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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id ADDB0C433FE for ; Wed, 5 Oct 2022 15:24:03 +0000 (UTC) Received: from localhost ([::1]:45690 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1og6Fe-00005a-KH for qemu-devel@archiver.kernel.org; Wed, 05 Oct 2022 11:24:02 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:39548) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1og6Aj-00050w-0V for qemu-devel@nongnu.org; Wed, 05 Oct 2022 11:19:06 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:49796) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1og6Ae-0005E3-Nl for qemu-devel@nongnu.org; Wed, 05 Oct 2022 11:18:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1664983130; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Zfihwp7hCMsYuKH3Ifw6o/3trUXDtaB1YA1yCz7d5/M=; b=H4YVVRs0wlGglIkqwUic4ZyKtSVGfysTsz1nQBV9+r0b8QEhbrqVIcjFhjiDwg9T3319bs YlKCXhvy1mJHetolIvd2v8Mr0XMBl0ShyPobWnH8iqWKHyG932zm9uwpc3rKyHE4nVqAxc wjxj8ut8C7uMLDJhoIzMg9BcsMomyEc= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-674-N-Jcp0ZFPdGSPqKPphLdlA-1; Wed, 05 Oct 2022 11:18:45 -0400 X-MC-Unique: N-Jcp0ZFPdGSPqKPphLdlA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 61A5A1C0A12A; Wed, 5 Oct 2022 15:18:35 +0000 (UTC) Received: from localhost (unknown [10.39.193.70]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8E9F34099B5D; Wed, 5 Oct 2022 15:18:24 +0000 (UTC) Date: Wed, 5 Oct 2022 11:18:22 -0400 From: Stefan Hajnoczi To: Andrey Zhadchenko Cc: qemu-block@nongnu.org, qemu-devel@nongnu.org, kwolf@redhat.com, hreitz@redhat.com, mst@redhat.com, den@virtuozzo.com Subject: Re: [RFC patch 0/1] block: vhost-blk backend Message-ID: References: <20220725205527.313973-1-andrey.zhadchenko@virtuozzo.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="4sXZQH9aJZCGqosi" Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 Received-SPF: pass client-ip=170.10.133.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" --4sXZQH9aJZCGqosi Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Oct 05, 2022 at 12:14:18PM +0300, Andrey Zhadchenko wrote: > On 10/4/22 21:13, Stefan Hajnoczi wrote: > > On Mon, Jul 25, 2022 at 11:55:26PM +0300, Andrey Zhadchenko wrote: > > > Although QEMU virtio-blk is quite fast, there is still some room for > > > improvements. Disk latency can be reduced if we handle virito-blk req= uests > > > in host kernel so we avoid a lot of syscalls and context switches. > > >=20 > > > The biggest disadvantage of this vhost-blk flavor is raw format. > > > Luckily Kirill Thai proposed device mapper driver for QCOW2 format to= attach > > > files as block devices: https://www.spinics.net/lists/kernel/msg42929= 65.html > > >=20 > > > Also by using kernel modules we can bypass iothread limitation and fi= naly scale > > > block requests with cpus for high-performance devices. This is planne= d to be > > > implemented in next version. > >=20 > > Hi Andrey, > > Do you have a new version of this patch series that uses multiple > > threads? > >=20 > > I have been playing with vq-IOThread mapping in QEMU and would like to > > benchmark vhost-blk vs QEMU virtio-blk mq IOThreads: > > https://gitlab.com/stefanha/qemu/-/tree/virtio-blk-mq-iothread-prototype > >=20 > > Thanks, > > Stefan >=20 > Hi Stefan > For now my multi-threaded version is only available for Red Hat 9 5.14.0 > kernel. If you really want you can grab it from here: > https://lists.openvz.org/pipermail/devel/2022-September/079951.html (kern= el) > For QEMU part all you need is adding to vhost_blk_start something like: >=20 > #define VHOST_SET_NWORKERS _IOW(VHOST_VIRTIO, 0x1F, int) > ioctl(s->vhostfd, VHOST_SET_NWORKERS, &nworkers); >=20 > Or you can wait a bit. I should be able to send second versions by the end > of the week (Monday in worst case). Thanks, I will wait for the next revision. 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