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If we want to stop the tick further idle, we need to be able to account the cputime without using the tick. Virtual based cputime accounting solves that problem by hooking into kernel/user boundaries. However implementing CONFIG_VIRT_CPU_ACCOUNTING require low level hooks and involves more overhead. But we already have a generic context tracking subsystem that is required for RCU needs by archs which plan to shut down the tick outside idle. This patch implements a generic virtual based cputime accounting that relies on these generic kernel/user hooks. There are some upsides of doing this: - This requires no arch code to implement CONFIG_VIRT_CPU_ACCOUNTING if context tracking is already built (already necessary for RCU in full tickless mode). - We can rely on the generic context tracking subsystem to dynamically (de)activate the hooks, so that we can switch anytime between virtual and tick based accounting. This way we don't have the overhead of the virtual accounting when the tick is running periodically. And one downside: - There is probably more overhead than a native virtual based cputime accounting. But this relies on hooks that are already set anyway. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de>
158 lines
4.7 KiB
C
158 lines
4.7 KiB
C
/*
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* lppaca.h
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* Copyright (C) 2001 Mike Corrigan IBM Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef _ASM_POWERPC_LPPACA_H
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#define _ASM_POWERPC_LPPACA_H
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#ifdef __KERNEL__
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/*
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* These definitions relate to hypervisors that only exist when using
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* a server type processor
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*/
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#ifdef CONFIG_PPC_BOOK3S
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/*
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* This control block contains the data that is shared between the
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* hypervisor and the OS.
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*/
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#include <linux/cache.h>
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#include <linux/threads.h>
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#include <asm/types.h>
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#include <asm/mmu.h>
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/*
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* We only have to have statically allocated lppaca structs on
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* legacy iSeries, which supports at most 64 cpus.
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*/
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#define NR_LPPACAS 1
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/*
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* The Hypervisor barfs if the lppaca crosses a page boundary. A 1k
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* alignment is sufficient to prevent this
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*/
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struct lppaca {
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/* cacheline 1 contains read-only data */
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u32 desc; /* Eye catcher 0xD397D781 */
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u16 size; /* Size of this struct */
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u16 reserved1;
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u16 reserved2:14;
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u8 shared_proc:1; /* Shared processor indicator */
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u8 secondary_thread:1; /* Secondary thread indicator */
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u8 reserved3[14];
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volatile u32 dyn_hw_node_id; /* Dynamic hardware node id */
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volatile u32 dyn_hw_proc_id; /* Dynamic hardware proc id */
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u8 reserved4[56];
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volatile u8 vphn_assoc_counts[8]; /* Virtual processor home node */
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/* associativity change counters */
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u8 reserved5[32];
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/* cacheline 2 contains local read-write data */
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u8 reserved6[48];
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u8 cede_latency_hint;
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u8 reserved7[7];
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u8 dtl_enable_mask; /* Dispatch Trace Log mask */
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u8 donate_dedicated_cpu; /* Donate dedicated CPU cycles */
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u8 fpregs_in_use;
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u8 pmcregs_in_use;
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u8 reserved8[28];
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u64 wait_state_cycles; /* Wait cycles for this proc */
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u8 reserved9[28];
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u16 slb_count; /* # of SLBs to maintain */
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u8 idle; /* Indicate OS is idle */
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u8 vmxregs_in_use;
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/* cacheline 3 is shared with other processors */
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/*
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* This is the yield_count. An "odd" value (low bit on) means that
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* the processor is yielded (either because of an OS yield or a
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* hypervisor preempt). An even value implies that the processor is
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* currently executing.
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* NOTE: This value will ALWAYS be zero for dedicated processors and
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* will NEVER be zero for shared processors (ie, initialized to a 1).
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*/
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volatile u32 yield_count;
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volatile u32 dispersion_count; /* dispatch changed physical cpu */
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volatile u64 cmo_faults; /* CMO page fault count */
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volatile u64 cmo_fault_time; /* CMO page fault time */
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u8 reserved10[104];
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/* cacheline 4-5 */
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u32 page_ins; /* CMO Hint - # page ins by OS */
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u8 reserved11[148];
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volatile u64 dtl_idx; /* Dispatch Trace Log head index */
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u8 reserved12[96];
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} __attribute__((__aligned__(0x400)));
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extern struct lppaca lppaca[];
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#define lppaca_of(cpu) (*paca[cpu].lppaca_ptr)
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/*
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* SLB shadow buffer structure as defined in the PAPR. The save_area
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* contains adjacent ESID and VSID pairs for each shadowed SLB. The
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* ESID is stored in the lower 64bits, then the VSID.
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*/
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struct slb_shadow {
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u32 persistent; /* Number of persistent SLBs */
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u32 buffer_length; /* Total shadow buffer length */
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u64 reserved;
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struct {
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u64 esid;
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u64 vsid;
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} save_area[SLB_NUM_BOLTED];
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} ____cacheline_aligned;
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extern struct slb_shadow slb_shadow[];
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/*
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* Layout of entries in the hypervisor's dispatch trace log buffer.
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*/
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struct dtl_entry {
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u8 dispatch_reason;
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u8 preempt_reason;
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u16 processor_id;
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u32 enqueue_to_dispatch_time;
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u32 ready_to_enqueue_time;
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u32 waiting_to_ready_time;
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u64 timebase;
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u64 fault_addr;
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u64 srr0;
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u64 srr1;
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};
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#define DISPATCH_LOG_BYTES 4096 /* bytes per cpu */
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#define N_DISPATCH_LOG (DISPATCH_LOG_BYTES / sizeof(struct dtl_entry))
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extern struct kmem_cache *dtl_cache;
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/*
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* When CONFIG_VIRT_CPU_ACCOUNTING_NATIVE = y, the cpu accounting code controls
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* reading from the dispatch trace log. If other code wants to consume
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* DTL entries, it can set this pointer to a function that will get
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* called once for each DTL entry that gets processed.
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*/
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extern void (*dtl_consumer)(struct dtl_entry *entry, u64 index);
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#endif /* CONFIG_PPC_BOOK3S */
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#endif /* __KERNEL__ */
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#endif /* _ASM_POWERPC_LPPACA_H */
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