From: Jiri Olsa <jolsa@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>, Ingo Molnar <mingo@kernel.org>,
James Hartsock <hartsjc@redhat.com>,
Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>,
Kirill Tkhai <ktkhai@parallels.com>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC] sched: unused cpu in affine workload
Date: Tue, 5 Apr 2016 10:56:07 +0200 [thread overview]
Message-ID: <20160405085607.GE17232@krava.brq.redhat.com> (raw)
In-Reply-To: <20160404213450.GE3448@twins.programming.kicks-ass.net>
On Mon, Apr 04, 2016 at 11:34:50PM +0200, Peter Zijlstra wrote:
> On Mon, Apr 04, 2016 at 03:45:16PM -0400, Rik van Riel wrote:
> > An optimal solution is NP hard.
> >
> > Heuristics that "move tasks with pressure" may be
> > much more doable, and lead to perfectly satisfactory
> > results, especially if most migrations happen within
> > a socket (and the same shared L3 cache).
>
> Right; trick will be finding something that mostly works without making
> the regular balance paths increase in complexity.
>
> As per the argument in kernel/sched/fair.c:5694 the current
> load-balancing averages out to O(n), and I would very much like to keep
> it that way.
guys, thanks a lot for all the thoughts and suggestions,
I'll try to come up with something
jirka
prev parent reply other threads:[~2016-04-05 8:56 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-04 8:23 Jiri Olsa
2016-04-04 8:44 ` Peter Zijlstra
2016-04-04 8:59 ` Ingo Molnar
2016-04-04 9:19 ` Ingo Molnar
2016-04-04 9:38 ` Ingo Molnar
2016-04-04 13:23 ` Peter Zijlstra
2016-04-04 19:45 ` Rik van Riel
2016-04-04 21:34 ` Peter Zijlstra
2016-04-05 8:56 ` Jiri Olsa [this message]
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