From 096aa33863a5e48de52d2ff30e0801b7487944f4 Mon Sep 17 00:00:00 2001 From: Rik van Riel Date: Fri, 16 May 2014 00:13:32 -0400 Subject: [PATCH] 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 Signed-off-by: Peter Zijlstra 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 --- 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; } -- 2.7.4