diff options
| author |   Peter Zijlstra <peterz@infradead.org> | 2009-11-23 15:00:36 +0100 |
|---|---|---|
| committer |   Ingo Molnar <mingo@elte.hu> | 2009-11-23 15:22:19 +0100 |
| commit | acd1d7c1f8f3d848a3c5327dc09f8c1efb971678 (patch) | |
| tree | 88ec283110f78cf803c71a3d1d919a422f2f13c5 | |
| parent | perf_events: Undo some recursion damage (diff) | |
| download | linux-dev-acd1d7c1f8f3d848a3c5327dc09f8c1efb971678.tar.xz linux-dev-acd1d7c1f8f3d848a3c5327dc09f8c1efb971678.zip | |
perf_events: Restore sanity to scaling land
It is quite possible to call update_event_times() on a context
that isn't actually running and thereby confuse the thing.
perf stat was reporting !100% scale values for software counters
(2e2af50b perf_events: Disable events when we detach them,
solved the worst of that, but there was still some left).
The thing that happens is that because we are not self-reaping
(we have a caring parent) there is a time between the last
schedule (out) and having do_exit() called which will detach the
events.
This period would be accounted as enabled,!running because the
event->state==INACTIVE, even though !event->ctx->is_active.
Similar issues could have been observed by calling read() on a
event while the attached task was not scheduled in.
Solve this by teaching update_event_times() about
ctx->is_active.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1258984836.4531.480.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | kernel/perf_event.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 0b0d5f72fe7d..0aafe85362fd 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -274,7 +274,12 @@ static void update_event_times(struct perf_event *event) event->group_leader->state < PERF_EVENT_STATE_INACTIVE) return; - event->total_time_enabled = ctx->time - event->tstamp_enabled; + if (ctx->is_active) + run_end = ctx->time; + else + run_end = event->tstamp_stopped; + + event->total_time_enabled = run_end - event->tstamp_enabled; if (event->state == PERF_EVENT_STATE_INACTIVE) run_end = event->tstamp_stopped; |