From 54f4407608c59712a8f5ec1e10dfac40bef5a2e7 Mon Sep 17 00:00:00 2001
From: Soeren Sandmann <sandmann@daimi.au.dk>
Date: Thu, 22 Oct 2009 18:34:08 +0200
Subject: perf events: Don't generate events for the idle task when
 exclude_idle is set
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Getting samples for the idle task is often not interesting, so
don't generate them when exclude_idle is set for the event in
question.

Signed-off-by: Søren Sandmann Pedersen <sandmann@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <ye8pr8fmlq7.fsf@camel16.daimi.au.dk>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/perf_event.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

(limited to 'kernel')

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 33ff019f9aa6..7f29643c8985 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -3959,8 +3959,9 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
 		regs = task_pt_regs(current);
 
 	if (regs) {
-		if (perf_event_overflow(event, 0, &data, regs))
-			ret = HRTIMER_NORESTART;
+		if (!(event->attr.exclude_idle && current->pid == 0))
+			if (perf_event_overflow(event, 0, &data, regs))
+				ret = HRTIMER_NORESTART;
 	}
 
 	period = max_t(u64, 10000, event->hw.sample_period);
-- 
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