From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266670AbUGKXL2 (ORCPT ); Sun, 11 Jul 2004 19:11:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266671AbUGKXL2 (ORCPT ); Sun, 11 Jul 2004 19:11:28 -0400 Received: from peabody.ximian.com ([130.57.169.10]:34720 "EHLO peabody.ximian.com") by vger.kernel.org with ESMTP id S266670AbUGKXLL (ORCPT ); Sun, 11 Jul 2004 19:11:11 -0400 Subject: Re: [announce] [patch] Voluntary Kernel Preemption Patch From: Robert Love To: Ingo Molnar Cc: Andrew Morton , linux-kernel@vger.kernel.org, arjanv@redhat.com, linux-audio-dev@music.columbia.edu In-Reply-To: <20040711103020.GA24797@elte.hu> References: <20040709182638.GA11310@elte.hu> <20040710222510.0593f4a4.akpm@osdl.org> <20040711093209.GA17095@elte.hu> <20040711024518.7fd508e0.akpm@osdl.org> <20040711095039.GA22391@elte.hu> <20040711025855.08afbca1.akpm@osdl.org> <20040711103020.GA24797@elte.hu> Content-Type: text/plain Date: Sun, 11 Jul 2004 19:12:23 -0400 Message-Id: <1089587543.3619.9.camel@lucy> Mime-Version: 1.0 X-Mailer: Evolution 1.5.8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2004-07-11 at 12:30 +0200, Ingo Molnar wrote: > the reason is difference in overhead (codesize, speed) and risks (driver > robustness). We do not want to enable preempt for Fedora yet because it > breaks just too much stuff and is too heavy. So we looked for a solution > that might work for a generic distro. I think we should work toward being able to enable kernel preemption in Fedora, then, instead of other tangential solutions. And I disagree with the overhead argument. I have seen no specific arguments that show a significant overhead. Heck, when people tried to show that kernel preemption hurt throughput, we saw tests that showed improved throughput (probably due to better utilization of I/O). But stability is a subjective argument (and I agree we need more driver love, at least for obscure drivers) wrt kernel preemption. So I would say we should concentrate on working on the stability[1] so we could just enable kernel preemption unconditionally and not designing new solutions. Best, Robert Love [1] What better way than enabling CONFIG_PREEMPT for Fedora? Enable it for Fedora, and do not enable it for Red Hat Enterprise until you are confidant. ;-)