Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753409Ab3JWLrU (ORCPT ); Wed, 23 Oct 2013 07:47:20 -0400 Received: from mga11.intel.com ([192.55.52.93]:10581 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752559Ab3JWLrT (ORCPT ); Wed, 23 Oct 2013 07:47:19 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.93,554,1378882800"; d="scan'208";a="415723762" Date: Wed, 23 Oct 2013 12:46:47 +0100 From: Fengguang Wu To: "Eric W. Biederman" Cc: David Miller , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: -27% netperf TCP_STREAM regression by "tcp_memcontrol: Kill struct tcp_memcontrol" Message-ID: <20131023114647.GA30252@localhost> References: <20131022214129.GB2715@localhost> <20131022.180023.1141845387743361648.davem@davemloft.net> <87k3h461ql.fsf@tw-ebiederman.twitter.com> <20131023061019.GA15698@localhost> <87a9i0l3v1.fsf@xmission.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87a9i0l3v1.fsf@xmission.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3641 Lines: 80 On Wed, Oct 23, 2013 at 02:43:14AM -0700, Eric W. Biederman wrote: > Fengguang Wu writes: > > > On Tue, Oct 22, 2013 at 09:38:10PM -0700, Eric W. Biederman wrote: > >> David Miller writes: > >> > >> > From: fengguang.wu@intel.com > >> > Date: Tue, 22 Oct 2013 22:41:29 +0100 > >> > > >> >> We noticed big netperf throughput regressions > >> >> > >> >> a4fe34bf902b8f709c63 2e685cad57906e19add7 > >> >> ------------------------ ------------------------ > >> >> 707.40 -40.7% 419.60 lkp-nex04/micro/netperf/120s-200%-TCP_STREAM > >> >> 2775.60 -23.7% 2116.40 lkp-sb03/micro/netperf/120s-200%-TCP_STREAM > >> >> 3483.00 -27.2% 2536.00 TOTAL netperf.Throughput_Mbps > >> >> > >> >> and bisected it to > >> >> > >> >> commit 2e685cad57906e19add7189b5ff49dfb6aaa21d3 > >> >> Author: Eric W. Biederman > >> >> Date: Sat Oct 19 16:26:19 2013 -0700 > >> >> > >> >> tcp_memcontrol: Kill struct tcp_memcontrol > >> > > >> > Eric please look into this, I'd rather have a fix to apply than revert your > >> > work. > >> > >> Will do I expect some ordering changed, and that changed the cache line > >> behavior. > >> > >> If I can't find anything we can revert this one particular patch without > >> affecting anything else, but it would be nice to keep the data structure > >> smaller. > >> > >> Fengguag what would I need to do to reproduce this? > > > > Eric, attached is the kernel config. > > > > We used these commands in the test: > > > > netserver > > netperf -t TCP_STREAM -c -C -l 120 # repeat 64 times and get average Sorry it's not about repeating, but running 64 netperf in parallel. The number 64 is 2 times the number of logical CPUs. > > btw, we've got more complete change set (attached) and also noticed > > performance increase in the TCP_SENDFILE case: > > > > a4fe34bf902b8f709c63 2e685cad57906e19add7 > > ------------------------ ------------------------ > > 707.40 -40.7% 419.60 lkp-nex04/micro/netperf/120s-200%-TCP_STREAM > > 2572.20 -17.7% 2116.20 lkp-sb03/micro/netperf/120s-200%-TCP_MAERTS > > 2775.60 -23.7% 2116.40 lkp-sb03/micro/netperf/120s-200%-TCP_STREAM > > 1006.60 -54.4% 459.40 lkp-sbx04/micro/netperf/120s-200%-TCP_STREAM > > 3278.60 -25.2% 2453.80 lkp-t410/micro/netperf/120s-200%-TCP_MAERTS > > 1902.80 +21.7% 2315.00 lkp-t410/micro/netperf/120s-200%-TCP_SENDFILE > > 3345.40 -26.7% 2451.00 lkp-t410/micro/netperf/120s-200%-TCP_STREAM > > 15588.60 -20.9% 12331.40 TOTAL netperf.Throughput_Mbps > > I have a second question. Do you mount the cgroup filesystem? Do you > set memory.kmem.tcp.limit_in_bytes? No I didn't mount cgroup at all. > If you aren't setting any memory cgroup limits or creating any groups > this change should not have had any effect whatsoever. And you haven't > mentioned it so I don't expect you are enabling the memory cgroup limits > explicitly. > > If you have enabled the memory cgroups can you please describe your > configuration as that may play a significant role. > > Eric -- 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/