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| author | Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> | 2008-01-31 22:45:22 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-01-31 22:45:22 +0100 |
| commit | 296825cbe14d4c95ee9c41ca5824f7487bfb4d9d (patch) | |
| tree | c1d608ee1dd774f1d726c12873feff8a29422fff | |
| parent | RCU: add help text for "RCU implementation type" (diff) | |
| download | linux-296825cbe14d4c95ee9c41ca5824f7487bfb4d9d.tar.xz linux-296825cbe14d4c95ee9c41ca5824f7487bfb4d9d.zip | |
sched: fix high wake up latencies with FAIR_USER_SCHED
The reason why we are getting better wakeup latencies for
!FAIR_USER_SCHED is because of this snippet of code in place_entity():
if (!initial) {
/* sleeps upto a single latency don't count. */
if (sched_feat(NEW_FAIR_SLEEPERS) && entity_is_task(se))
^^^^^^^^^^^^^^^^^^
vruntime -= sysctl_sched_latency;
/* ensure we never gain time by being placed backwards. */
vruntime = max_vruntime(se->vruntime, vruntime);
}
NEW_FAIR_SLEEPERS feature gives credit for sleeping only to tasks and
not group-level entities. With the patch attached, I could see that
wakeup latencies with FAIR_USER_SCHED are restored to the same level as
!FAIR_USER_SCHED.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | kernel/sched_fair.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 72e25c7a3a18..cf958aefac33 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -520,7 +520,7 @@ 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) && entity_is_task(se)) + if (sched_feat(NEW_FAIR_SLEEPERS)) vruntime -= sysctl_sched_latency; /* ensure we never gain time by being placed backwards. */ |