Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262894AbUC2MbT (ORCPT ); Mon, 29 Mar 2004 07:31:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262910AbUC2MaR (ORCPT ); Mon, 29 Mar 2004 07:30:17 -0500 Received: from e1.ny.us.ibm.com ([32.97.182.101]:25281 "EHLO e1.ny.us.ibm.com") by vger.kernel.org with ESMTP id S262894AbUC2MVr (ORCPT ); Mon, 29 Mar 2004 07:21:47 -0500 Date: Mon, 29 Mar 2004 17:50:45 +0530 From: Dipankar Sarma To: Takashi Iwai Cc: "Paul E. McKenney" , Arjan van de Ven , Robert Love , Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: [PATCH] RCU for low latency (experimental) Message-ID: <20040329122045.GB3683@in.ibm.com> Reply-To: dipankar@in.ibm.com References: <20040324175142.GW2065@dualathlon.random> <20040324213914.GD4539@in.ibm.com> <20040324225326.GH2065@dualathlon.random> <20040324231145.GB12035@in.ibm.com> <20040324233430.GJ2065@dualathlon.random> <20040324234643.GD12035@in.ibm.com> <20040328172036.GH5648@in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1128 Lines: 28 On Mon, Mar 29, 2004 at 12:43:11PM +0200, Takashi Iwai wrote: > At Sun, 28 Mar 2004 19:28:41 +0200, > I wrote: > > > > > > anyway, i confirmed that with the original krcud patch the latency > > > > with dcache flood can be eliminated. > > > > > > Does the throttle-rcu patch also help eliminate dcache flood ? You > > > can try by just changing count >= rcumaxbatch to ++count > rcumaxbatch. > > > > i'll try it later. > > the throttle-rcu patch does work indeed well even without preemption. > i've tested maxbatch=16 and plugticks=0. in the older version, there > was 20ms long latency, while in the patched version, no measurable > latency more than 1ms. Thanks for the measurements. throttle-rcu may eventually be the way to go, but I would wait until we have sorted out several other problems like route cache DoS testing that we are looking at currently. Thanks Dipankar - 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/