From: Peter Zijlstra <peterz@infradead.org>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Yuyang Du <yuyang.du@intel.com>, Ingo Molnar <mingo@kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Benjamin Segall <bsegall@google.com>,
Paul Turner <pjt@google.com>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Matt Fleming <matt@codeblueprint.co.uk>,
Mike Galbraith <umgwanakikbuti@gmail.com>
Subject: Re: [PATCH v1 00/10] Optimize sched avgs computation and implement flat util hierarchy
Date: Tue, 23 Aug 2016 16:13:41 +0200 [thread overview]
Message-ID: <20160823141341.GP10153@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <CAKfTPtAMWbx6m2X8k_px+TK7OGAqgzD+0ShwfNb02xP1O8wg0Q@mail.gmail.com>
On Tue, Aug 23, 2016 at 03:28:19PM +0200, Vincent Guittot wrote:
> I still wonder if using a flat util hierarchy is the right solution to
> solve this problem with utilization and task group. I have noticed
> exact same issues with load that generates weird task placement
> decision and i think that we should probably try to solve both wrong
> behavior with same mechanism. but this is not possible with flat
> hierarchy for load
>
> Let me take an example.
> TA is a always running task on CPU1 in group /root/level1/
> TB wakes up on CPU0 and moves TA into group /root/level2/
> Even if TA stays on CPU1, runnable_load_avg of CPU1 root cfs rq will become 0.
Because while we migrate the load_avg on /root/level2, we do not
propagate the load_avg up the hierarchy?
And always propagating everyrthing up will indeed also fix the
utilization issue.
Of course, doing that propagation has its costs..
Didn't you post a patch doing just this a while ago?
next prev parent reply other threads:[~2016-08-23 14:13 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-10 0:14 [PATCH v1 00/10] Optimize sched avgs computation and implement flat util hierarchy Yuyang Du
2016-08-10 0:14 ` [PATCH v1 01/10] sched/fair: Chance LOAD_AVG_MAX_N from 345 to 347 Yuyang Du
2016-08-24 16:01 ` Vincent Guittot
2016-08-29 0:07 ` Yuyang Du
2016-08-10 0:14 ` [PATCH v1 02/10] documentation: Add scheduler/sched-avg.txt Yuyang Du
2016-08-22 16:48 ` Randy Dunlap
2016-08-10 0:14 ` [PATCH v1 03/10] sched/fair: Add static to remove_entity_load_avg() Yuyang Du
2016-08-10 0:14 ` [PATCH v1 04/10] sched/fair: Rename variable names for sched averages Yuyang Du
2016-08-10 0:14 ` [PATCH v1 05/10] sched/fair: Add __always_inline compiler attribute to __accumulate_sum() Yuyang Du
2016-08-10 0:14 ` [PATCH v1 06/10] sched/fair: Optimize __update_sched_avg() Yuyang Du
2016-08-10 0:14 ` [PATCH v1 07/10] sched/fair: Remove useless 64-bit to 32-bit variable conversion Yuyang Du
2016-08-25 7:11 ` Vincent Guittot
2016-08-29 1:00 ` Yuyang Du
2016-08-10 0:14 ` [PATCH v1 08/10] sched/fair: Remove scale_load_down() for load_avg Yuyang Du
2016-08-10 0:14 ` [PATCH v1 09/10] sched/fair: Rename scale_load() and scale_load_down() Yuyang Du
2016-08-10 0:14 ` [PATCH v1 10/10] sched/fair: Implement flat hierarchical structure for util_avg Yuyang Du
2016-08-10 0:23 ` [PATCH v1 00/10] Optimize sched avgs computation and implement flat util hierarchy Yuyang Du
2016-08-22 23:26 ` Yuyang Du
2016-08-23 13:28 ` Vincent Guittot
2016-08-23 14:13 ` Peter Zijlstra [this message]
2016-08-23 14:45 ` Vincent Guittot
2016-08-23 15:39 ` Dietmar Eggemann
2016-08-29 1:37 ` Yuyang Du
2016-09-01 18:32 ` Dietmar Eggemann
2016-08-24 8:54 ` Morten Rasmussen
2016-08-24 9:48 ` Vincent Guittot
2016-08-29 19:00 ` Yuyang Du
2016-09-01 14:22 ` Morten Rasmussen
2016-08-23 19:09 ` Yuyang Du
2016-08-23 19:01 ` Yuyang Du
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=20160823141341.GP10153@twins.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=bsegall@google.com \
--cc=dietmar.eggemann@arm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=matt@codeblueprint.co.uk \
--cc=mingo@kernel.org \
--cc=morten.rasmussen@arm.com \
--cc=pjt@google.com \
--cc=umgwanakikbuti@gmail.com \
--cc=vincent.guittot@linaro.org \
--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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox