Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756081Ab2ECOIm (ORCPT ); Thu, 3 May 2012 10:08:42 -0400 Received: from mga11.intel.com ([192.55.52.93]:1828 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753807Ab2ECOIk (ORCPT ); Thu, 3 May 2012 10:08:40 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,315,1320652800"; d="scan'208";a="148931606" Date: Thu, 3 May 2012 22:08:27 +0800 From: Fengguang Wu To: Chris Mason Cc: Jan Kara , Andrew Morton , Jeff Moyer , Jens Axboe , linux-fsdevel@vger.kernel.org, LKML , Dave Chinner , Christoph Hellwig , Shaohua Li Subject: Re: [PATCH] btrfs: lower metadata writeback threshold on low dirty threshold Message-ID: <20120503140827.GA24981@localhost> References: <20120408010600.GA31377@localhost> <20120411161344.309f12ef.akpm@linux-foundation.org> <20120412013224.GA5859@localhost> <20120412022040.GA6800@localhost> <20120412142634.GA16559@quack.suse.cz> <20120413014026.GA9027@localhost> <20120503034311.GA14081@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120503034311.GA14081@localhost> 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: 2202 Lines: 37 On Thu, May 03, 2012 at 11:43:11AM +0800, Fengguang Wu wrote: > This helps write performance when setting the dirty threshold to tiny numbers. > > 3.4.0-rc2 3.4.0-rc2-btrfs4+ > ------------ ------------------------ > 96.92 -0.4% 96.54 bay/thresh=1000M/btrfs-100dd-1-3.4.0-rc2 > 98.47 +0.0% 98.50 bay/thresh=1000M/btrfs-10dd-1-3.4.0-rc2 > 99.38 -0.3% 99.06 bay/thresh=1000M/btrfs-1dd-1-3.4.0-rc2 > 98.04 -0.0% 98.02 bay/thresh=100M/btrfs-100dd-1-3.4.0-rc2 > 98.68 +0.3% 98.98 bay/thresh=100M/btrfs-10dd-1-3.4.0-rc2 > 99.34 -0.0% 99.31 bay/thresh=100M/btrfs-1dd-1-3.4.0-rc2 > ==> 88.98 +9.6% 97.53 bay/thresh=10M/btrfs-10dd-1-3.4.0-rc2 > ==> 86.99 +13.1% 98.39 bay/thresh=10M/btrfs-1dd-1-3.4.0-rc2 > ==> 2.75 +2442.4% 69.88 bay/thresh=1M/btrfs-10dd-1-3.4.0-rc2 > ==> 3.31 +2634.1% 90.54 bay/thresh=1M/btrfs-1dd-1-3.4.0-rc2 Well, further tests show that it behaves very unstable: 3.4.0-rc2-btrfs4+ 3.4.0-rc2-btrfs5+ ------------------------ ------------------------ 69.88 +16.4% 81.31 bay/thresh=1M/btrfs-10dd-1-3.4.0-rc2-btrfs4+ 71.09 +1.4% 72.05 bay/thresh=1M/btrfs-10dd-2-3.4.0-rc2-btrfs4+ 72.60 -1.7% 71.38 bay/thresh=1M/btrfs-10dd-3-3.4.0-rc2-btrfs4+ 90.54 -0.9% 89.74 bay/thresh=1M/btrfs-1dd-1-3.4.0-rc2-btrfs4+ 89.17 -90.2% ==> 8.71 bay/thresh=1M/btrfs-1dd-2-3.4.0-rc2-btrfs4+ ==> 14.96 +495.3% 89.06 bay/thresh=1M/btrfs-1dd-3-3.4.0-rc2-btrfs4+ 408.23 +1.0% 412.26 TOTAL write_bw Where the -btrfs5 kernel has one more patch to remove the write plug. 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/