From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753572Ab1HAFqu (ORCPT ); Mon, 1 Aug 2011 01:46:50 -0400 Received: from mail-gy0-f174.google.com ([209.85.160.174]:64260 "EHLO mail-gy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752804Ab1HAFqm (ORCPT ); Mon, 1 Aug 2011 01:46:42 -0400 Message-ID: <4E363DB9.70801@gmail.com> Date: Mon, 01 Aug 2011 13:46:33 +0800 From: Liu Yuan User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.18) Gecko/20110617 Thunderbird/3.1.11 MIME-Version: 1.0 To: Badari Pulavarty 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> <4E32F7F2.4080607@us.ibm.com> In-Reply-To: <4E32F7F2.4080607@us.ibm.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 On 07/30/2011 02:12 AM, Badari Pulavarty wrote: > 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. > vhost-blk's that uses Linux AIO also support file-backed images. Actually, I have run Guests both on raw partition and raw file 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 ? > Possibly bypass vfs-layer and translate sg lists from virtio buffer into BIOs would benefit the block-backed device. I'll give it a try later. > 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 > > That's great. Yuan