Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S270283AbTGRTXn (ORCPT ); Fri, 18 Jul 2003 15:23:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S270295AbTGRTXn (ORCPT ); Fri, 18 Jul 2003 15:23:43 -0400 Received: from x35.xmailserver.org ([208.129.208.51]:32985 "EHLO x35.xmailserver.org") by vger.kernel.org with ESMTP id S270283AbTGRTXl (ORCPT ); Fri, 18 Jul 2003 15:23:41 -0400 X-AuthUser: davidel@xmailserver.org Date: Fri, 18 Jul 2003 12:31:21 -0700 (PDT) From: Davide Libenzi X-X-Sender: davide@bigblue.dev.mcafeelabs.com To: Valdis.Kletnieks@vt.edu cc: linux kernel mailing list Subject: Re: [PATCH] O6int for interactivity In-Reply-To: <200307181739.h6IHdFq3006996@turing-police.cc.vt.edu> Message-ID: References: <5.2.1.1.2.20030718120229.01a8fcf0@pop.gmx.net> <5.2.1.1.2.20030718071656.01af84d0@pop.gmx.net> <200307170030.25934.kernel@kolivas.org> <200307170030.25934.kernel@kolivas.org> <5.2.1.1.2.20030718071656.01af84d0@pop.gmx.net> <5.2.1.1.2.20030718120229.01a8fcf0@pop.gmx.net> <5.2.1.1.2.20030718174433.01b12878@pop.gmx.net> <200307181739.h6IHdFq3006996@turing-police.cc.vt.edu> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1440 Lines: 34 On Fri, 18 Jul 2003 Valdis.Kletnieks@vt.edu wrote: > On Fri, 18 Jul 2003 10:05:05 PDT, Davide Libenzi said: > > On Fri, 18 Jul 2003, Davide Libenzi wrote: > > > > > control them. It is right to apply uncontrolled unfairness to userspace > > > tasks though. > > > > s/It is right/It is not right/ > > OK.. but is it right to apply *controlled* unfairness to userspace? I'm sorry to say that guys, but I'm afraid it's what we have to do. We did not think about it when this scheduler was dropped inside 2.5 sadly. The interactivity concept is based on the fact that a particular class of tasks characterized by certain sleep->burn patterns are never expired and eventually, only oscillate between two (pretty high) priorities. Without applying a global CPU throttle for interactive tasks, you can create a small set of processes (like irman does) that hit the coded sleep->burn pattern and that make everything is running with priority lower than the lower of the two of the oscillation range, to almost completely starve. Controlled unfairness would mean throttling the CPU time we reserve to interactive tasks so that we always reserve a minimum time to non interactive processes. - Davide - 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/