From: Mike Galbraith <efault@gmx.de>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Paul Turner <pjt@google.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Arnaldo Carvalho de Melo <acme@infradead.org>,
Clark Williams <clark@redhat.com>,
Andrew Theurer <habanero@us.ibm.com>
Subject: Re: [RFC] sched: The removal of idle_balance()
Date: Sun, 17 Feb 2013 08:14:05 +0100 [thread overview]
Message-ID: <1361085245.28353.3.camel@marge.simpson.net> (raw)
In-Reply-To: <1361082363.6088.21.camel@marge.simpson.net>
On Sun, 2013-02-17 at 07:26 +0100, Mike Galbraith wrote:
> On Sat, 2013-02-16 at 11:12 -0500, Steven Rostedt wrote:
> > On Fri, 2013-02-15 at 08:26 +0100, Mike Galbraith wrote:
> > > On Fri, 2013-02-15 at 01:13 -0500, Steven Rostedt wrote:
> > >
> > > > Think about it some more, just because we go idle isn't enough reason to
> > > > pull a runable task over. CPUs go idle all the time, and tasks are woken
> > > > up all the time. There's no reason that we can't just wait for the sched
> > > > tick to decide its time to do a bit of balancing. Sure, it would be nice
> > > > if the idle CPU did the work. But I think that frame of mind was an
> > > > incorrect notion from back in the early 2000s and does not apply to
> > > > today's hardware, or perhaps it doesn't apply to the (relatively) new
> > > > CFS scheduler. If you want aggressive scheduling, make the task rt, and
> > > > it will do aggressive scheduling.
> > >
> > > (the throttle is supposed to keep idle_balance() from doing severe
> > > damage, that may want a peek/tweak)
> > >
> > > Hackbench spreads itself with FORK/EXEC balancing, how does say a kbuild
> > > do with no idle_balance()?
> > >
> >
> > Interesting, I added this patch and it brought down my hackbench to the
> > same level as removing idle_balance().
>
> The typo did it's job well :)
>
> Hrm, turning idle balancing off here does not help hackbench at all.
(And puts a dent in x264 ultrafast)
+SD_BALANCE_NEWIDLE
encoded 600 frames, 425.04 fps, 22132.71 kb/s
encoded 600 frames, 416.07 fps, 22132.71 kb/s
encoded 600 frames, 417.49 fps, 22132.71 kb/s
encoded 600 frames, 420.65 fps, 22132.71 kb/s
encoded 600 frames, 425.55 fps, 22132.71 kb/s
encoded 600 frames, 425.58 fps, 22132.71 kb/s
encoded 600 frames, 426.18 fps, 22132.71 kb/s
encoded 600 frames, 424.21 fps, 22132.71 kb/s
encoded 600 frames, 422.20 fps, 22132.71 kb/s
encoded 600 frames, 423.15 fps, 22132.71 kb/s
-SD_BALANCE_NEWIDLE
encoded 600 frames, 378.52 fps, 22132.71 kb/s
encoded 600 frames, 378.75 fps, 22132.71 kb/s
encoded 600 frames, 378.20 fps, 22132.71 kb/s
encoded 600 frames, 372.54 fps, 22132.71 kb/s
encoded 600 frames, 366.69 fps, 22132.71 kb/s
encoded 600 frames, 378.46 fps, 22132.71 kb/s
encoded 600 frames, 379.89 fps, 22132.71 kb/s
encoded 600 frames, 382.25 fps, 22132.71 kb/s
encoded 600 frames, 384.10 fps, 22132.71 kb/s
encoded 600 frames, 375.24 fps, 22132.71 kb/s
next prev parent reply other threads:[~2013-02-17 7:14 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-15 6:13 [RFC] sched: The removal of idle_balance() Steven Rostedt
2013-02-15 7:26 ` Mike Galbraith
2013-02-15 12:07 ` Peter Zijlstra
2013-02-15 12:21 ` Peter Zijlstra
2013-02-15 12:32 ` Mike Galbraith
2013-02-16 16:12 ` Steven Rostedt
2013-02-17 6:26 ` Mike Galbraith
2013-02-17 7:14 ` Mike Galbraith [this message]
2013-02-17 21:54 ` Steven Rostedt
2013-02-18 3:42 ` Mike Galbraith
2013-02-18 15:23 ` Steven Rostedt
2013-02-18 17:22 ` Mike Galbraith
2013-02-15 7:45 ` Joonsoo Kim
2013-02-15 15:05 ` Steven Rostedt
2013-02-17 6:26 ` Mike Galbraith
2013-02-18 8:13 ` Srikar Dronamraju
2013-02-18 15:25 ` Steven Rostedt
2013-02-19 4:13 ` Rakib Mullick
2013-02-19 7:29 ` Michael Wang
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=1361085245.28353.3.camel@marge.simpson.net \
--to=efault@gmx.de \
--cc=acme@infradead.org \
--cc=akpm@linux-foundation.org \
--cc=clark@redhat.com \
--cc=fweisbec@gmail.com \
--cc=habanero@us.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=pjt@google.com \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
/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;
as well as URLs for NNTP newsgroup(s).