Messages in this thread Patch in this message | | | Date | Thu, 22 May 2014 05:29:23 -0700 | From | tip-bot for Rik van Riel <> | Subject | [tip:sched/core] sched/numa: Decay -> wakee_flips instead of zeroing |
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Commit-ID: 096aa33863a5e48de52d2ff30e0801b7487944f4 Gitweb: http://git.kernel.org/tip/096aa33863a5e48de52d2ff30e0801b7487944f4 Author: Rik van Riel <riel@redhat.com> AuthorDate: Fri, 16 May 2014 00:13:32 -0400 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Thu, 22 May 2014 11:16:41 +0200
sched/numa: Decay ->wakee_flips instead of zeroing
Affine wakeups have the potential to interfere with NUMA placement. If a task wakes up too many other tasks, affine wakeups will get disabled.
However, regardless of how many other tasks it wakes up, it gets re-enabled once a second, potentially interfering with NUMA placement of other tasks.
By decaying wakee_wakes in half instead of zeroing it, we can avoid that problem for some workloads.
Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: chegu_vinod@hp.com Cc: umgwanakikbuti@gmail.com Link: http://lkml.kernel.org/r/20140516001332.67f91af2@annuminas.surriel.com Signed-off-by: Ingo Molnar <mingo@kernel.org> --- kernel/sched/fair.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 503f750..c9617b7 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4065,7 +4065,7 @@ static void record_wakee(struct task_struct *p) * about the loss. */ if (jiffies > current->wakee_flip_decay_ts + HZ) { - current->wakee_flips = 0; + current->wakee_flips >>= 1; current->wakee_flip_decay_ts = jiffies; }
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