Patch "perf: Fix running time accounting" has been added to the 4.1-stable tree

This is a note to let you know that I've just added the patch titled

perf: Fix running time accounting

to the 4.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
perf-fix-running-time-accounting.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Peter Zijlstra <[email protected]>
Date: Mon, 27 Jul 2015 10:35:07 +0200
Subject: perf: Fix running time accounting

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).

---
 kernel/events/core.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

@@ -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++)

Patches currently in stable-queue which might be from [email protected] are

queue-4.1/perf-fix-perf_event_ioc_period-migration-race.patch queue-4.1/ipc-sem.c-update-correct-memory-barriers.patch queue-4.1/perf-fix-fasync-handling-on-inherited-events.patch queue-4.1/perf-fix-double-free-of-the-aux-buffer.patch queue-4.1/perf-fix-running-time-accounting.patch