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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-12-16 17:55:54 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-12-16 18:30:11 +0100 |
| commit | f4c4176f21533e22bcc292030da72bcfa105f5b8 (patch) | |
| tree | 9e4376f5ff4dc3fb0f333faca94f219570df9af8 /kernel/perf_event.c | |
| parent | 9b33827de63539c7c3314ddf890fb216e4acf3d8 (diff) | |
| download | lwn-f4c4176f21533e22bcc292030da72bcfa105f5b8.tar.gz lwn-f4c4176f21533e22bcc292030da72bcfa105f5b8.zip | |
perf events: Allow per-task-per-cpu counters
In order to allow for per-task-per-cpu counters, useful for
scalability when profiling task hierarchies, we allow installing
events with event->cpu != -1 in task contexts.
__perf_event_sched_in() already skips events where ->cpu
mis-matches the current cpu, fix up __perf_install_in_context()
and __perf_event_enable() to also respect this filter.
This does lead to vary hard to interpret enabled/running times
for such counters, but I don't see a simple solution for that.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: fweisbec@gmail.com
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091216165904.831451147@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/perf_event.c')
| -rw-r--r-- | kernel/perf_event.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 0dd8e5d02c66..2e0aaa34fc7e 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -782,6 +782,9 @@ static void __perf_install_in_context(void *info) add_event_to_ctx(event, ctx); + if (event->cpu != -1 && event->cpu != smp_processor_id()) + goto unlock; + /* * Don't put the event on if it is disabled or if * it is in a group and the group isn't on. @@ -925,6 +928,9 @@ static void __perf_event_enable(void *info) goto unlock; __perf_event_mark_enabled(event, ctx); + if (event->cpu != -1 && event->cpu != smp_processor_id()) + goto unlock; + /* * If the event is in a group and isn't the group leader, * then don't put it on unless the group is on. @@ -1595,10 +1601,7 @@ static struct perf_event_context *find_get_context(pid_t pid, int cpu) unsigned long flags; int err; - /* - * If cpu is not a wildcard then this is a percpu event: - */ - if (cpu != -1) { + if (pid == -1 && cpu != -1) { /* Must be root to operate on a CPU event: */ if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN)) return ERR_PTR(-EACCES); |