Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755180Ab0LEU7K (ORCPT ); Sun, 5 Dec 2010 15:59:10 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:44658 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753896Ab0LEU7I (ORCPT ); Sun, 5 Dec 2010 15:59:08 -0500 Date: Sun, 5 Dec 2010 21:58:44 +0100 From: Ingo Molnar To: Con Kolivas Cc: Colin Walters , Linus Torvalds , Mike Galbraith , Oleg Nesterov , Peter Zijlstra , Markus Trippelsdorf , Mathieu Desnoyers , linux-kernel@vger.kernel.org Subject: Re: [PATCH v4] sched: automated per session task groups Message-ID: <20101205205844.GA7902@elte.hu> References: <1289783580.495.58.camel@maggy.simson.net> <201012052118.43843.kernel@kolivas.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201012052118.43843.kernel@kolivas.org> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1617 Lines: 49 * Con Kolivas wrote: > Greets. > > I applaud your efforts to continue addressing interactivity and responsiveness > but, I know I'm going to regret this, I feel strongly enough to speak up about > this change. > > On Sun, 5 Dec 2010 10:43:44 Colin Walters wrote: > > On Sat, Dec 4, 2010 at 5:39 PM, Linus Torvalds > > wrote: > > > What's your point again? It's a heuristic. > > > > So if it's a heuristic the OS can get wrong, > > This is precisely what I see as the flaw in this approach. [...] I think you are misunderstanding Mike's auto-group scheduling feature. The scheduling itself is not 'heuristics'. It is the _composition of a group_ that has a heuristic default. (We use the 'tty' to act as the grouping) But that can be changed: the cgroup interfaces can be (and are) used by Gnome to create different groups. They can be used by users as well, using cgroup tooling. What the kernel does is that it provides sane defaults. > [...] > > Move away from the fragile heuristic tweaks and find a longer term robust > solution. This is not some kernel heuristic that cannot be modified - which was the main problem of the O(1) scheduler. This is a common-sense default that can be overriden by user-space if it wants to. So i definitely think you are confusing the two cases. Thanks, Ingo -- 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/