From: Mike Galbraith <umgwanakikbuti@gmail.com>
To: Josef Bacik <jbacik@fb.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
riel@redhat.com, mingo@redhat.com, linux-kernel@vger.kernel.org,
morten.rasmussen@arm.com
Subject: Re: [PATCH RESEND] sched: prefer an idle cpu vs an idle sibling for BALANCE_WAKE
Date: Thu, 18 Jun 2015 06:12:45 +0200 [thread overview]
Message-ID: <1434600765.3393.9.camel@gmail.com> (raw)
In-Reply-To: <55823F33.7040005@fb.com>
On Wed, 2015-06-17 at 20:46 -0700, Josef Bacik wrote:
> On 06/17/2015 05:55 PM, Mike Galbraith wrote:
> > On Wed, 2015-06-17 at 11:06 -0700, Josef Bacik wrote:
> >> On 06/11/2015 10:35 PM, Mike Galbraith wrote:
> >>> On Thu, 2015-05-28 at 13:05 +0200, Peter Zijlstra wrote:
> >
> >>> If sd == NULL, we fall through and try to pull wakee despite nacked-by
> >>> tsk_cpus_allowed() or wake_affine().
> >>>
> >>
> >> So maybe add a check in the if (sd_flag & SD_BALANCE_WAKE) for something
> >> like this
> >>
> >> if (tmp >= 0) {
> >> new_cpu = tmp;
> >> goto unlock;
> >> } else if (!want_affine) {
> >> new_cpu = prev_cpu;
> >> }
> >>
> >> so we can make sure we're not being pushed onto a cpu that we aren't
> >> allowed on? Thanks,
> >
> > The buglet is a messenger methinks. You saying the patch helped without
> > SD_BALANCE_WAKE being set is why I looked. The buglet would seem to say
> > that preferring cache is not harming your load after all. It now sounds
> > as though wake_wide() may be what you're squabbling with.
> >
> > Things aren't adding up all that well.
>
> Yeah I'm horribly confused. The other thing is I had to switch clusters
> (I know, I know, I'm changing the parameters of the test). So these new
> boxes are haswell boxes, but basically the same otherwise, 2 socket 12
> core with HT, just newer/faster CPUs. I'll re-run everything again and
> give the numbers so we're all on the same page again, but as it stands
> now I think we have this
>
> 3.10 with wake_idle forward ported - good
> 4.0 stock - 20% perf drop
> 4.0 w/ Peter's patch - good
> 4.0 w/ Peter's patch + SD_BALANCE_WAKE - 5% perf drop
>
> I can do all these iterations again to verify, is there any other
> permutation you'd like to see? Thanks,
Yeah, after re-baseline, please apply/poke these buttons individually in
4.0-virgin.
(cat /sys/kernel/debug/sched_features, prepend NO_, echo it back)
---
kernel/sched/fair.c | 4 ++--
kernel/sched/features.h | 2 ++
2 files changed, 4 insertions(+), 2 deletions(-)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4506,7 +4506,7 @@ static int wake_affine(struct sched_doma
* If we wake multiple tasks be careful to not bounce
* ourselves around too much.
*/
- if (wake_wide(p))
+ if (sched_feat(WAKE_WIDE) && wake_wide(p))
return 0;
idx = sd->wake_idx;
@@ -4682,7 +4682,7 @@ static int select_idle_sibling(struct ta
struct sched_group *sg;
int i = task_cpu(p);
- if (idle_cpu(target))
+ if (!sched_feat(PREFER_IDLE) || idle_cpu(target))
return target;
/*
--- a/kernel/sched/features.h
+++ b/kernel/sched/features.h
@@ -59,6 +59,8 @@ SCHED_FEAT(TTWU_QUEUE, true)
SCHED_FEAT(FORCE_SD_OVERLAP, false)
SCHED_FEAT(RT_RUNTIME_SHARE, true)
SCHED_FEAT(LB_MIN, false)
+SCHED_FEAT(PREFER_IDLE, true)
+SCHED_FEAT(WAKE_WIDE, true)
/*
* Apply the automatic NUMA scheduling policy. Enabled automatically
next prev parent reply other threads:[~2015-06-18 4:12 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-27 21:22 [PATCH RESEND] sched: prefer an idle cpu vs an idle sibling for BALANCE_WAKE Josef Bacik
2015-05-28 3:46 ` Mike Galbraith
2015-05-28 9:49 ` Morten Rasmussen
2015-05-28 10:57 ` Mike Galbraith
2015-05-28 11:48 ` Morten Rasmussen
2015-05-28 11:49 ` Mike Galbraith
2015-05-28 10:21 ` Peter Zijlstra
2015-05-28 11:05 ` Peter Zijlstra
2015-05-28 14:27 ` Josef Bacik
2015-05-29 21:03 ` Josef Bacik
2015-05-30 3:55 ` Mike Galbraith
2015-06-01 19:38 ` Josef Bacik
2015-06-01 20:42 ` Peter Zijlstra
2015-06-01 21:03 ` Josef Bacik
2015-06-02 17:12 ` Josef Bacik
2015-06-03 14:12 ` Rik van Riel
2015-06-03 14:24 ` Peter Zijlstra
2015-06-03 14:49 ` Josef Bacik
2015-06-03 15:30 ` Mike Galbraith
2015-06-03 15:57 ` Josef Bacik
2015-06-03 16:53 ` Mike Galbraith
2015-06-03 17:16 ` Josef Bacik
2015-06-03 17:43 ` Mike Galbraith
2015-06-03 20:34 ` Josef Bacik
2015-06-04 4:52 ` Mike Galbraith
2015-06-01 22:15 ` Rik van Riel
2015-06-11 20:33 ` Josef Bacik
2015-06-12 3:42 ` Rik van Riel
2015-06-12 5:35 ` Mike Galbraith
2015-06-17 18:06 ` Josef Bacik
2015-06-18 0:55 ` Mike Galbraith
2015-06-18 3:46 ` Josef Bacik
2015-06-18 4:12 ` Mike Galbraith [this message]
2015-07-02 17:44 ` Josef Bacik
2015-07-03 6:40 ` Mike Galbraith
2015-07-03 9:29 ` Mike Galbraith
2015-07-04 15:57 ` Mike Galbraith
2015-07-05 7:17 ` Mike Galbraith
2015-07-06 5:13 ` Mike Galbraith
2015-07-06 14:34 ` Josef Bacik
2015-07-06 18:36 ` Mike Galbraith
2015-07-06 19:41 ` Josef Bacik
2015-07-07 4:01 ` Mike Galbraith
2015-07-07 9:43 ` [patch] " Mike Galbraith
2015-07-07 13:40 ` Josef Bacik
2015-07-07 15:24 ` Mike Galbraith
2015-07-07 17:06 ` Josef Bacik
2015-07-08 6:13 ` [patch] sched: beef up wake_wide() Mike Galbraith
2015-07-09 13:26 ` Peter Zijlstra
2015-07-09 14:07 ` Mike Galbraith
2015-07-09 14:46 ` Mike Galbraith
2015-07-10 5:19 ` Mike Galbraith
2015-07-10 13:41 ` Josef Bacik
2015-07-10 20:59 ` Josef Bacik
2015-07-11 3:11 ` Mike Galbraith
2015-07-13 13:53 ` Josef Bacik
2015-07-14 11:19 ` Peter Zijlstra
2015-07-14 13:49 ` Mike Galbraith
2015-07-14 14:07 ` Peter Zijlstra
2015-07-14 14:17 ` Mike Galbraith
2015-07-14 15:04 ` Peter Zijlstra
2015-07-14 15:39 ` Mike Galbraith
2015-07-14 16:01 ` Josef Bacik
2015-07-14 17:59 ` Mike Galbraith
2015-07-15 17:11 ` Josef Bacik
2015-08-03 17:07 ` [tip:sched/core] sched/fair: Beef " tip-bot for Mike Galbraith
2015-05-28 11:16 ` [PATCH RESEND] sched: prefer an idle cpu vs an idle sibling for BALANCE_WAKE Mike Galbraith
2015-05-28 11:49 ` Ingo Molnar
2015-05-28 12:15 ` Mike Galbraith
2015-05-28 12:19 ` Peter Zijlstra
2015-05-28 12:29 ` Ingo Molnar
2015-05-28 15:22 ` David Ahern
2015-05-28 11:55 ` Srikar Dronamraju
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