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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C1564C54E94 for ; Thu, 26 Jan 2023 03:09:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230177AbjAZDJZ (ORCPT ); Wed, 25 Jan 2023 22:09:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42184 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230140AbjAZDJY (ORCPT ); Wed, 25 Jan 2023 22:09:24 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1829C65ED3 for ; Wed, 25 Jan 2023 19:08:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1674702521; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=EQwcHjEQn5hMKdjvwFglOuFxXiSbeIEOQIHV9+GgT38=; b=OaKEIJlOiaL4AS4Zoom5TG+fJDW0+zrkfy1p1MFEqdbaaGuLysleZYuySx22EOTjfyeVQi KegBYZR/KufQMlxuiYo737MP7QSYkGlwE/EnVnH8ffFy2THVScZ1Xb2UjFqvwvbIITZBbr /iRxW6okrCajdgSvNBA3nOK4zm6C2c0= 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-498-QF9tq1OzNmGt8lxUocwkeQ-1; Wed, 25 Jan 2023 22:08:37 -0500 X-MC-Unique: QF9tq1OzNmGt8lxUocwkeQ-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 3949329ABA09; Thu, 26 Jan 2023 03:08:37 +0000 (UTC) Received: from T590 (ovpn-8-18.pek2.redhat.com [10.72.8.18]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E3BF8492C14; Thu, 26 Jan 2023 03:08:31 +0000 (UTC) Date: Thu, 26 Jan 2023 11:08:26 +0800 From: Ming Lei To: Jens Axboe Cc: io-uring@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, nbd@other.debian.org, ming.lei@redhat.com Subject: Re: ublk-nbd: ublk-nbd is avaialbe Message-ID: References: <4f22f15f-c15f-5fba-1569-3da8c0f37f0e@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <4f22f15f-c15f-5fba-1569-3da8c0f37f0e@kernel.dk> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org Hi Jens, On Thu, Jan 19, 2023 at 11:49:04AM -0700, Jens Axboe wrote: > On 1/19/23 7:23 AM, Ming Lei wrote: > > Hi, > > > > ublk-nbd[1] is available now. > > > > Basically it is one nbd client, but totally implemented in userspace, > > and wrt. current nbd-client in [2], the transmission phase is done > > by linux block nbd driver. > > > > The handshake implementation is borrowed from nbd project[2], so > > basically ublk-nbd just adds new code for implementing transmission > > phase, and it can be thought as moving linux block nbd driver into > > userspace. > > > > The added new code is basically in nbd/tgt_nbd.cpp, and io handling > > is based on liburing[3], and implemented by c++20 coroutine, so > > everything is done in single pthread totally lockless, meantime turns > > out it is pretty easy to design & implement, attributed to ublk framework, > > c++20 coroutine and liburing. > > > > ublk-nbd supports both tcp and unix socket, and allows to enable io_uring > > send zero copy via command line '--send_zc', see details in README[4]. > > > > No regression is found in xfstests by using ublk-nbd as both test device > > and scratch device, and builtin test(make test T=nbd) runs well. > > > > Fio test("make test T=nbd") shows that ublk-nbd performance is > > basically same with nbd-client/nbd driver when running fio on real > > ethernet link(1g, 10+g), but ublk-nbd IOPS is higher by ~40% than > > nbd-client(nbd driver) with 512K BS, which is because linux nbd > > driver sets max_sectors_kb as 64KB at default. > > > > But when running fio over local tcp socket, it is observed in my test > > machine that ublk-nbd performs better than nbd-client/nbd driver, > > especially with 2 queue/2 jobs, and the gap could be 10% ~ 30% > > according to different block size. > > This is pretty nice! Just curious, have you tried setting up your > ring with > > p.flags |= IORING_SETUP_SINGLE_ISSUER | IORING_SETUP_DEFER_TASKRUN; > > and see if that yields any extra performance improvements for you? > Depending on how you do processing, you should not need to do any > further changes there. > > A "lighter" version is just setting IORING_SETUP_COOP_TASKRUN. IORING_SETUP_COOP_TASKRUN is enabled in current ublksrv. After disabling COOP_TASKRUN and enabling SINGLE_ISSUER & DEFER_TASKRUN, not see obvious improvement, meantime regression is observed on 64k rw. Thanks, Ming