Messages in this thread | | | Date | Wed, 03 Apr 2013 14:22:12 +0800 | From | Michael Wang <> | Subject | Re: [patch v3 0/8] sched: use runnable avg in load balance |
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On 04/03/2013 12:28 PM, Alex Shi wrote: > On 04/03/2013 11:23 AM, Michael Wang wrote: >> On 04/03/2013 10:56 AM, Alex Shi wrote: >>> On 04/03/2013 10:46 AM, Michael Wang wrote: [snip] > > > From 4722a7567dccfb19aa5afbb49982ffb6d65e6ae5 Mon Sep 17 00:00:00 2001 > From: Alex Shi <alex.shi@intel.com> > Date: Tue, 2 Apr 2013 10:27:45 +0800 > Subject: [PATCH] sched: use instant load for burst wake up > > If many tasks sleep long time, their runnable load are zero. And if they > are waked up bursty, too light runnable load causes big imbalance among > CPU. So such benchmark, like aim9 drop 5~7%. > > With this patch the losing is covered, and even is slight better.
A fast test show the improvement disappear and the regression back again...after applied this one as the 8th patch, it doesn't works.
Regards, Michael Wang
> > Signed-off-by: Alex Shi <alex.shi@intel.com> > --- > kernel/sched/fair.c | 16 ++++++++++++++-- > 1 file changed, 14 insertions(+), 2 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index dbaa8ca..25ac437 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -3103,12 +3103,24 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync) > unsigned long weight; > int balanced; > int runnable_avg; > + int burst = 0; > > idx = sd->wake_idx; > this_cpu = smp_processor_id(); > prev_cpu = task_cpu(p); > - load = source_load(prev_cpu, idx); > - this_load = target_load(this_cpu, idx); > + > + if (cpu_rq(this_cpu)->avg_idle < sysctl_sched_migration_cost || > + cpu_rq(prev_cpu)->avg_idle < sysctl_sched_migration_cost) > + burst= 1; > + > + /* use instant load for bursty waking up */ > + if (!burst) { > + load = source_load(prev_cpu, idx); > + this_load = target_load(this_cpu, idx); > + } else { > + load = cpu_rq(prev_cpu)->load.weight; > + this_load = cpu_rq(this_cpu)->load.weight; > + } > > /* > * If sync wakeup then subtract the (maximum possible) >
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