From: Peter Zijlstra <peterz@infradead.org>
To: Yuyang Du <yuyang.du@intel.com>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>, linux-kernel@vger.kernel.org
Subject: Re: 4.3 group scheduling regression
Date: Tue, 13 Oct 2015 10:06:48 +0200 [thread overview]
Message-ID: <20151013080648.GP3604@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20151012195516.GM11102@intel.com>
On Tue, Oct 13, 2015 at 03:55:17AM +0800, Yuyang Du wrote:
> I think maybe the real disease is the tg->load_avg is not updated in time.
> I.e., it is after migrate, the source cfs_rq does not decrease its contribution
> to the parent's tg->load_avg fast enough.
No, using the load_avg for shares calculation seems wrong; that would
mean we'd first have to ramp up the avg before you react.
You want to react quickly to actual load changes, esp. going up.
We use the avg to guess the global group load, since that's the best
compromise we have, but locally it doesn't make sense to use the avg if
we have the actual values.
next prev parent reply other threads:[~2015-10-13 8:06 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-05 21:48 CFS scheduler unfairly prefers pinned tasks paul.szabo
2015-10-06 2:45 ` Mike Galbraith
2015-10-06 10:06 ` paul.szabo
2015-10-06 12:17 ` Mike Galbraith
2015-10-06 20:44 ` paul.szabo
2015-10-07 1:28 ` Mike Galbraith
2015-10-08 8:19 ` Mike Galbraith
2015-10-08 10:54 ` paul.szabo
2015-10-08 11:19 ` Peter Zijlstra
2015-10-10 13:22 ` [patch] sched: disable task group re-weighting on the desktop Mike Galbraith
2015-10-10 14:03 ` kbuild test robot
2015-10-10 14:41 ` Mike Galbraith
2015-10-10 17:01 ` Peter Zijlstra
2015-10-10 17:13 ` Peter Zijlstra
2015-10-11 2:25 ` Mike Galbraith
2015-10-11 17:42 ` 4.3 group scheduling regression Mike Galbraith
2015-10-12 7:23 ` Peter Zijlstra
2015-10-12 7:44 ` Mike Galbraith
2015-10-12 8:04 ` Peter Zijlstra
2015-10-12 0:53 ` Yuyang Du
2015-10-12 9:12 ` Peter Zijlstra
2015-10-12 2:12 ` Yuyang Du
2015-10-12 10:23 ` Mike Galbraith
2015-10-12 19:55 ` Yuyang Du
2015-10-13 4:08 ` Mike Galbraith
2015-10-12 20:42 ` Yuyang Du
2015-10-13 8:06 ` Peter Zijlstra [this message]
2015-10-13 0:35 ` Yuyang Du
2015-10-13 8:10 ` Peter Zijlstra
2015-10-13 0:37 ` Yuyang Du
2015-10-12 11:47 ` Peter Zijlstra
2015-10-12 19:32 ` Yuyang Du
2015-10-13 8:07 ` Peter Zijlstra
2015-10-13 2:22 ` Mike Galbraith
2015-10-12 8:48 ` Mike Galbraith
2015-10-10 20:14 ` [patch] sched: disable task group re-weighting on the desktop paul.szabo
2015-10-11 2:38 ` Mike Galbraith
2015-10-11 9:25 ` paul.szabo
2015-10-11 12:49 ` Mike Galbraith
2015-10-11 19:46 ` paul.szabo
2015-10-12 1:59 ` Mike Galbraith
2015-10-08 14:25 ` CFS scheduler unfairly prefers pinned tasks Mike Galbraith
2015-10-08 21:55 ` paul.szabo
2015-10-09 1:56 ` Mike Galbraith
2015-10-09 2:40 ` Mike Galbraith
2015-10-11 9:43 ` paul.szabo
2015-10-10 3:59 ` Wanpeng Li
2015-10-10 7:58 ` Wanpeng Li
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