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authorPeter Zijlstra <peterz@infradead.org>2009-09-16 14:31:31 +0400
committerIngo Molnar <mingo@elte.hu>2009-09-17 12:17:25 +0400
commitad4b78bbcbab66998b05d422ac6106b645796e54 (patch)
tree45f3561f4bd6b886948a3b0eea64edab9bab9eda /kernel/sched_features.h
parenteb24073bc1fe3e569a855cf38d529fb650c35524 (diff)
downloadlinux-ad4b78bbcbab66998b05d422ac6106b645796e54.tar.xz
sched: Add new wakeup preemption mode: WAKEUP_RUNNING
Create a new wakeup preemption mode, preempt towards tasks that run shorter on avg. It sets next buddy to be sure we actually run the task we preempted for. Test results: root@twins:~# while :; do :; done & [1] 6537 root@twins:~# while :; do :; done & [2] 6538 root@twins:~# while :; do :; done & [3] 6539 root@twins:~# while :; do :; done & [4] 6540 root@twins:/home/peter# ./latt -c4 sleep 4 Entries: 48 (clients=4) Averages: ------------------------------ Max 4750 usec Avg 497 usec Stdev 737 usec root@twins:/home/peter# echo WAKEUP_RUNNING > /debug/sched_features root@twins:/home/peter# ./latt -c4 sleep 4 Entries: 48 (clients=4) Averages: ------------------------------ Max 14 usec Avg 5 usec Stdev 3 usec Disabled by default - needs more testing. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> LKML-Reference: <new-submission>
Diffstat (limited to 'kernel/sched_features.h')
-rw-r--r--kernel/sched_features.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/sched_features.h b/kernel/sched_features.h
index d5059fd761d9..0d94083582c7 100644
--- a/kernel/sched_features.h
+++ b/kernel/sched_features.h
@@ -54,6 +54,11 @@ SCHED_FEAT(WAKEUP_SYNC, 0)
SCHED_FEAT(WAKEUP_OVERLAP, 0)
/*
+ * Wakeup preemption towards tasks that run short
+ */
+SCHED_FEAT(WAKEUP_RUNNING, 0)
+
+/*
* Use the SYNC wakeup hint, pipes and the likes use this to indicate
* the remote end is likely to consume the data we just wrote, and
* therefore has cache benefit from being placed on the same cpu, see