From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: Strange CPU load when flushing route cache (kernel 2.6.31.6) Date: Mon, 23 Nov 2009 14:25:21 +0100 Message-ID: <4B0A8D41.6010608@gmail.com> References: <1258970332.29747.262.camel@jdb-workstation> <4B0A63FA.5000804@gmail.com> <1258979320.29747.270.camel@jdb-workstation> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Linux Kernel Network Hackers , Robert Olsson To: Jesper Dangaard Brouer Return-path: Received: from gw1.cosmosbay.com ([212.99.114.194]:46801 "EHLO gw1.cosmosbay.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751358AbZKWNZR (ORCPT ); Mon, 23 Nov 2009 08:25:17 -0500 In-Reply-To: <1258979320.29747.270.camel@jdb-workstation> Sender: netdev-owner@vger.kernel.org List-ID: Jesper Dangaard Brouer a =C3=A9crit : > On Mon, 2009-11-23 at 11:29 +0100, Eric Dumazet wrote: >> Sure, after a flush, we have to rebuild the cache, so extra work is = expected. >=20 > But the old 2.6.25.7 do NOT show this behavior... That is the real > issue... Previous kernels were crashing, because flush was immediate and not def= erred as today. During flush, we were dropping enormous amounts of packets. Now, its possible to have setups with equilibrium and no packet loss, because we smoothtly invalidate cache entries. > I did the cache flushing due to some historical issues, that I think = you > did a fix for... Guess I can drop the flushing and see if the garbage > collection can keep up... Yes it can. Unless your route cache settings are not optimal. >=20 >> Do you run a 2G/2G User/Kernel split kernel ? >=20 > Not sure, how do I check? grep LowTotal /proc/meminfo or dmesg | grep LOWMEM 913MB LOWMEM available. (standard 3G/1G User/Kernel split)