From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44343) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YITft-0006N0-LH for qemu-devel@nongnu.org; Mon, 02 Feb 2015 21:57:14 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YITfq-0000Mb-GN for qemu-devel@nongnu.org; Mon, 02 Feb 2015 21:57:13 -0500 Received: from szxga02-in.huawei.com ([119.145.14.65]:61146) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YITfp-0000LM-VG for qemu-devel@nongnu.org; Mon, 02 Feb 2015 21:57:10 -0500 Message-ID: <54D038EB.9020508@huawei.com> Date: Tue, 3 Feb 2015 10:56:43 +0800 From: "Wangting (Kathy)" MIME-Version: 1.0 References: <54D032FB.404@huawei.com> In-Reply-To: <54D032FB.404@huawei.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [question] the patch which affect performance of virtio-scsi List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: pbonzini@redhat.com Cc: qemu-devel Sorry, I find that the patch of "virtio-scsi: Optimize virtio_scsi_init_req" can slove this problem. By the way, can you tell me the reason of the change about cdb and sense? On 2015-2-3 10:31, Wangting (Kathy) wrote: > Hi Paolo, > > Recently I test IO performance with virtio-scsi, and find out that the patch of > "virtio-scsi: add support for the any_layout feature" affects IO performance of model > with 4KB 32iodepth sequence read. > > Why cdb and sense is removed from the struct of VirtIOSCSICmdReq and VirtIOSCSICmdResp? > How do you consider the impact of the changes to the performance? > Although the latest version of qemu can optimize the performance by the way of reading merger, > I think the affect of this patch cannot be ignored. > > Best wishes, > > Ting >