From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Mason Subject: Re: Poor read performance on high-end server Date: Mon, 9 Aug 2010 20:55:39 -0400 Message-ID: <20100810005539.GI10525@think> References: <4C5AC52D.9030906@sara.nl> <20100805145138.GJ29846@think> <4C5BF829.3020200@kernel.dk> <87r5i98tdf.fsf@basil.nowhere.org> <4C5E8F46.5010706@kernel.dk> <4C601499.5040402@sara.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jens Axboe , Andi Kleen , "linux-btrfs@vger.kernel.org" To: Freek Dijkstra Return-path: In-Reply-To: <4C601499.5040402@sara.nl> List-ID: On Mon, Aug 09, 2010 at 04:45:45PM +0200, Freek Dijkstra wrote: > Hi all, > > Thanks a lot for the great feedback from before the weekend. Since one > of my colleagues needed the machine, I could only do the tests today. > > In short: just installing 2.6.35 did make some difference, but I was > mostly impressed with the speedup gained by the hardware acceleration of > the crc32c_intel module. > > Here is some quick data. > > Reference figures: > 16* single disk (theoretical limit): 4092 MiByte/s > fio data layer tests (achievable limit): 3250 MiByte/s > ZFS performance: 2505 MiByte/s > > BtrFS figures: > IOzone on 2.6.32: 919 MiByte/s > fio btrfs tests on 2.6.35: 1460 MiByte/s Was this one with O_DIRECT? > IOzone on 2.6.35 with crc32c: 1250 MiByte/s > IOzone on 2.6.35 with crc32c_intel: 1629 MiByte/s > IOzone on 2.6.35, using -o nodatasum: 1955 MiByte/s > > For those finding this message and want a howto: the easiest way to use > crc32c_intel is to add the module name to /etc/modules: > # echo "crc32c_intel" >> /etc/modules > # reboot > > Now the next step for us is to tune the block sizes. We only did that > preliminary, but now that we have a good knowledge of what software to > use, we can start tuning that in more detail. > > If there is interest on this list, I'll gladly post our results here. Definitely, please do. -chris