Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263843AbUDFTzv (ORCPT ); Tue, 6 Apr 2004 15:55:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263980AbUDFTzv (ORCPT ); Tue, 6 Apr 2004 15:55:51 -0400 Received: from e6.ny.us.ibm.com ([32.97.182.106]:58038 "EHLO e6.ny.us.ibm.com") by vger.kernel.org with ESMTP id S263843AbUDFTzu (ORCPT ); Tue, 6 Apr 2004 15:55:50 -0400 Date: Wed, 7 Apr 2004 01:22:49 +0530 From: Dipankar Sarma To: Robert Olsson Cc: Andrea Arcangeli , "David S. Miller" , kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@oss.sgi.com, paulmck@us.ibm.com, akpm@osdl.org Subject: Re: route cache DoS testing and softirqs Message-ID: <20040406195249.GA4581@in.ibm.com> Reply-To: dipankar@in.ibm.com References: <20040330133000.098761e2.davem@redhat.com> <20040330213742.GL3808@dualathlon.random> <20040331171023.GA4543@in.ibm.com> <16491.4593.718724.277551@robur.slu.se> <20040331203750.GB4543@in.ibm.com> <20040331212817.GQ2143@dualathlon.random> <20040331214342.GD4543@in.ibm.com> <16497.37720.607342.193544@robur.slu.se> <20040405212220.GH4003@in.ibm.com> <16498.43191.733850.18276@robur.slu.se> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <16498.43191.733850.18276@robur.slu.se> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1380 Lines: 30 On Tue, Apr 06, 2004 at 02:55:19PM +0200, Robert Olsson wrote: Content-Description: message body text > Dipankar Sarma writes: > > Looks better atleast. Can you apply the following patch (rs-throttle-rcu) > > on top of rcu-softirq.patch in your tree and see if helps a little bit more ? > > Please make sure to set the kernel paramenters rcupdate.maxbatch to 4 > > and rcupdate.plugticks to 0. You can make sure of those parameters > > by looking at dmesg (rcu prints them out during boot). I just merged > > it, but have not tested this patch yet. > > OK! > > Well not tested yet but I don't think we will get rid overflow totally in my > setup. I've done a little experimental patch so *all* softirq's are run via > ksoftirqd. Robert, you should try out rs-throttle-rcu.patch. The idea is that we don't run too many callbacks in a single rcu. In my setup, at 100kpps, I see as many as 30000 rcu callbacks in a single tasklet handler. That is likely hurting even the softirq-only RCU grace periods. Setting rcupdate.maxbatch=4 will do only 4 per tasklet thus providing more quiescent points to the system. 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/