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| author | Peter Zijlstra <peterz@infradead.org> | 2021-03-25 15:44:46 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2021-04-16 18:06:35 +0300 |
| commit | 0c2de3f054a59f15e01804b75a04355c48de628c (patch) | |
| tree | cacb2c2f2ad3711dac0212cc31dbdbedda6552f2 | |
| parent | d27e9ae2f244805bbdc730d85fba28685d2471e5 (diff) | |
| download | linux-0c2de3f054a59f15e01804b75a04355c48de628c.tar.xz | |
sched,fair: Alternative sched_slice()
The current sched_slice() seems to have issues; there's two possible
things that could be improved:
- the 'nr_running' used for __sched_period() is daft when cgroups are
considered. Using the RQ wide h_nr_running seems like a much more
consistent number.
- (esp) cgroups can slice it real fine, which makes for easy
over-scheduling, ensure min_gran is what the name says.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Valentin Schneider <valentin.schneider@arm.com>
Link: https://lkml.kernel.org/r/20210412102001.611897312@infradead.org
| -rw-r--r-- | kernel/sched/fair.c | 12 | ||||
| -rw-r--r-- | kernel/sched/features.h | 3 |
2 files changed, 14 insertions, 1 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index b3ea14c08a9b..49636a49843f 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -687,7 +687,13 @@ static u64 __sched_period(unsigned long nr_running) */ static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se) { - u64 slice = __sched_period(cfs_rq->nr_running + !se->on_rq); + unsigned int nr_running = cfs_rq->nr_running; + u64 slice; + + if (sched_feat(ALT_PERIOD)) + nr_running = rq_of(cfs_rq)->cfs.h_nr_running; + + slice = __sched_period(nr_running + !se->on_rq); for_each_sched_entity(se) { struct load_weight *load; @@ -704,6 +710,10 @@ static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se) } slice = __calc_delta(slice, se->load.weight, load); } + + if (sched_feat(BASE_SLICE)) + slice = max(slice, (u64)sysctl_sched_min_granularity); + return slice; } diff --git a/kernel/sched/features.h b/kernel/sched/features.h index 422fa68c0ee9..011c5ec7b7b5 100644 --- a/kernel/sched/features.h +++ b/kernel/sched/features.h @@ -90,3 +90,6 @@ SCHED_FEAT(WA_BIAS, true) */ SCHED_FEAT(UTIL_EST, true) SCHED_FEAT(UTIL_EST_FASTUP, true) + +SCHED_FEAT(ALT_PERIOD, true) +SCHED_FEAT(BASE_SLICE, true) |