command ftrace_traceoff_cmd = {
.name = "traceoff",
.func = ftrace_trace_onoff_callback,
};
static struct ftrace_func_command ftrace_stacktrace_cmd = {
.name = "stacktrace",
.func = ftrace_stacktrace_callback,
};
static struct ftrace_func_command ftrace_dump_cmd = {
.name = "dump",
.func = ftrace_dump_callback,
};
static struct ftrace_func_command ftrace_cpudump_cmd = {
.name = "cpudump",
.func = ftrace_cpudump_callback,
};
static int __init init_func_cmd_traceon(void)
{
int ret;
ret = register_ftrace_command(&ftrace_traceoff_cmd);
if (ret)
return ret;
ret = register_ftrace_command(&ftrace_traceon_cmd);
if (ret)
goto out_free_traceoff;
ret = register_ftrace_command(&ftrace_stacktrace_cmd);
if (ret)
goto out_free_traceon;
ret = register_ftrace_command(&ftrace_dump_cmd);
if (ret)
goto out_free_stacktrace;
ret = register_ftrace_command(&ftrace_cpudump_cmd);
if (ret)
goto out_free_dump;
return 0;
out_free_dump:
unregister_ftrace_command(&ftrace_dump_cmd);
out_free_stacktrace:
unregister_ftrace_command(&ftrace_stacktrace_cmd);
out_free_traceon:
unregister_ftrace_command(&ftrace_traceon_cmd);
out_free_traceoff:
unregister_ftrace_command(&ftrace_traceoff_cmd);
return ret;
}
#else
static inline int init_func_cmd_traceon(void)
{
return 0;
}
#endif /* CONFIG_DYNAMIC_FTRACE */
ftrace: function tracer This is a simple trace that uses the ftrace infrastructure. It is designed to be fast and small, and easy to use. It is useful to record things that happen over a very short period of time, and not to analyze the system in general. Updates: available_tracers "function" is added to this file. current_tracer To enable the function tracer: echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer The output of the function_trace file is as follows "echo noverbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst Signed-off-by: Ingo Molnar <mingo@elte.hu> -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / swapper-0 0d.h. 1595128us+: set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper-0 0d.h. 1595131us+: _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) Or with verbose turned on: "echo verbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- swapper 0 0 9 00000000 00000000 [f3675f41] 1595.128ms (+0.003ms): set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper 0 0 9 00000000 00000001 [f3675f45] 1595.131ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) swapper 0 0 9 00000000 00000002 [f3675f48] 1595.135ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) The "trace" file is not affected by the verbose mode, but is by the symonly. echo "nosymonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479967] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <ffffffff80337a4d> <-- _spin_unlock_irqrestore+0xe/0x5a <ffffffff8048cc8f> [ 81.479967] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <ffffffff8048ccbf> <-- sub_preempt_count+0xc/0x7a <ffffffff80233d7b> [ 81.479968] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <ffffffff80233d9f> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> [ 81.479968] CPU 0: bash:3154 vfs_write+0x11d/0x155 <ffffffff8029a043> <-- dnotify_parent+0x12/0x78 <ffffffff802d54fb> [ 81.479968] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <ffffffff802d5516> <-- _spin_lock+0xe/0x70 <ffffffff8048c910> [ 81.479969] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <ffffffff8048c91d> <-- add_preempt_count+0xe/0x77 <ffffffff80233df7> [ 81.479969] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <ffffffff80233e27> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> echo "symonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479913] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <-- _spin_unlock_irqrestore+0xe/0x5a [ 81.479913] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <-- sub_preempt_count+0xc/0x7a [ 81.479913] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <-- in_lock_functions+0x9/0x24 [ 81.479914] CPU 0: bash:3154 vfs_write+0x11d/0x155 <-- dnotify_parent+0x12/0x78 [ 81.479914] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <-- _spin_lock+0xe/0x70 [ 81.479914] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <-- add_preempt_count+0xe/0x77 [ 81.479914] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <-- in_lock_functions+0x9/0x24 Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 19:20:42 +00:00
static __init int init_function_trace(void)
{
init_func_cmd_traceon();
ftrace: function tracer This is a simple trace that uses the ftrace infrastructure. It is designed to be fast and small, and easy to use. It is useful to record things that happen over a very short period of time, and not to analyze the system in general. Updates: available_tracers "function" is added to this file. current_tracer To enable the function tracer: echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer The output of the function_trace file is as follows "echo noverbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst Signed-off-by: Ingo Molnar <mingo@elte.hu> -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / swapper-0 0d.h. 1595128us+: set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper-0 0d.h. 1595131us+: _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) Or with verbose turned on: "echo verbose > /debugfs/tracing/iter_ctrl" preemption latency trace v1.1.5 on 2.6.24-rc7-tst -------------------------------------------------------------------- latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- swapper 0 0 9 00000000 00000000 [f3675f41] 1595.128ms (+0.003ms): set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>) swapper 0 0 9 00000000 00000001 [f3675f45] 1595.131ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) swapper 0 0 9 00000000 00000002 [f3675f48] 1595.135ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>) The "trace" file is not affected by the verbose mode, but is by the symonly. echo "nosymonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479967] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <ffffffff80337a4d> <-- _spin_unlock_irqrestore+0xe/0x5a <ffffffff8048cc8f> [ 81.479967] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <ffffffff8048ccbf> <-- sub_preempt_count+0xc/0x7a <ffffffff80233d7b> [ 81.479968] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <ffffffff80233d9f> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> [ 81.479968] CPU 0: bash:3154 vfs_write+0x11d/0x155 <ffffffff8029a043> <-- dnotify_parent+0x12/0x78 <ffffffff802d54fb> [ 81.479968] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <ffffffff802d5516> <-- _spin_lock+0xe/0x70 <ffffffff8048c910> [ 81.479969] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <ffffffff8048c91d> <-- add_preempt_count+0xe/0x77 <ffffffff80233df7> [ 81.479969] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <ffffffff80233e27> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d> echo "symonly" > /debugfs/tracing/iter_ctrl tracer: [ 81.479913] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <-- _spin_unlock_irqrestore+0xe/0x5a [ 81.479913] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <-- sub_preempt_count+0xc/0x7a [ 81.479913] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <-- in_lock_functions+0x9/0x24 [ 81.479914] CPU 0: bash:3154 vfs_write+0x11d/0x155 <-- dnotify_parent+0x12/0x78 [ 81.479914] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <-- _spin_lock+0xe/0x70 [ 81.479914] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <-- add_preempt_count+0xe/0x77 [ 81.479914] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <-- in_lock_functions+0x9/0x24 Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 19:20:42 +00:00
return register_tracer(&function_trace);
}
core_initcall(init_function_trace);