From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steffen Klassert Subject: Re: Big performance loss from 3.4.63 to 3.10.13 when routing ipv4 Date: Wed, 23 Oct 2013 14:04:34 +0200 Message-ID: <20131023120434.GA22316@secunet.com> References: <3244031.uQGDddGTLF@h2o.as.studentenwerk.mhn.de> <20131022.154638.1989281525248160764.davem@davemloft.net> <20131023081255.GB10148@secunet.com> <1748378.n7GIUzQXTX@h2o.as.studentenwerk.mhn.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: David Miller , hannes@stressinduktion.org, netdev@vger.kernel.org, klassert@mathematik.tu-chemnitz.de To: Wolfgang Walter Return-path: Received: from a.mx.secunet.com ([195.81.216.161]:51273 "EHLO a.mx.secunet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753386Ab3JWMEk (ORCPT ); Wed, 23 Oct 2013 08:04:40 -0400 Content-Disposition: inline In-Reply-To: <1748378.n7GIUzQXTX@h2o.as.studentenwerk.mhn.de> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Oct 23, 2013 at 01:33:14PM +0200, Wolfgang Walter wrote: > Am Mittwoch, 23. Oktober 2013, 10:12:55 schrieb Steffen Klassert: > > On Tue, Oct 22, 2013 at 03:46:38PM -0400, David Miller wrote: > > > > > > I think we should resolve this soon, even bumping it to 2048 or 4096 > > > and leaving it at that would be I think acceptable. > > > > Yes, of course. Let's use 4096 as the default for ipv4 and ipv6. > > I'll take care of it next week. > > > > I don't know what this value actually means. But on 3.4.x it is much higher. > On a machine with 512MB ram it is 32768, on a machine with 1GB ram it is > 262144 and with 16GB ram it is 4194304. > Before we removed the routing cache, the gc threshold was scaled along with the maximum routing cache size (ip_rt_max_size). With the routing cache removal, we lost the possibility to scale with ip_rt_max_size and we had to choose a static default. Maybe we can try to tweak the gc threshold again with the available memory somehow later. But to fix it now, we need to find a reasonable default value. Would a default of 4096 meet your requirements?