mirrors/linux
2
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-05-09 23:48:56 -04:00
Code Issues Packages Projects Releases Wiki Activity

perf_counter: Provide a way to enable counters on exec

Browse Source 
This provides a way to mark a counter to be enabled on the next
exec. This is useful for measuring the total activity of a
program without including overhead from the process that
launches it.

This also changes the perf stat command to use this new
facility.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <19017.43927.838745.689203@cargo.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Paul Mackerras
2009-06-30 16:07:19 +10:00
committed by Ingo Molnar
parent 051ae7f734
commit 57e7986ed1
3 changed files with 55 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

50
kernel/perf_counter.c
View File

@@ -1428,6 +1428,53 @@ void perf_counter_task_tick(struct task_struct *curr, int cpu)
perf_counter_task_sched_in(curr, cpu);
}
/*
* Enable all of a task's counters that have been marked enable-on-exec.
* This expects task == current.
*/
static void perf_counter_enable_on_exec(struct task_struct *task)
{
struct perf_counter_context *ctx;
struct perf_counter *counter;
unsigned long flags;
int enabled = 0;
local_irq_save(flags);
ctx = task->perf_counter_ctxp;
if (!ctx || !ctx->nr_counters)
goto out;
__perf_counter_task_sched_out(ctx);
spin_lock(&ctx->lock);
list_for_each_entry(counter, &ctx->counter_list, list_entry) {
if (!counter->attr.enable_on_exec)
continue;
counter->attr.enable_on_exec = 0;
if (counter->state >= PERF_COUNTER_STATE_INACTIVE)
continue;
counter->state = PERF_COUNTER_STATE_INACTIVE;
counter->tstamp_enabled =
ctx->time - counter->total_time_enabled;
enabled = 1;
}
/*
* Unclone this context if we enabled any counter.
*/
if (enabled && ctx->parent_ctx) {
put_ctx(ctx->parent_ctx);
ctx->parent_ctx = NULL;
}
spin_unlock(&ctx->lock);
perf_counter_task_sched_in(task, smp_processor_id());
out:
local_irq_restore(flags);
}
/*
* Cross CPU call to read the hardware counter
*/
@@ -2949,6 +2996,9 @@ void perf_counter_comm(struct task_struct *task)
{
struct perf_comm_event comm_event;
if (task->perf_counter_ctxp)
perf_counter_enable_on_exec(task);
if (!atomic_read(&nr_comm_counters))
return;