From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============5385074225356530698==" MIME-Version: 1.0 From: Mel Gorman To: lkp@lists.01.org Subject: Re: [mm] 795ae7a0de: pixz.throughput -9.1% regression Date: Fri, 03 Jun 2016 10:00:46 +0100 Message-ID: <20160603090046.GF2469@suse.de> In-Reply-To: <20160602160706.GA24004@cmpxchg.org> List-Id: --===============5385074225356530698== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable On Thu, Jun 02, 2016 at 12:07:06PM -0400, Johannes Weiner wrote: > right before the test is running? I wonder if it's mostly filled with > cache, and the increase in watermarks causes a higher portion of the > anon allocs and frees to spill to the remote node, but never enough to > enter the allocator slowpath and waking kswapd to fix it. > = > Another suspect is the fair zone allocator, whose allocation batches > increased as well. It shouldn't affect NUMA placement, but I wonder if > there is a bug in there that causes false spilling to foreign nodes > that was only bounded by the allocation batch of the foreign zone. > Mel, does such a symptom sound familiar in any way? > = Unfortunately not. The closest I've seen recently is bugs in the page allocator patches that artifically enters the slow path prematurely but that does not appear to apply here. -- = Mel Gorman SUSE Labs --===============5385074225356530698==-- From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932349AbcFCJA6 (ORCPT ); Fri, 3 Jun 2016 05:00:58 -0400 Received: from mx2.suse.de ([195.135.220.15]:49856 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932318AbcFCJA4 (ORCPT ); Fri, 3 Jun 2016 05:00:56 -0400 Date: Fri, 3 Jun 2016 10:00:46 +0100 From: Mel Gorman To: Johannes Weiner Cc: kernel test robot , Linus Torvalds , Rik van Riel , David Rientjes , Joonsoo Kim , Andrew Morton , LKML , lkp@01.org Subject: Re: [lkp] [mm] 795ae7a0de: pixz.throughput -9.1% regression Message-ID: <20160603090046.GF2469@suse.de> References: <574fd097.Frf8OIpckXVh1oaw%xiaolong.ye@intel.com> <20160602064507.GE30850@yexl-desktop> <20160602160706.GA24004@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20160602160706.GA24004@cmpxchg.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 02, 2016 at 12:07:06PM -0400, Johannes Weiner wrote: > right before the test is running? I wonder if it's mostly filled with > cache, and the increase in watermarks causes a higher portion of the > anon allocs and frees to spill to the remote node, but never enough to > enter the allocator slowpath and waking kswapd to fix it. > > Another suspect is the fair zone allocator, whose allocation batches > increased as well. It shouldn't affect NUMA placement, but I wonder if > there is a bug in there that causes false spilling to foreign nodes > that was only bounded by the allocation batch of the foreign zone. > Mel, does such a symptom sound familiar in any way? > Unfortunately not. The closest I've seen recently is bugs in the page allocator patches that artifically enters the slow path prematurely but that does not appear to apply here. -- Mel Gorman SUSE Labs