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authorDaniel Bristot de Oliveira <bristot@redhat.com>2015-10-08 15:36:06 -0300
committerIngo Molnar <mingo@kernel.org>2015-10-12 09:45:25 +0200
commit9babcd7929bc8967ae3bb6093f603b93c2f9958f (patch)
treeafcc5d2325bd494c484b828914517680ac7d3316 /kernel/sched
parent25cb62b76430a91cc6195f902e61c2cb84ade622 (diff)
sched, tracing: Stop/start critical timings around the idle=poll idle loop
When using idle=poll, the preemptoff tracer is always showing the idle task as the culprit for long latencies. That happens because critical timings are not stopped before idle loop. This patch stops critical timings before entering the idle loop, starting it again after the idle loop. This problem does not affect the irqsoff tracer because interruptions are enabled before entering the idle loop. Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com> Reviewed-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/10fc3705874aef11dbe152a068b591a7be1899b4.1444314899.git.bristot@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/idle.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 8f177c73ae19..4a2ef5a02fd3 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -57,9 +57,11 @@ static inline int cpu_idle_poll(void)
rcu_idle_enter();
trace_cpu_idle_rcuidle(0, smp_processor_id());
local_irq_enable();
+ stop_critical_timings();
while (!tif_need_resched() &&
(cpu_idle_force_poll || tick_check_broadcast_expired()))
cpu_relax();
+ start_critical_timings();
trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id());
rcu_idle_exit();
return 1;