From: Peter Zijlstra Date: Mon, 27 Jul 2015 08:35:07 +0000 (+0200) Subject: perf: Fix running time accounting X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=00a2916f7f82c348a2a94dbb572874173bc308a3;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git 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 --- 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++)