From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wu Fengguang Subject: Re: [PATCH 00/11] IO-less dirty throttling v12 Date: Wed, 5 Oct 2011 09:42:42 +0800 Message-ID: <20111005014242.GA10237@localhost> References: <20111003134228.090592370@intel.com> <20111003135902.GA16518@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Peter Zijlstra , Andrew Morton , Jan Kara , Christoph Hellwig , Dave Chinner , Greg Thelen , Minchan Kim , Vivek Goyal , Andrea Righi , linux-mm , LKML To: "linux-fsdevel@vger.kernel.org" Return-path: Content-Disposition: inline In-Reply-To: <20111003135902.GA16518@localhost> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org > As far as I can tell from the current test results, > the writeback performance mostly stays on par with vanilla 3.1 kernel > except for -14% regression on average for NFS, which can be cut down > to -7% by limiting the commit size. I find that the overall NFS throughput can be improved by 42% when doing the NFS writeback wait queue and limiting the commit size. 3.1.0-rc8-ioless6+ 3.1.0-rc8-nfs-wq-smooth+ ------------------------ ------------------------ 22.43 +79.2% 40.20 NFS-thresh=100M/nfs-10dd-1M-32p-32768M-100M:10-X 28.21 +11.9% 31.58 NFS-thresh=100M/nfs-1dd-1M-32p-32768M-100M:10-X 29.21 +54.0% 44.98 NFS-thresh=100M/nfs-2dd-1M-32p-32768M-100M:10-X 14.12 +31.0% 18.50 NFS-thresh=10M/nfs-10dd-1M-32p-32768M-10M:10-X 29.44 +2.1% 30.06 NFS-thresh=10M/nfs-1dd-1M-32p-32768M-10M:10-X 9.09 +231.0% 30.07 NFS-thresh=10M/nfs-2dd-1M-32p-32768M-10M:10-X 25.68 +88.6% 48.43 NFS-thresh=1G/nfs-10dd-1M-32p-32768M-1024M:10-X 41.06 +14.9% 47.16 NFS-thresh=1G/nfs-1dd-1M-32p-32768M-1024M:10-X 39.13 +26.7% 49.56 NFS-thresh=1G/nfs-2dd-1M-32p-32768M-1024M:10-X 238.38 +42.9% 340.54 TOTAL The theoretic explanation could be, one smooths out the NFS write requests and the other smooths out the NFS commits, hence yielding better utilized network/disk pipeline. As a result, the -14% regression can be turned around into 23% speedup comparing to vanilla kernel: 3.1.0-rc4-vanilla+ 3.1.0-rc8-nfs-wq-smooth+ ------------------------ ------------------------ 20.89 +92.5% 40.20 NFS-thresh=100M/nfs-10dd-1M-32p-32768M-100M:10-X 39.43 -19.9% 31.58 NFS-thresh=100M/nfs-1dd-1M-32p-32768M-100M:10-X 26.60 +69.1% 44.98 NFS-thresh=100M/nfs-2dd-1M-32p-32768M-100M:10-X 12.70 +45.7% 18.50 NFS-thresh=10M/nfs-10dd-1M-32p-32768M-10M:10-X 27.41 +9.7% 30.06 NFS-thresh=10M/nfs-1dd-1M-32p-32768M-10M:10-X 26.52 +13.4% 30.07 NFS-thresh=10M/nfs-2dd-1M-32p-32768M-10M:10-X 40.70 +19.0% 48.43 NFS-thresh=1G/nfs-10dd-1M-32p-32768M-1024M:10-X 45.28 +4.2% 47.16 NFS-thresh=1G/nfs-1dd-1M-32p-32768M-1024M:10-X 35.74 +38.7% 49.56 NFS-thresh=1G/nfs-2dd-1M-32p-32768M-1024M:10-X 275.28 +23.7% 340.54 TOTAL The tests don't cover disk arrays on the server side, however it does test various combinations of memory:bandwidth ratio. Thanks, Fengguang -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org