On Thu, 8 Oct 2015 15:36:06 -0300 Daniel Bristot de Oliveira <bris...@redhat.com> wrote:
> 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 <bris...@redhat.com> > Reviewed-by: Luis Claudio R. Goncalves <lgonc...@redhat.com> Acked-by: Steven Rostedt <rost...@goodmis.org> -- Steve > --- > kernel/sched/idle.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c > index 8f177c7..4a2ef5a 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; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
