From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:43048) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Sz84k-0004zB-5H for qemu-devel@nongnu.org; Wed, 08 Aug 2012 11:21:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Sz84j-0002Dw-6z for qemu-devel@nongnu.org; Wed, 08 Aug 2012 11:21:34 -0400 Received: from mail.profihost.ag ([85.158.179.208]:34362) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Sz84i-0002Dk-TZ for qemu-devel@nongnu.org; Wed, 08 Aug 2012 11:21:33 -0400 Message-ID: <502283FA.2080506@profihost.ag> Date: Wed, 08 Aug 2012 17:21:30 +0200 From: Stefan Priebe MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] virtio-scsi vs. virtio-blk List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel Hello list, i wanted to start using virtio-scsi instead of virtio-blk, cause it offers the possibility to use discard / trim support. Kernel: 3.5.0 on host and guest Qemu-kvm: 1.1.1 stable But i'm not seeing the same or nearly the same speed: virtio-scsi: rand. 4k: write: io=677628KB, bw=67709KB/s, iops=16927, runt= 10008msec read : io=697648KB, bw=69646KB/s, iops=17411, runt= 10017msec seq 4m: write: io=8192MB, bw=817683KB/s, iops=199, runt= 10259msec read : io=5672MB, bw=565378KB/s, iops=138, runt= 10273msec virtio-blk: rand. 4k: write: io=1750MB, bw=179169KB/s, iops=44792, runt= 10001msec read : io=1388MB, bw=142073KB/s, iops=35518, runt= 10006msec seq 4m: write: io=9776MB, bw=984522KB/s, iops=240, runt= 10168msec read : io=2980MB, bw=288970KB/s, iops=70, runt= 10560msec Any ideas? Greets, Stefan