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| author | Ingo Molnar <mingo@elte.hu> | 2009-09-16 08:54:45 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-09-16 09:05:20 +0200 |
| commit | 51e0304ce6e55a6e59658558916b4f74da085ff0 (patch) | |
| tree | da17f8f9f1b3b0431cd0cd1e90ea95f970654f9f | |
| parent | sched: Add SD_PREFER_LOCAL (diff) | |
| download | linux-51e0304ce6e55a6e59658558916b4f74da085ff0.tar.xz linux-51e0304ce6e55a6e59658558916b4f74da085ff0.zip | |
sched: Implement a gentler fair-sleepers feature
Add back FAIR_SLEEPERS and GENTLE_FAIR_SLEEPERS.
FAIR_SLEEPERS is the old logic: credit sleepers with their sleep time.
GENTLE_FAIR_SLEEPERS dampens this a bit: 50% of their sleep time gets
credited.
The hope here is to still give the benefits of fair-sleepers logic
(quick wakeups, etc.) while not allow them to have 100% of their
sleep time as if they were running.
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | kernel/sched_fair.c | 9 | ||||
| -rw-r--r-- | kernel/sched_features.h | 9 |
2 files changed, 16 insertions, 2 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index a37f311f436e..acf16a8d934b 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -711,7 +711,7 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial) if (!initial) { /* sleeps upto a single latency don't count. */ - if (sched_feat(NEW_FAIR_SLEEPERS)) { + if (sched_feat(FAIR_SLEEPERS)) { unsigned long thresh = sysctl_sched_latency; /* @@ -725,6 +725,13 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial) task_of(se)->policy != SCHED_IDLE)) thresh = calc_delta_fair(thresh, se); + /* + * Halve their sleep time's effect, to allow + * for a gentler effect of sleepers: + */ + if (sched_feat(GENTLE_FAIR_SLEEPERS)) + thresh >>= 1; + vruntime -= thresh; } } diff --git a/kernel/sched_features.h b/kernel/sched_features.h index 70115c69c7a9..fd375675f834 100644 --- a/kernel/sched_features.h +++ b/kernel/sched_features.h @@ -3,7 +3,14 @@ * considers the task to be running during that period. This gives it * a service deficit on wakeup, allowing it to run sooner. */ -SCHED_FEAT(NEW_FAIR_SLEEPERS, 0) +SCHED_FEAT(FAIR_SLEEPERS, 1) + +/* + * Only give sleepers 50% of their service deficit. This allows + * them to run sooner, but does not allow tons of sleepers to + * rip the spread apart. + */ +SCHED_FEAT(GENTLE_FAIR_SLEEPERS, 1) /* * By not normalizing the sleep time, heavy tasks get an effective |