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authorJason Low2013-09-13 11:26:51 -0700
committerIngo Molnar2013-09-20 12:03:41 +0200
commitabfafa54db9aba404e8e6763503f04d35bd07138 (patch)
tree64a965459a5de970ff15265a9cd9f436591cadde
parent7aff2e3a56b724b79fa2d5abd10d8231ef8fb0c5 (diff)
sched: Reduce overestimating rq->avg_idle
When updating avg_idle, if the delta exceeds some max value, then avg_idle gets set to the max, regardless of what the previous avg was. This can cause avg_idle to often be overestimated. This patch modifies the way we update avg_idle by always updating it with the function call to update_avg() first. Then, if avg_idle exceeds the max, we set it to the max. Signed-off-by: Jason Low <jason.low2@hp.com> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1379096813-3032-2-git-send-email-jason.low2@hp.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--kernel/sched/core.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5ac63c9a995a..048f39e45761 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1332,10 +1332,11 @@ ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags)
u64 delta = rq_clock(rq) - rq->idle_stamp;
u64 max = 2*sysctl_sched_migration_cost;
- if (delta > max)
+ update_avg(&rq->avg_idle, delta);
+
+ if (rq->avg_idle > max)
rq->avg_idle = max;
- else
- update_avg(&rq->avg_idle, delta);
+
rq->idle_stamp = 0;
}
#endif