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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-03-07 14:42:34 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-03-07 14:42:34 -0800 |
| commit | 609b07b72d3caaa8eed3a238886467946b78fa5e (patch) | |
| tree | b12ee470ed68675b3bbe4c0dcfa63a9978821fce /kernel/sched | |
| parent | c3abcabe813b4a0976b58f7e6c1e63b2070c8dda (diff) | |
| parent | f94c8d116997597fc00f0812b0ab9256e7b0c58f (diff) | |
Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
"A fix for KVM's scheduler clock which (erroneously) was always marked
unstable, a fix for RT/DL load balancing, plus latency fixes"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/clock, x86/tsc: Rework the x86 'unstable' sched_clock() interface
sched/core: Fix pick_next_task() for RT,DL
sched/fair: Make select_idle_cpu() more aggressive
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/core.c | 11 | ||||
| -rw-r--r-- | kernel/sched/fair.c | 2 | ||||
| -rw-r--r-- | kernel/sched/features.h | 5 |
3 files changed, 14 insertions, 4 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 956383844116..3b31fc05a0f1 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3287,10 +3287,15 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) struct task_struct *p; /* - * Optimization: we know that if all tasks are in - * the fair class we can call that function directly: + * Optimization: we know that if all tasks are in the fair class we can + * call that function directly, but only if the @prev task wasn't of a + * higher scheduling class, because otherwise those loose the + * opportunity to pull in more work from other CPUs. */ - if (likely(rq->nr_running == rq->cfs.h_nr_running)) { + if (likely((prev->sched_class == &idle_sched_class || + prev->sched_class == &fair_sched_class) && + rq->nr_running == rq->cfs.h_nr_running)) { + p = fair_sched_class.pick_next_task(rq, prev, rf); if (unlikely(p == RETRY_TASK)) goto again; diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 3e88b35ac157..dea138964b91 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5799,7 +5799,7 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int t * Due to large variance we need a large fuzz factor; hackbench in * particularly is sensitive here. */ - if ((avg_idle / 512) < avg_cost) + if (sched_feat(SIS_AVG_CPU) && (avg_idle / 512) < avg_cost) return -1; time = local_clock(); diff --git a/kernel/sched/features.h b/kernel/sched/features.h index 69631fa46c2f..1b3c8189b286 100644 --- a/kernel/sched/features.h +++ b/kernel/sched/features.h @@ -51,6 +51,11 @@ SCHED_FEAT(NONTASK_CAPACITY, true) */ SCHED_FEAT(TTWU_QUEUE, true) +/* + * When doing wakeups, attempt to limit superfluous scans of the LLC domain. + */ +SCHED_FEAT(SIS_AVG_CPU, false) + #ifdef HAVE_RT_PUSH_IPI /* * In order to avoid a thundering herd attack of CPUs that are |