Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757536Ab2HQOZs (ORCPT ); Fri, 17 Aug 2012 10:25:48 -0400 Received: from mga01.intel.com ([192.55.52.88]:42397 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756930Ab2HQOZj (ORCPT ); Fri, 17 Aug 2012 10:25:39 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.77,785,1336374000"; d="scan'208";a="203555675" Date: Fri, 17 Aug 2012 22:25:26 +0800 From: Fengguang Wu To: "Theodore Ts'o" , Marti Raudsepp , Kernel hackers , ext4 hackers , maze@google.com, "Shi, Alex" , linux-fsdevel@vger.kernel.org Cc: linux RAID , NeilBrown , Li Shaohua Subject: Re: ext4 write performance regression in 3.6-rc1 on RAID0/5 Message-ID: <20120817142526.GA1059@localhost> References: <20120816024654.GB3781@thunk.org> <20120816111051.GA16036@localhost> <20120816152513.GA31346@thunk.org> <20120817060915.GB28786@localhost> <20120817134039.GB11439@thunk.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120817134039.GB11439@thunk.org> 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: 5317 Lines: 75 [CC md list] On Fri, Aug 17, 2012 at 09:40:39AM -0400, Theodore Ts'o wrote: > On Fri, Aug 17, 2012 at 02:09:15PM +0800, Fengguang Wu wrote: > > Ted, > > > > I find ext4 write performance dropped by 3.3% on average in the > > 3.6-rc1 merge window. xfs and btrfs are fine. > > > > Two machines are tested. The performance regression happens in the > > lkp-nex04 machine, which is equipped with 12 SSD drives. lkp-st02 does > > not see regression, which is equipped with HDD drives. I'll continue > > to repeat the tests and report variations. > > Hmm... I've checked out the commits in "git log v3.5..v3.6-rc1 -- > fs/ext4 fs/jbd2" and I don't see anything that I would expect would > cause that. The are the lock elimination changes for Direct I/O > overwrites, but that shouldn't matter for your tests which are > measuring buffered writes, correct? > > Is there any chance you could do me a favor and do a git bisect > restricted to commits involving fs/ext4 and fs/jbd2? I noticed that the regressions all happen in the RAID0/RAID5 cases. So it may be some interactions between the RAID/ext4 code? I'll try to get some ext2/3 numbers, which should have less changes on the fs side. wfg@bee /export/writeback% ./compare -g ext4 lkp-nex04/*/*-{3.5.0,3.6.0-rc1+} 3.5.0 3.6.0-rc1+ ------------------------ ------------------------ 720.62 -1.5% 710.16 lkp-nex04/JBOD-12HDD-thresh=1000M/ext4-100dd-1-3.5.0 706.04 -0.0% 705.86 lkp-nex04/JBOD-12HDD-thresh=1000M/ext4-10dd-1-3.5.0 702.86 -0.2% 701.74 lkp-nex04/JBOD-12HDD-thresh=1000M/ext4-1dd-1-3.5.0 702.41 -0.0% 702.06 lkp-nex04/JBOD-12HDD-thresh=1000M/ext4-1dd-2-3.5.0 779.52 +6.5% 830.11 lkp-nex04/JBOD-12HDD-thresh=100M/ext4-100dd-1-3.5.0 646.70 +4.9% 678.59 lkp-nex04/JBOD-12HDD-thresh=100M/ext4-10dd-1-3.5.0 704.49 +2.6% 723.00 lkp-nex04/JBOD-12HDD-thresh=100M/ext4-1dd-1-3.5.0 704.21 +1.2% 712.47 lkp-nex04/JBOD-12HDD-thresh=100M/ext4-1dd-2-3.5.0 705.26 -1.2% 696.61 lkp-nex04/JBOD-12HDD-thresh=8G/ext4-100dd-1-3.5.0 703.37 +0.1% 703.76 lkp-nex04/JBOD-12HDD-thresh=8G/ext4-10dd-1-3.5.0 701.66 -0.1% 700.83 lkp-nex04/JBOD-12HDD-thresh=8G/ext4-1dd-1-3.5.0 701.17 +0.0% 701.36 lkp-nex04/JBOD-12HDD-thresh=8G/ext4-1dd-2-3.5.0 675.08 -10.5% 604.29 lkp-nex04/RAID0-12HDD-thresh=1000M/ext4-100dd-1-3.5.0 676.52 -2.7% 658.38 lkp-nex04/RAID0-12HDD-thresh=1000M/ext4-10dd-1-3.5.0 512.70 +4.0% 533.22 lkp-nex04/RAID0-12HDD-thresh=1000M/ext4-1dd-1-3.5.0 524.61 -0.3% 522.90 lkp-nex04/RAID0-12HDD-thresh=1000M/ext4-1dd-2-3.5.0 709.76 -15.7% 598.44 lkp-nex04/RAID0-12HDD-thresh=100M/ext4-100dd-1-3.5.0 681.39 -2.1% 667.25 lkp-nex04/RAID0-12HDD-thresh=100M/ext4-10dd-1-3.5.0 524.16 +0.8% 528.25 lkp-nex04/RAID0-12HDD-thresh=100M/ext4-1dd-2-3.5.0 699.77 -19.2% 565.54 lkp-nex04/RAID0-12HDD-thresh=8G/ext4-100dd-1-3.5.0 675.79 -1.9% 663.17 lkp-nex04/RAID0-12HDD-thresh=8G/ext4-10dd-1-3.5.0 484.84 -7.4% 448.83 lkp-nex04/RAID0-12HDD-thresh=8G/ext4-1dd-1-3.5.0 470.40 -3.2% 455.31 lkp-nex04/RAID0-12HDD-thresh=8G/ext4-1dd-2-3.5.0 167.97 -38.7% 103.03 lkp-nex04/RAID5-12HDD-thresh=1000M/ext4-100dd-1-3.5.0 243.67 -9.1% 221.41 lkp-nex04/RAID5-12HDD-thresh=1000M/ext4-10dd-1-3.5.0 248.98 +12.2% 279.33 lkp-nex04/RAID5-12HDD-thresh=1000M/ext4-1dd-1-3.5.0 208.45 +14.1% 237.86 lkp-nex04/RAID5-12HDD-thresh=1000M/ext4-1dd-2-3.5.0 71.18 -34.2% 46.82 lkp-nex04/RAID5-12HDD-thresh=100M/ext4-100dd-1-3.5.0 145.84 -7.3% 135.25 lkp-nex04/RAID5-12HDD-thresh=100M/ext4-10dd-1-3.5.0 255.22 +6.7% 272.35 lkp-nex04/RAID5-12HDD-thresh=100M/ext4-1dd-1-3.5.0 243.09 +20.7% 293.30 lkp-nex04/RAID5-12HDD-thresh=100M/ext4-1dd-2-3.5.0 209.24 -23.6% 159.96 lkp-nex04/RAID5-12HDD-thresh=8G/ext4-100dd-1-3.5.0 243.73 -10.9% 217.28 lkp-nex04/RAID5-12HDD-thresh=8G/ext4-10dd-1-3.5.0 214.25 +5.6% 226.32 lkp-nex04/RAID5-12HDD-thresh=8G/ext4-1dd-1-3.5.0 207.16 +13.4% 234.98 lkp-nex04/RAID5-12HDD-thresh=8G/ext4-1dd-2-3.5.0 17572.12 -1.9% 17240.05 TOTAL write_bw Thanks, Fengguang -- 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/