From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:35919) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Sf6cd-0001yH-Hq for qemu-devel@nongnu.org; Thu, 14 Jun 2012 05:45:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Sf6cX-0001x9-Sz for qemu-devel@nongnu.org; Thu, 14 Jun 2012 05:45:47 -0400 Received: from e28smtp05.in.ibm.com ([122.248.162.5]:36188) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Sf6cX-0001wf-8v for qemu-devel@nongnu.org; Thu, 14 Jun 2012 05:45:41 -0400 Received: from /spool/local by e28smtp05.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 14 Jun 2012 15:15:33 +0530 Received: from d28av03.in.ibm.com (d28av03.in.ibm.com [9.184.220.65]) by d28relay03.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q5E9jT2Z721336 for ; Thu, 14 Jun 2012 15:15:29 +0530 Received: from d28av03.in.ibm.com (loopback [127.0.0.1]) by d28av03.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q5EFEiVc023781 for ; Fri, 15 Jun 2012 01:14:45 +1000 Message-ID: <1339667122.28851.8.camel@mengcong> From: Cong Meng Date: Thu, 14 Jun 2012 17:45:22 +0800 In-Reply-To: References: <1339582392.24309.15.camel@mengcong> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Subject: Re: [Qemu-devel] IO performance test on the tcm-vhost scsi Reply-To: mc@linux.vnet.ibm.com List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi Cc: stefanha@linux.vnet.ibm.com, linuxram@us.ibm.com, qemu-devel@nongnu.org, "Nicholas A. Bellinger" , target-devel@vger.kernel.org, Anthony Liguori , Paolo Bonzini , Asias He On Thu, 2012-06-14 at 09:30 +0100, Stefan Hajnoczi wrote: > On Wed, Jun 13, 2012 at 11:13 AM, mengcong wrote: > > seq-read seq-write rand-read rand-write > > 8k 256k 8k 256k 8k 256k 8k 256k > > ---------------------------------------------------------------------------- > > bare-metal 67951 69802 67064 67075 1758 29284 1969 26360 > > tcm-vhost-iblock 61501 66575 51775 67872 1011 22533 1851 28216 > > tcm-vhost-pscsi 66479 68191 50873 67547 1008 22523 1818 28304 > > virtio-blk 26284 66737 23373 65735 1724 28962 1805 27774 > > scsi-disk 36013 60289 46222 62527 1663 12992 1804 27670 > > > > > unit: KB/s > > seq-read/write = sequential read/write > > rand-read/write = random read/write > > 8k,256k are blocksize of the IO > > What strikes me is how virtio-blk performs significantly worse than > bare metal and tcm_vhost for seq-read/seq-write 8k. The good > tcm_vhost results suggest that the overhead is not the virtio > interface itself, since tcm_vhost implements virtio-scsi. > > To drill down on the tcm_vhost vs userspace performance gap we need > virtio-scsi userspace results. QEMU needs to use the same block > device as the tcm-vhost-iblock benchmark. > > Cong: Is it possible to collect the virtio-scsi userspace results > using the same block device as tcm-vhost-iblock and -drive > format=raw,aio=native,cache=none? > virtio-scsi-raw 43065 69729 52052 67378 1757 29419 2024 28135 qemu ....\ -drive file=/dev/sdb,format=raw,if=none,id=sdb,cache=none,aio=native \ -device virtio-scsi-pci,id=mcbus \ -device scsi-disk,drive=sdb there is only one scsi HBA. /dev/sdb is the disk on which all tests have been done. Is this what you want? Cong Meng > Stefan >