Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758872Ab1EMJqh (ORCPT ); Fri, 13 May 2011 05:46:37 -0400 Received: from casper.infradead.org ([85.118.1.10]:51947 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758162Ab1EMJqg convert rfc822-to-8bit (ORCPT ); Fri, 13 May 2011 05:46:36 -0400 Subject: Re: Sched_autogroup and niced processes From: Peter Zijlstra To: Ingo Molnar Cc: Mike Galbraith , Yong Zhang , Carl-Johan Kjellander , linux-kernel@vger.kernel.org In-Reply-To: <20110513092933.GL13647@elte.hu> References: <1305273950.15080.7.camel@marge.simson.net> <20110513082250.GB13647@elte.hu> <1305276066.2561.1.camel@twins> <20110513090537.GH13647@elte.hu> <1305277666.2561.9.camel@twins> <20110513092933.GL13647@elte.hu> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Fri, 13 May 2011 11:46:30 +0200 Message-ID: <1305279990.2466.4.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1652 Lines: 40 On Fri, 2011-05-13 at 11:29 +0200, Ingo Molnar wrote: > * Peter Zijlstra wrote: > > > On Fri, 2011-05-13 at 11:05 +0200, Ingo Molnar wrote: > > > Could we somehow automate this: > > > > > > > echo 19 > /proc/'pid of seti@home'/autogroup > > > > > > and split off nice 19 tasks into separate groups and lower the group's > > > priority? > > > > Well I guess you can stack on all kinds of heuristics, do we want to? > > Well have you seen my non-heuristic suggestion: > > | Another thing we could do is to lower the priority of a cgroup if it *only* > | runs reniced tasks. I.e. track the 'maximum priority' of cgroups and > | propagate that to their weight. > | > | This way renicing within cgroups will be more powerful and people do not have > | to muck with cgroup details. > > A cgroup assuming the highest priority of all tasks it contains is a pretty > natural definition and extension of priorities and also solves this usecase. Well, that a heuristic in my book, and it totally destroys the independence of groups from tasks (resulting in O(n) task nice behaviour). I really don't see why we should do this, if people don't want what it does, don't use it. If you want something else, you can do all these things from userspace to suit your exact needs. We have enough knobs to set things up as you want them, no need to make things more complicated. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/