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From: Peter Zijlstra <peterz@infradead.org>
To: mingo@kernel.org, acme@kernel.org, mark.rutland@arm.com,
	alexander.shishkin@linux.intel.com, jolsa@redhat.com,
	namhyung@kernel.org
Cc: linux-kernel@vger.kernel.org, eranian@google.com,
	ak@linux.intel.com, peterz@infradead.org
Subject: [PATCH v2 3/4] perf: Fix event multiplexing for exclusive groups
Date: Thu, 29 Oct 2020 17:27:22 +0100
Message-ID: <20201029162902.038667689@infradead.org> (raw)
In-Reply-To: <20201029162719.519685265@infradead.org>

Commit 9e6302056f80 ("perf: Use hrtimers for event multiplexing")
placed the hrtimer (re)start call in the wrong place.  Instead of
capturing all scheduling failures, it only considered the PMU failure.

The result is that groups using perf_event_attr::exclusive are no
longer rotated.

Fixes: 9e6302056f80 ("perf: Use hrtimers for event multiplexing")
Reported-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 kernel/events/core.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -2612,7 +2612,6 @@ group_sched_in(struct perf_event *group_
 
 error:
 	pmu->cancel_txn(pmu);
-	perf_mux_hrtimer_restart(cpuctx);
 	return -EAGAIN;
 }
 
@@ -3672,6 +3671,7 @@ static int merge_sched_in(struct perf_ev
 
 		*can_add_hw = 0;
 		ctx->rotate_necessary = 1;
+		perf_mux_hrtimer_restart(cpuctx);
 	}
 
 	return 0;



  parent reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-29 16:27 [PATCH v2 0/4] perf: Fix perf_event_attr::exclusive rotation Peter Zijlstra
2020-10-29 16:27 ` [PATCH v2 1/4] perf: Simplify group_sched_out() Peter Zijlstra
2020-11-10 12:45   ` [tip: perf/urgent] " tip-bot2 for Peter Zijlstra
2020-10-29 16:27 ` [PATCH v2 2/4] perf: Simplify group_sched_in() Peter Zijlstra
2020-11-10 12:45   ` [tip: perf/urgent] " tip-bot2 for Peter Zijlstra
2020-10-29 16:27 ` Peter Zijlstra [this message]
2020-11-10 12:45   ` [tip: perf/urgent] perf: Fix event multiplexing for exclusive groups tip-bot2 for Peter Zijlstra
2020-10-29 16:27 ` [PATCH v2 4/4] perf: Tweak perf_event_attr::exclusive semantics Peter Zijlstra
2020-11-10 12:45   ` [tip: perf/urgent] " tip-bot2 for Peter Zijlstra
2020-10-31 23:44 ` [PATCH v2 0/4] perf: Fix perf_event_attr::exclusive rotation Jiri Olsa
2020-11-02  3:52   ` Andi Kleen
2020-11-02 14:16     ` Peter Zijlstra
2020-11-03  2:41       ` Andi Kleen
2020-11-09 11:48         ` Peter Zijlstra

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