From: Dietmar Eggemann <dietmar.eggemann@arm.com>
To: Mike Galbraith <umgwanakikbuti@gmail.com>,
Peter Zijlstra <peterz@infradead.org>
Cc: Yuyang Du <yuyang.du@intel.com>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [rfc patch] sched/fair: Use instantaneous load for fork/exec balancing
Date: Wed, 15 Jun 2016 20:03:19 +0100 [thread overview]
Message-ID: <5761A677.3060609@arm.com> (raw)
In-Reply-To: <1466006609.4219.40.camel@gmail.com>
On 15/06/16 17:03, Mike Galbraith wrote:
> On Wed, 2016-06-15 at 16:32 +0100, Dietmar Eggemann wrote:
>
>>> In general, the fuzz helps us to not be so spastic. I'm not sure that
>>> we really really need to care all that much, because I strongly suspect
>>> that it's only gonna make any difference at all in corner cases, but
>>> there are real world cases that matter. I know for fact that schbench
>>> (facebook) which is at least based on a real world load fails early due
>>> to us stacking tasks due to that fuzzy view of reality. In that case,
>>> it's because the fuzz consists of a high amplitude aging sawtooth..
>>
>> ... only for fork/exec?
>
> No. Identical workers had longish work/sleep cycle, aging resulted in
> weights that ranged from roughly 300-700(ish), depending on when you
> peeked at them.
>
> -Mike
>
Isn't there a theoretical problem with the scale_load() on CONFIG_64BIT
machines on tip/sched/core? load.weight has a higher resolution than
runnable_load_avg (and so the values in the rq->cpu_load[] array).
Theoretically because [forkexec|wake]_idx is 0 so [target|source]_load()
is nothing else than weighted_cpuload().
next prev parent reply other threads:[~2016-06-15 19:03 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-14 7:58 [rfc patch] sched/fair: Use instantaneous load for fork/exec balancing Mike Galbraith
2016-06-14 14:14 ` Dietmar Eggemann
2016-06-14 16:40 ` Mike Galbraith
2016-06-15 15:32 ` Dietmar Eggemann
2016-06-15 16:03 ` Mike Galbraith
2016-06-15 19:03 ` Dietmar Eggemann [this message]
2016-06-16 3:33 ` Mike Galbraith
2016-06-16 9:01 ` Dietmar Eggemann
2016-07-04 15:04 ` Matt Fleming
2016-07-04 17:43 ` Mike Galbraith
2016-07-06 11:45 ` Matt Fleming
2016-07-06 12:21 ` Mike Galbraith
2016-07-11 8:58 ` Dietmar Eggemann
2016-07-12 11:14 ` Matt Fleming
2016-06-14 22:42 ` Yuyang Du
2016-06-15 7:01 ` Mike Galbraith
2016-06-16 11:46 ` [patch] sched/fair: Use instantaneous load in wakeup paths Mike Galbraith
2016-06-16 12:04 ` Mike Galbraith
2016-06-16 12:41 ` Mike Galbraith
2016-06-17 6:21 ` Mike Galbraith
2016-06-17 10:55 ` Dietmar Eggemann
2016-06-17 13:57 ` Mike Galbraith
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5761A677.3060609@arm.com \
--to=dietmar.eggemann@arm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=peterz@infradead.org \
--cc=umgwanakikbuti@gmail.com \
--cc=yuyang.du@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.