4.1-stable review patch. If anyone has any objections, please let me know.
------------------ From: Peter Zijlstra <[email protected]> commit 00a2916f7f82c348a2a94dbb572874173bc308a3 upstream. 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 <[email protected]> Fixes: 72f669c0086f ("perf: Update shadow timestamp before add event") Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Cc: Shaohua Li <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- kernel/events/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1886,8 +1886,6 @@ 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); @@ -1899,6 +1897,8 @@ 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++) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
