From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1KpQsE-0001ri-FA for qemu-devel@nongnu.org; Mon, 13 Oct 2008 13:06:26 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1KpQsD-0001qq-Mw for qemu-devel@nongnu.org; Mon, 13 Oct 2008 13:06:26 -0400 Received: from [199.232.76.173] (port=50698 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1KpQsD-0001qX-Hr for qemu-devel@nongnu.org; Mon, 13 Oct 2008 13:06:25 -0400 Received: from e36.co.us.ibm.com ([32.97.110.154]:48132) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1KpQsD-0006xJ-87 for qemu-devel@nongnu.org; Mon, 13 Oct 2008 13:06:25 -0400 Received: from d03relay04.boulder.ibm.com (d03relay04.boulder.ibm.com [9.17.195.106]) by e36.co.us.ibm.com (8.13.8/8.13.8) with ESMTP id m9DH6KGG018280 for ; Mon, 13 Oct 2008 13:06:20 -0400 Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by d03relay04.boulder.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id m9DH6H18175550 for ; Mon, 13 Oct 2008 11:06:17 -0600 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m9DH6B8I010586 for ; Mon, 13 Oct 2008 11:06:17 -0600 Date: Mon, 13 Oct 2008 12:06:10 -0500 From: Ryan Harper Message-ID: <20081013170610.GF21410@us.ibm.com> References: <48EE38B9.2050106@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <48EE38B9.2050106@codemonkey.ws> Subject: [Qemu-devel] Re: [RFC] Disk integrity in QEMU Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Chris Wright , Mark McLoughlin , kvm-devel , Laurent Vivier , "qemu-devel@nongnu.org" , Ryan Harper * Anthony Liguori [2008-10-09 12:00]: > Read performance should be unaffected by using O_DSYNC. O_DIRECT will > significantly reduce read performance. I think we should use O_DSYNC by > default and I have sent out a patch that contains that. We will follow > up with benchmarks to demonstrate this. baremetal baseline (1g dataset): ---------------------------+-------+-------+--------------+------------+ Test scenarios | bandw | % CPU | ave submit | ave compl | type, block size, iface | MB/s | usage | latency usec | latency ms | ---------------------------+-------+-------+--------------+------------+ write, 16k, lvm, direct=1 | 127.7 | 12 | 11.66 | 9.48 | write, 64k, lvm, direct=1 | 178.4 | 5 | 13.65 | 27.15 | write, 1M, lvm, direct=1 | 186.0 | 3 | 163.75 | 416.91 | ---------------------------+-------+-------+--------------+------------+ read , 16k, lvm, direct=1 | 170.4 | 15 | 10.86 | 7.10 | read , 64k, lvm, direct=1 | 199.2 | 5 | 12.52 | 24.31 | read , 1M, lvm, direct=1 | 202.0 | 3 | 133.74 | 382.67 | ---------------------------+-------+-------+--------------+------------+ kvm write (1g dataset): ---------------------------+-------+-------+--------------+------------+ Test scenarios | bandw | % CPU | ave submit | ave compl | block size,iface,cache,sync| MB/s | usage | latency usec | latency ms | ---------------------------+-------+-------+--------------+------------+ 16k,virtio,off,none | 135.0 | 94 | 9.1 | 8.71 | 16k,virtio,on ,none | 184.0 | 100 | 63.69 | 63.48 | 16k,virtio,on ,O_DSYNC | 150.0 | 35 | 6.63 | 8.31 | ---------------------------+-------+-------+--------------+------------+ 64k,virtio,off,none | 169.0 | 51 | 17.10 | 28.00 | 64k,virtio,on ,none | 189.0 | 60 | 69.42 | 24.92 | 64k,virtio,on ,O_DSYNC | 171.0 | 48 | 18.83 | 27.72 | ---------------------------+-------+-------+--------------+------------+ 1M ,virtio,off,none | 142.0 | 30 | 7176.00 | 523.00 | 1M ,virtio,on ,none | 190.0 | 45 | 5332.63 | 392.35 | 1M ,virtio,on ,O_DSYNC | 164.0 | 39 | 6444.48 | 471.20 | ---------------------------+-------+-------+--------------+------------+ kvm read (1g dataset): ---------------------------+-------+-------+--------------+------------+ Test scenarios | bandw | % CPU | ave submit | ave compl | block size,iface,cache,sync| MB/s | usage | latency usec | latency ms | ---------------------------+-------+-------+--------------+------------+ 16k,virtio,off,none | 175.0 | 40 | 22.42 | 6.71 | 16k,virtio,on ,none | 211.0 | 147 | 59.49 | 5.54 | 16k,virtio,on ,O_DSYNC | 212.0 | 145 | 60.45 | 5.47 | ---------------------------+-------+-------+--------------+------------+ 64k,virtio,off,none | 190.0 | 64 | 16.31 | 24.92 | 64k,virtio,on ,none | 546.0 | 161 | 111.06 | 8.54 | 64k,virtio,on ,O_DSYNC | 520.0 | 151 | 116.66 | 8.97 | ---------------------------+-------+-------+--------------+------------+ 1M ,virtio,off,none | 182.0 | 32 | 5573.44 | 407.21 | 1M ,virtio,on ,none | 750.0 | 127 | 1344.65 | 96.42 | 1M ,virtio,on ,O_DSYNC | 768.0 | 123 | 1289.05 | 94.25 | ---------------------------+-------+-------+--------------+------------+ -------------------------------------------------------------------------- exporting file in ext3 filesystem as block device (1g) -------------------------------------------------------------------------- kvm write (1g dataset): ---------------------------+-------+-------+--------------+------------+ Test scenarios | bandw | % CPU | ave submit | ave compl | block size,iface,cache,sync| MB/s | usage | latency usec | latency ms | ---------------------------+-------+-------+--------------+------------+ 16k,virtio,off,none | 12.1 | 15 | 9.1 | 8.71 | 16k,virtio,on ,none | 192.0 | 52 | 62.52 | 6.17 | 16k,virtio,on ,O_DSYNC | 142.0 | 59 | 18.81 | 8.29 | ---------------------------+-------+-------+--------------+------------+ 64k,virtio,off,none | 15.5 | 8 | 21.10 | 311.00 | 64k,virtio,on ,none | 454.0 | 130 | 113.25 | 10.65 | 64k,virtio,on ,O_DSYNC | 154.0 | 48 | 20.25 | 30.75 | ---------------------------+-------+-------+--------------+------------+ 1M ,virtio,off,none | 24.7 | 5 | 41736.22 | 3020.08 | 1M ,virtio,on ,none | 485.0 | 100 | 2052.09 | 149.81 | 1M ,virtio,on ,O_DSYNC | 161.0 | 42 | 6268.84 | 453.84 | ---------------------------+-------+-------+--------------+------------+ -- Ryan Harper Software Engineer; Linux Technology Center IBM Corp., Austin, Tx (512) 838-9253 T/L: 678-9253 ryanh@us.ibm.com