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author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2008-06-27 13:41:16 +0200 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-06-27 14:31:31 +0200 |
commit | 103638d95ba5b0c53c8d9c0cb581156ccc8513ee (patch) | |
tree | 56d78e3e00780e044ef7688f27c93ece813035c1 /kernel/sched_fair.c | |
parent | 76a2a6ee8a0660a29127f05989ac59ae1ce865fa (diff) | |
download | kernel_samsung_smdk4412-103638d95ba5b0c53c8d9c0cb581156ccc8513ee.zip kernel_samsung_smdk4412-103638d95ba5b0c53c8d9c0cb581156ccc8513ee.tar.gz kernel_samsung_smdk4412-103638d95ba5b0c53c8d9c0cb581156ccc8513ee.tar.bz2 |
sched: fix wakeup granularity and buddy granularity
Uncouple buddy selection from wakeup granularity.
The initial idea was that buddies could run ahead as far as a normal task
can - do this by measuring a pair 'slice' just as we do for a normal task.
This means we can drop the wakeup_granularity back to 5ms.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched_fair.c')
-rw-r--r-- | kernel/sched_fair.c | 15 |
1 files changed, 7 insertions, 8 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 183388c..509092a 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -63,13 +63,13 @@ unsigned int __read_mostly sysctl_sched_compat_yield; /* * SCHED_OTHER wake-up granularity. - * (default: 10 msec * (1 + ilog(ncpus)), units: nanoseconds) + * (default: 5 msec * (1 + ilog(ncpus)), units: nanoseconds) * * This option delays the preemption effects of decoupled workloads * and reduces their over-scheduling. Synchronous workloads will still * have immediate wakeup/sleep latencies. */ -unsigned int sysctl_sched_wakeup_granularity = 10000000UL; +unsigned int sysctl_sched_wakeup_granularity = 5000000UL; const_debug unsigned int sysctl_sched_migration_cost = 500000UL; @@ -813,17 +813,16 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) se->prev_sum_exec_runtime = se->sum_exec_runtime; } -static int -wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se); - static struct sched_entity * pick_next(struct cfs_rq *cfs_rq, struct sched_entity *se) { - if (!cfs_rq->next) - return se; + struct rq *rq = rq_of(cfs_rq); + u64 pair_slice = rq->clock - cfs_rq->pair_start; - if (wakeup_preempt_entity(cfs_rq->next, se) != 0) + if (!cfs_rq->next || pair_slice > sched_slice(cfs_rq, cfs_rq->next)) { + cfs_rq->pair_start = rq->clock; return se; + } return cfs_rq->next; } |