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authorPeter Zijlstra <peterz@infradead.org>2015-07-27 10:35:07 +0200
committerThomas Gleixner <tglx@linutronix.de>2015-07-27 13:52:19 +0200
commit00a2916f7f82c348a2a94dbb572874173bc308a3 (patch)
treeec5cf352c1cb61b944a9e6c2e969489441370f09 /kernel
parentcbfe8fa6cd672011c755c3cd85c9ffd4e2d10a6f (diff)
perf: Fix running time accounting
A recent fix to the shadow timestamp inadvertly broke the running time accounting. We must not update the running timestamp if we fail to schedule the event, the event will not have ran. This can (and did) result in negative total runtime because the stopped timestamp was before the running timestamp (we 'started' but never stopped the event -- because it never really started we didn't have to stop it either). Reported-and-Tested-by: Vince Weaver <vincent.weaver@maine.edu> Fixes: 72f669c0086f ("perf: Update shadow timestamp before add event") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: stable@vger.kernel.org # 4.1 Cc: Shaohua Li <shli@fb.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/events/core.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index d3dae3419b99..10d076b2572c 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1868,8 +1868,6 @@ event_sched_in(struct perf_event *event,
perf_pmu_disable(event->pmu);
- event->tstamp_running += tstamp - event->tstamp_stopped;
-
perf_set_shadow_time(event, ctx, tstamp);
perf_log_itrace_start(event);
@@ -1881,6 +1879,8 @@ event_sched_in(struct perf_event *event,
goto out;
}
+ event->tstamp_running += tstamp - event->tstamp_stopped;
+
if (!is_software_event(event))
cpuctx->active_oncpu++;
if (!ctx->nr_active++)