From 00a2916f7f82c348a2a94dbb572874173bc308a3 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 27 Jul 2015 10:35:07 +0200 Subject: [PATCH] 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 Fixes: 72f669c0086f ("perf: Update shadow timestamp before add event") Signed-off-by: Peter Zijlstra (Intel) Cc: stable@vger.kernel.org # 4.1 Cc: Shaohua Li Signed-off-by: Thomas Gleixner --- kernel/events/core.c | 4 ++-- 1 file 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++) -- 2.20.1