From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264501AbUG3Duu (ORCPT ); Thu, 29 Jul 2004 23:50:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264911AbUG3Duu (ORCPT ); Thu, 29 Jul 2004 23:50:50 -0400 Received: from viper.oldcity.dca.net ([216.158.38.4]:60570 "HELO viper.oldcity.dca.net") by vger.kernel.org with SMTP id S264501AbUG3Dus (ORCPT ); Thu, 29 Jul 2004 23:50:48 -0400 Subject: Re: [patch] voluntary-preempt-2.6.8-rc2-J3 From: Lee Revell To: Eric St-Laurent Cc: Ingo Molnar , Andrew Morton , wli@holomorphy.com, lenar@vision.ee, linux-kernel In-Reply-To: <1091154667.12149.15.camel@orbiter> References: <20040713122805.GZ21066@holomorphy.com> <40F3F0A0.9080100@vision.ee> <20040713143947.GG21066@holomorphy.com> <1090732537.738.2.camel@mindpipe> <1090795742.719.4.camel@mindpipe> <20040726082330.GA22764@elte.hu> <1090830574.6936.96.camel@mindpipe> <20040726083537.GA24948@elte.hu> <20040726125750.5e467cfd.akpm@osdl.org> <20040726203634.GA26096@elte.hu> <1091154667.12149.15.camel@orbiter> Content-Type: text/plain Message-Id: <1091159465.782.2.camel@mindpipe> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 Date: Thu, 29 Jul 2004 23:51:06 -0400 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2004-07-29 at 22:31, Eric St-Laurent wrote: > It might be possible to eliminate the need_resched flag. Here is an > article that talk about a event-driven preemption model. > > Quoting : > > Over the long term, MontaVista is investigating whether preemption locks > can be eliminated (or at least greatly reduced in number) by protecting > all the short-duration critical regions with spinlocks that also disable > interrupts on the local CPU, and the long-duration critical regions with > mutex locks. This is a pretty old article, from 2000, describing the preemption model they implemented on 2.4. I believe the above paragraph describes the advantages of their model vs. the approach taken by the old 2.4 low latency patches. My understanding is that the preemptible 2.6 kernel already works this way. Lee