From: peterz@infradead•org (Peter Zijlstra)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v2 10/11] sched: move cfs task on a CPU with higher capacity
Date: Fri, 30 May 2014 08:29:37 +0200 [thread overview]
Message-ID: <20140530062937.GA11096@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <CAKfTPtCHhxyugMOCeS0hZoEXWhgRec4uOBexZ2aB2A+Eycgi8w@mail.gmail.com>
On Thu, May 29, 2014 at 09:37:39PM +0200, Vincent Guittot wrote:
> On 29 May 2014 11:50, Peter Zijlstra <peterz@infradead•org> wrote:
> > On Fri, May 23, 2014 at 05:53:04PM +0200, Vincent Guittot wrote:
> >> If the CPU is used for handling lot of IRQs, trig a load balance to check if
> >> it's worth moving its tasks on another CPU that has more capacity
> >>
> >> Signed-off-by: Vincent Guittot <vincent.guittot@linaro•org>
> >> ---
> >> kernel/sched/fair.c | 13 +++++++++++++
> >> 1 file changed, 13 insertions(+)
> >>
> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> >> index e8a30f9..2501e49 100644
> >> --- a/kernel/sched/fair.c
> >> +++ b/kernel/sched/fair.c
> >> @@ -5948,6 +5948,13 @@ static bool update_sd_pick_busiest(struct lb_env *env,
> >> if (sgs->sum_nr_running > sgs->group_capacity)
> >> return true;
> >>
> >> + /*
> >> + * The group capacity is reduced probably because of activity from other
> >> + * sched class or interrupts which use part of the available capacity
> >> + */
> >> + if ((sg->sgp->power_orig * 100) > (sgs->group_power * env->sd->imbalance_pct))
> >> + return true;
> >> +
> >> if (sgs->group_imb)
> >> return true;
> >>
> >
> > But we should already do this because the load numbers are scaled with
> > the power/capacity figures. If one CPU gets significant less time to run
> > fair tasks, its effective load would spike and it'd get to be selected
> > here anyway.
> >
> > Or am I missing something?
>
> The CPU could have been picked when the capacity becomes null (which
> occurred when the cpu_power goes below half the default
> SCHED_POWER_SCALE). And even after that, there were some conditions in
> find_busiest_group that was bypassing this busiest group
Could you detail those conditions? FWIW those make excellent Changelog
material.
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next prev parent reply other threads:[~2014-05-30 6:29 UTC|newest]
Thread overview: 108+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-23 15:52 [PATCH v2 00/11] sched: consolidation of cpu_power Vincent Guittot
2014-05-23 15:52 ` [PATCH v2 01/11] sched: fix imbalance flag reset Vincent Guittot
2014-05-25 10:33 ` Preeti U Murthy
2014-05-26 7:49 ` Vincent Guittot
2014-05-26 9:16 ` Preeti U Murthy
2014-05-26 10:14 ` Vincent Guittot
2014-05-23 15:52 ` [PATCH v2 02/11] sched: remove a wake_affine condition Vincent Guittot
2014-05-27 12:48 ` Peter Zijlstra
2014-05-27 15:19 ` Vincent Guittot
2014-05-27 15:39 ` Peter Zijlstra
2014-05-27 16:14 ` Vincent Guittot
2014-05-28 6:49 ` Vincent Guittot
2014-05-28 15:09 ` Dietmar Eggemann
2014-05-28 15:25 ` Vincent Guittot
2014-05-27 13:43 ` Peter Zijlstra
2014-05-27 13:45 ` Peter Zijlstra
2014-05-27 15:20 ` Vincent Guittot
2014-05-23 15:52 ` [PATCH v2 03/11] sched: fix avg_load computation Vincent Guittot
2014-05-27 13:48 ` Peter Zijlstra
2014-05-23 15:52 ` [PATCH v2 04/11] sched: Allow all archs to set the power_orig Vincent Guittot
2014-05-30 14:04 ` Dietmar Eggemann
2014-05-30 14:46 ` Peter Zijlstra
2014-05-30 20:50 ` Vincent Guittot
2014-06-04 9:42 ` Dietmar Eggemann
2014-06-04 11:15 ` Vincent Guittot
2014-06-05 8:59 ` Dietmar Eggemann
2014-06-16 9:01 ` Vincent Guittot
2014-06-03 13:22 ` Morten Rasmussen
2014-06-03 14:02 ` Vincent Guittot
2014-06-04 11:17 ` Morten Rasmussen
2014-06-06 7:01 ` Vincent Guittot
2014-05-23 15:52 ` [PATCH v2 05/11] ARM: topology: use new cpu_power interface Vincent Guittot
2014-05-25 13:22 ` Preeti U Murthy
2014-05-26 8:25 ` Vincent Guittot
2014-05-26 9:19 ` Preeti U Murthy
2014-05-23 15:53 ` [PATCH v2 06/11] sched: add per rq cpu_power_orig Vincent Guittot
2014-05-23 15:53 ` [PATCH v2 07/11] Revert "sched: Put rq's sched_avg under CONFIG_FAIR_GROUP_SCHED" Vincent Guittot
2014-05-23 15:53 ` [PATCH v2 08/11] sched: get CPU's activity statistic Vincent Guittot
2014-05-27 17:32 ` Peter Zijlstra
2014-05-28 7:01 ` Vincent Guittot
2014-05-28 12:10 ` Morten Rasmussen
2014-05-28 13:15 ` Vincent Guittot
2014-05-28 15:47 ` Morten Rasmussen
2014-05-28 16:39 ` Vincent Guittot
2014-06-03 12:03 ` Morten Rasmussen
2014-06-03 15:59 ` Peter Zijlstra
2014-06-03 17:41 ` Morten Rasmussen
2014-06-03 15:50 ` Peter Zijlstra
2014-06-03 17:20 ` Morten Rasmussen
2014-06-04 7:47 ` Vincent Guittot
2014-06-04 8:08 ` Peter Zijlstra
2014-06-04 8:55 ` Morten Rasmussen
2014-06-04 9:23 ` Peter Zijlstra
2014-06-04 9:35 ` Vincent Guittot
2014-06-04 10:25 ` Morten Rasmussen
2014-06-04 9:44 ` Morten Rasmussen
2014-06-04 9:32 ` Vincent Guittot
2014-06-04 10:00 ` Morten Rasmussen
2014-06-04 10:17 ` Peter Zijlstra
2014-06-04 10:36 ` Morten Rasmussen
2014-06-04 10:55 ` Peter Zijlstra
2014-06-04 11:07 ` Vincent Guittot
2014-06-04 11:23 ` Morten Rasmussen
2014-06-04 11:52 ` Vincent Guittot
2014-06-04 13:09 ` Morten Rasmussen
2014-06-04 13:23 ` Morten Rasmussen
2014-05-28 15:17 ` Peter Zijlstra
2014-06-03 15:40 ` Peter Zijlstra
2014-06-03 17:16 ` Morten Rasmussen
2014-06-03 17:37 ` Peter Zijlstra
2014-06-03 17:39 ` Peter Zijlstra
2014-06-03 23:11 ` Yuyang Du
2014-05-30 9:50 ` Dietmar Eggemann
2014-05-30 19:20 ` Vincent Guittot
2014-06-01 11:33 ` Dietmar Eggemann
2014-06-02 14:07 ` Vincent Guittot
2014-05-23 15:53 ` [PATCH v2 09/11] sched: test the cpu's capacity in wake affine Vincent Guittot
2014-05-28 10:58 ` Peter Zijlstra
2014-05-28 11:15 ` Vincent Guittot
2014-11-24 0:34 ` Wanpeng Li
2014-11-24 13:23 ` Vincent Guittot
2014-05-23 15:53 ` [PATCH v2 10/11] sched: move cfs task on a CPU with higher capacity Vincent Guittot
2014-05-29 9:50 ` Peter Zijlstra
2014-05-29 19:37 ` Vincent Guittot
2014-05-30 6:29 ` Peter Zijlstra [this message]
2014-05-30 20:05 ` Vincent Guittot
2014-06-02 17:06 ` Vincent Guittot
2014-06-03 11:15 ` Peter Zijlstra
2014-06-03 12:31 ` Vincent Guittot
2014-05-29 14:04 ` Peter Zijlstra
2014-05-29 19:44 ` Vincent Guittot
2014-05-30 13:26 ` Dietmar Eggemann
2014-05-30 19:24 ` Vincent Guittot
2014-05-30 19:45 ` Nicolas Pitre
2014-05-30 20:07 ` Vincent Guittot
2014-05-23 15:53 ` [PATCH v2 11/11] sched: replace capacity by activity Vincent Guittot
2014-05-29 13:55 ` Peter Zijlstra
2014-05-29 19:51 ` Vincent Guittot
2014-06-02 6:21 ` Preeti U Murthy
2014-06-03 9:50 ` Vincent Guittot
2014-05-29 14:02 ` Peter Zijlstra
2014-05-29 19:56 ` Vincent Guittot
2014-05-30 6:34 ` Peter Zijlstra
2014-05-30 19:13 ` Vincent Guittot
2014-05-26 9:44 ` [PATCH v2 00/11] sched: consolidation of cpu_power Preeti U Murthy
2014-05-26 10:04 ` Vincent Guittot
2014-05-26 15:54 ` Vincent Guittot
2014-05-27 5:47 ` Preeti U Murthy
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