Messages in this thread Patch in this message |  | | | Subject | Re: [patch 8/12] sched: remove FAIR_SLEEPERS feature | | From | Mike Galbraith <> | | Date | Thu, 11 Mar 2010 10:58:40 +0100 |
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sched: remove FAIR_SLEEPERS feature
Our preemption model relies too heavily on sleeper fairness to disable it without dire consequences. Remove the feature, and save a branch or two.
Signed-off-by: Mike Galbraith <efault@gmx.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission>
--- kernel/sched_fair.c | 2 +- kernel/sched_features.h | 7 ------- 2 files changed, 1 insertion(+), 8 deletions(-) Index: linux-2.6/kernel/sched_fair.c =================================================================== --- linux-2.6.orig/kernel/sched_fair.c +++ linux-2.6/kernel/sched_fair.c @@ -737,7 +737,7 @@ place_entity(struct cfs_rq *cfs_rq, stru vruntime += sched_vslice(cfs_rq, se); /* sleeps up to a single latency don't count. */ - if (!initial && sched_feat(FAIR_SLEEPERS)) { + if (!initial) { unsigned long thresh = sysctl_sched_latency; /* Index: linux-2.6/kernel/sched_features.h =================================================================== --- linux-2.6.orig/kernel/sched_features.h +++ linux-2.6/kernel/sched_features.h @@ -1,11 +1,4 @@ /* - * Disregards a certain amount of sleep time (sched_latency_ns) and - * considers the task to be running during that period. This gives it - * a service deficit on wakeup, allowing it to run sooner. - */ -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.
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