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author | Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> | 2008-01-31 22:45:22 +0100 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-01-31 22:45:22 +0100 |
commit | 296825cbe14d4c95ee9c41ca5824f7487bfb4d9d (patch) | |
tree | c1d608ee1dd774f1d726c12873feff8a29422fff /kernel/sched.c | |
parent | 095031052b4c03a7c8ffa51cbab031e442c4f8b7 (diff) | |
download | lwn-296825cbe14d4c95ee9c41ca5824f7487bfb4d9d.tar.gz lwn-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>
Diffstat (limited to 'kernel/sched.c')
0 files changed, 0 insertions, 0 deletions