Commit-ID: 096aa33863a5e48de52d2ff30e0801b7487944f4
Gitweb: http://git.kernel.org/tip/096aa33863a5e48de52d2ff30e0801b7487944f4
Author: Rik van Riel <riel@xxxxxxxxxx>
AuthorDate: Fri, 16 May 2014 00:13:32 -0400
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: chegu_vinod@xxxxxx
Cc: umgwanakikbuti@xxxxxxxxx
Link: http://lkml.kernel.org/r/20140516001332.67f91af2@xxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
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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