From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C5835C32789 for ; Mon, 5 Nov 2018 03:00:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 803F420827 for ; Mon, 5 Nov 2018 03:00:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 803F420827 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728907AbeKEMSF (ORCPT ); Mon, 5 Nov 2018 07:18:05 -0500 Received: from mx1.redhat.com ([209.132.183.28]:47510 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726125AbeKEMSF (ORCPT ); Mon, 5 Nov 2018 07:18:05 -0500 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 919AC3084293; Mon, 5 Nov 2018 03:00:40 +0000 (UTC) Received: from [10.72.12.184] (ovpn-12-184.pek2.redhat.com [10.72.12.184]) by smtp.corp.redhat.com (Postfix) with ESMTPS id CC6C71726F; Mon, 5 Nov 2018 03:00:28 +0000 (UTC) Subject: Re: [PATCH 0/1] vhost: add vhost_blk driver To: Vitaly Mayatskikh , "Michael S . Tsirkin" Cc: Paolo Bonzini , kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Stefan Hajnoczi References: <20181102182123.29420-1-v.mayatskih@gmail.com> From: Jason Wang Message-ID: <6a7f1668-bf2d-0caa-2efd-c8fab5f1db24@redhat.com> Date: Mon, 5 Nov 2018 11:00:23 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20181102182123.29420-1-v.mayatskih@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.40]); Mon, 05 Nov 2018 03:00:40 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018/11/3 上午2:21, Vitaly Mayatskikh wrote: > vhost_blk is a host-side kernel mode accelerator for virtio-blk. The > driver allows VM to reach a near bare-metal disk performance. See IOPS > numbers below (fio --rw=randread --bs=4k). > > This implementation uses kiocb interface. It is slightly slower than > going directly through bio, but is simpler and also works with disk > images placed on a file system. > > # fio num-jobs > # A: bare metal over block > # B: bare metal over file > # C: virtio-blk over block > # D: virtio-blk over file > # E: vhost-blk bio over block > # F: vhost-blk kiocb over block > # G: vhost-blk kiocb over file > # > # A B C D E F G > > 1 171k 151k 148k 151k 195k 187k 175k > 2 328k 302k 249k 241k 349k 334k 296k > 3 479k 437k 179k 174k 501k 464k 404k > 4 622k 568k 143k 183k 620k 580k 492k > 5 755k 697k 136k 128k 737k 693k 579k > 6 887k 808k 131k 120k 830k 782k 640k > 7 1004k 926k 126k 131k 926k 863k 693k > 8 1099k 1015k 117k 115k 1001k 931k 712k > 9 1194k 1119k 115k 111k 1055k 991k 711k > 10 1278k 1207k 109k 114k 1130k 1046k 695k > 11 1345k 1280k 110k 108k 1119k 1091k 663k > 12 1411k 1356k 104k 106k 1201k 1142k 629k > 13 1466k 1423k 106k 106k 1260k 1170k 607k > 14 1517k 1486k 103k 106k 1296k 1179k 589k > 15 1552k 1543k 102k 102k 1322k 1191k 571k > 16 1480k 1506k 101k 102k 1346k 1202k 566k > > Vitaly Mayatskikh (1): > Add vhost_blk driver > > drivers/vhost/Kconfig | 13 ++ > drivers/vhost/Makefile | 3 + > drivers/vhost/blk.c | 510 +++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 526 insertions(+) > create mode 100644 drivers/vhost/blk.c > Hi: Thanks for the patches. This is not the first attempt for having vhost-blk: - Badari's version: https://lwn.net/Articles/379864/ - Asias' version: https://lwn.net/Articles/519880/ It's better to describe the differences (kiocb vs bio? performance?). E.g if my memory is correct, Asias said it doesn't give much improvement compared with userspace qemu. And what's more important, I believe we tend to use virtio-scsi nowdays. So what's the advantages of vhost-blk over vhost-scsi? Thanks