From b5482cfa1c95a188b3054fa33274806add91bbe5 Mon Sep 17 00:00:00 2001 From: Alex Shi Date: Tue, 16 Nov 2010 17:34:02 +0800 Subject: sched: Fix volanomark performance regression Commit fab4762 triggers excessive idle balancing, causing a ~30% loss in volanomark throughput. Remove idle balancing throttle reset. Originally-by: Alex Shi Signed-off-by: Mike Galbraith Acked-by: Nikhil Rao Signed-off-by: Peter Zijlstra LKML-Reference: <1289928732.5169.211.camel@maggy.simson.net> Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 52ab113d8bb9..ba0556dc7c06 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1758,10 +1758,6 @@ static void pull_task(struct rq *src_rq, struct task_struct *p, set_task_cpu(p, this_cpu); activate_task(this_rq, p, 0); check_preempt_curr(this_rq, p, 0); - - /* re-arm NEWIDLE balancing when moving tasks */ - src_rq->avg_idle = this_rq->avg_idle = 2*sysctl_sched_migration_cost; - this_rq->idle_stamp = 0; } /* -- cgit v1.2.3 From d5ad140bc1505a98c0f040937125bfcbb508078f Mon Sep 17 00:00:00 2001 From: Nikhil Rao Date: Wed, 17 Nov 2010 11:42:04 -0800 Subject: sched: Fix idle balancing An earlier commit reverts idle balancing throttling reset to fix a 30% regression in volanomark throughput. We still need to reset idle_stamp when we pull a task in newidle balance. Reported-by: Alex Shi Signed-off-by: Nikhil Rao Signed-off-by: Peter Zijlstra LKML-Reference: <1290022924-3548-1-git-send-email-ncrao@google.com> Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index ba0556dc7c06..00ebd7686676 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -3215,8 +3215,10 @@ static void idle_balance(int this_cpu, struct rq *this_rq) interval = msecs_to_jiffies(sd->balance_interval); if (time_after(next_balance, sd->last_balance + interval)) next_balance = sd->last_balance + interval; - if (pulled_task) + if (pulled_task) { + this_rq->idle_stamp = 0; break; + } } raw_spin_lock(&this_rq->lock); -- cgit v1.2.3