From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752468Ab1G2SMe (ORCPT ); Fri, 29 Jul 2011 14:12:34 -0400 Received: from e32.co.us.ibm.com ([32.97.110.150]:53923 "EHLO e32.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751292Ab1G2SMc (ORCPT ); Fri, 29 Jul 2011 14:12:32 -0400 Message-ID: <4E32F7F2.4080607@us.ibm.com> Date: Fri, 29 Jul 2011 11:12:02 -0700 From: Badari Pulavarty User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1.16) Gecko/20101125 Thunderbird/3.0.11 MIME-Version: 1.0 To: Liu Yuan CC: Stefan Hajnoczi , "Michael S. Tsirkin" , Rusty Russell , Avi Kivity , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Khoa Huynh Subject: Re: [RFC PATCH]vhost-blk: In-kernel accelerator for virtio block device References: <1311863346-4338-1-git-send-email-namei.unix@gmail.com> <4E325F98.5090308@gmail.com> In-Reply-To: <4E325F98.5090308@gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Liu Yuan, I am glad to see that you started looking at vhost-blk. I did an attempt year ago to improve block performance using vhost-blk approach. http://lwn.net/Articles/379864/ http://lwn.net/Articles/382543/ I will take a closer look at your patchset to find differences and similarities. - I focused on using vfs interfaces in the kernel, so that I can use it for file-backed devices. Our use-case scenario is mostly file-backed images. - In few cases, virtio-blk did outperform vhost-blk -- which was counter intuitive - but couldn't exactly nail down. why ? - I had to implement my own threads for parellism. I see that you are using aio infrastructure to get around it. - In our high scale performance testing, what we found is block-backed device performance is pretty close to bare-metal (91% of bare-metal). vhost-blk didn't add any major benefits to it. I am curious on your performance analysis & data on where you see the gains and why ? Hence I prioritized my work low :( Now that you are interested in driving this, I am happy to work with you and see what vhost-blk brings to the tables. (even if helps us improve virtio-blk). Thanks, Badari