| Subject: sched: Disable TTWU_QUEUE on RT |
| From: Thomas Gleixner <tglx@linutronix.de> |
| Date: Tue, 13 Sep 2011 16:42:35 +0200 |
| |
| The queued remote wakeup mechanism can introduce rather large |
| latencies if the number of migrated tasks is high. Disable it for RT. |
| |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| --- |
| kernel/sched/features.h | 5 +++++ |
| 1 file changed, 5 insertions(+) |
| |
| --- a/kernel/sched/features.h |
| +++ b/kernel/sched/features.h |
| @@ -45,11 +45,16 @@ SCHED_FEAT(LB_BIAS, true) |
| */ |
| SCHED_FEAT(NONTASK_CAPACITY, true) |
| |
| +#ifdef CONFIG_PREEMPT_RT_FULL |
| +SCHED_FEAT(TTWU_QUEUE, false) |
| +#else |
| + |
| /* |
| * Queue remote wakeups on the target CPU and process them |
| * using the scheduler IPI. Reduces rq->lock contention/bounces. |
| */ |
| SCHED_FEAT(TTWU_QUEUE, true) |
| +#endif |
| |
| #ifdef HAVE_RT_PUSH_IPI |
| /* |
