From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Subject: Re: -27% netperf TCP_STREAM regression by "tcp_memcontrol: Kill struct tcp_memcontrol" Date: Tue, 22 Oct 2013 21:38:10 -0700 Message-ID: <87k3h461ql.fsf@tw-ebiederman.twitter.com> References: <20131022214129.GB2715@localhost> <20131022.180023.1141845387743361648.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain Cc: fengguang.wu@intel.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: David Miller Return-path: In-Reply-To: <20131022.180023.1141845387743361648.davem@davemloft.net> (David Miller's message of "Tue, 22 Oct 2013 18:00:23 -0400 (EDT)") Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 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