Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030361AbWAXIID (ORCPT ); Tue, 24 Jan 2006 03:08:03 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030366AbWAXIID (ORCPT ); Tue, 24 Jan 2006 03:08:03 -0500 Received: from mustang.oldcity.dca.net ([216.158.38.3]:13547 "HELO mustang.oldcity.dca.net") by vger.kernel.org with SMTP id S1030364AbWAXIIA (ORCPT ); Tue, 24 Jan 2006 03:08:00 -0500 Subject: Re: RCU latency regression in 2.6.16-rc1 From: Lee Revell To: Ingo Molnar Cc: linux-kernel , Linus Torvalds , "Paul E. McKenney" In-Reply-To: <20060124080157.GA25855@elte.hu> References: <1138089139.2771.78.camel@mindpipe> <20060124075640.GA24806@elte.hu> <1138089483.2771.81.camel@mindpipe> <20060124080157.GA25855@elte.hu> Content-Type: text/plain Date: Tue, 24 Jan 2006 03:07:58 -0500 Message-Id: <1138090078.2771.88.camel@mindpipe> Mime-Version: 1.0 X-Mailer: Evolution 2.5.4 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1000 Lines: 29 On Tue, 2006-01-24 at 09:01 +0100, Ingo Molnar wrote: > * Lee Revell wrote: > > > On Tue, 2006-01-24 at 08:56 +0100, Ingo Molnar wrote: > > > * Lee Revell wrote: > > > > > > > I ported the latency tracer to 2.6.16 and got this 13ms latency within > > > > a few hours. This is a regression from 2.6.15. > > > > > > > > It appears that RCU can invoke ipv4_dst_destroy thousands of times in > > > > a single batch. > > > > > > could you try the PREEMPT_RCU patch below? > > > > Sure. If it works do you see this making it in 2.6.16? Otherwise we > > still would have a regression... > > nope, that likely wont make v2.6.16, which is frozen already. > How about just lowering maxbatch to 1000? Lee - 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/