perf tools: Add support for breakpoint events in perf tools

Add the breakpoint events support with this new sysnopsis:

  mem:addr[:access]

Where addr is a raw addr value in the kernel and access can be
either [r][w][x]

Example to profile tasklist_lock:

	$ grep tasklist_lock /proc/kallsyms
	ffffffff8189c000 D tasklist_lock

	$ perf record -e mem:0xffffffff8189c000:rw -a -f -c 1
	$ perf report

	# Samples: 62
	#
	# Overhead          Command  Shared Object  Symbol
	# ........  ...............  .............  ......
	#
	    29.03%          swapper  [kernel]       [k] _raw_read_trylock
	    29.03%          swapper  [kernel]       [k] _raw_read_unlock
	    19.35%             init  [kernel]       [k] _raw_read_trylock
	    19.35%             init  [kernel]       [k] _raw_read_unlock
	     1.61%         events/0  [kernel]       [k] _raw_read_trylock
	     1.61%         events/0  [kernel]       [k] _raw_read_unlock

Coming soon:

 - Support for symbols in the event definition.

 - Default period to 1 for breakpoint events because these are
   not high frequency events. The same thing is needed for trace
   events.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Prasad <prasad@linux.vnet.ibm.com>
LKML-Reference: <1258987355-8751-4-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Prasad <prasad@linux.vnet.ibm.com>
This commit is contained in:
Frederic Weisbecker 2009-11-23 15:42:35 +01:00 committed by Ingo Molnar
parent f5ffe02e50
commit 1b290d670f
2 changed files with 95 additions and 5 deletions

View File

@ -26,11 +26,19 @@ OPTIONS
-e::
--event=::
Select the PMU event. Selection can be a symbolic event name
(use 'perf list' to list all events) or a raw PMU
event (eventsel+umask) in the form of rNNN where NNN is a
hexadecimal event descriptor.
Select the PMU event. Selection can be:
- a symbolic event name (use 'perf list' to list all events)
- a raw PMU event (eventsel+umask) in the form of rNNN where NNN is a
hexadecimal event descriptor.
- a hardware breakpoint event in the form of '\mem:addr[:access]'
where addr is the address in memory you want to break in.
Access is the memory access type (read, write, execute) it can
be passed as follows: '\mem:addr[:[r][w][x]]'.
If you want to profile read-write accesses in 0x1000, just set
'mem:0x1000:rw'.
-a::
System-wide collection.

View File

@ -1,4 +1,4 @@
#include "../../../include/linux/hw_breakpoint.h"
#include "util.h"
#include "../perf.h"
#include "parse-options.h"
@ -540,6 +540,81 @@ static enum event_result parse_tracepoint_event(const char **strp,
attr, strp);
}
static enum event_result
parse_breakpoint_type(const char *type, const char **strp,
struct perf_event_attr *attr)
{
int i;
for (i = 0; i < 3; i++) {
if (!type[i])
break;
switch (type[i]) {
case 'r':
attr->bp_type |= HW_BREAKPOINT_R;
break;
case 'w':
attr->bp_type |= HW_BREAKPOINT_W;
break;
case 'x':
attr->bp_type |= HW_BREAKPOINT_X;
break;
default:
return EVT_FAILED;
}
}
if (!attr->bp_type) /* Default */
attr->bp_type = HW_BREAKPOINT_R | HW_BREAKPOINT_W;
*strp = type + i;
return EVT_HANDLED;
}
static enum event_result
parse_breakpoint_event(const char **strp, struct perf_event_attr *attr)
{
const char *target;
const char *type;
char *endaddr;
u64 addr;
enum event_result err;
target = strchr(*strp, ':');
if (!target)
return EVT_FAILED;
if (strncmp(*strp, "mem", target - *strp) != 0)
return EVT_FAILED;
target++;
addr = strtoull(target, &endaddr, 0);
if (target == endaddr)
return EVT_FAILED;
attr->bp_addr = addr;
*strp = endaddr;
type = strchr(target, ':');
/* If no type is defined, just rw as default */
if (!type) {
attr->bp_type = HW_BREAKPOINT_R | HW_BREAKPOINT_W;
} else {
err = parse_breakpoint_type(++type, strp, attr);
if (err == EVT_FAILED)
return EVT_FAILED;
}
/* We should find a nice way to override the access type */
attr->bp_len = HW_BREAKPOINT_LEN_4;
attr->type = PERF_TYPE_BREAKPOINT;
return EVT_HANDLED;
}
static int check_events(const char *str, unsigned int i)
{
int n;
@ -673,6 +748,10 @@ parse_event_symbols(const char **str, struct perf_event_attr *attr)
if (ret != EVT_FAILED)
goto modifier;
ret = parse_breakpoint_event(str, attr);
if (ret != EVT_FAILED)
goto modifier;
fprintf(stderr, "invalid or unsupported event: '%s'\n", *str);
fprintf(stderr, "Run 'perf list' for a list of valid events\n");
return EVT_FAILED;
@ -859,6 +938,9 @@ void print_events(void)
"rNNN");
printf("\n");
printf(" %-42s [hardware breakpoint]\n", "mem:<addr>[:access]");
printf("\n");
print_tracepoint_events();
exit(129);