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 1625DC2D0CD for ; Mon, 19 May 2025 10:47:27 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uGy1g-0002xr-Vd; Mon, 19 May 2025 06:47:21 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uGy1Z-0002w8-Hr for qemu-devel@nongnu.org; Mon, 19 May 2025 06:47:13 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uGy1X-00017O-AH for qemu-devel@nongnu.org; Mon, 19 May 2025 06:47:13 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1747651629; h=from:from:reply-to: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=ebm9MkWDrXGygQadZdiccrmdm0W5lJn9NLUHewGJbC0=; b=LPIMFnUlMPIZ8AbzbllyYpStXol3OH++oqBdc7YXCE6z9HTM2A8xvNX0RblrtA/HT7HOqj 5kUA84SuXp/QSVGrlOTBmbvHO2YKOcrp1I4ILCWILXUJD1ahkfwUbLrKLQJbbqOlkwRmNd cnNeimCnfjKAh+e/Qzztkx2pj04bw28= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-270-_X8tbKoYNG-cf6P6HnKKYw-1; Mon, 19 May 2025 06:47:07 -0400 X-MC-Unique: _X8tbKoYNG-cf6P6HnKKYw-1 X-Mimecast-MFC-AGG-ID: _X8tbKoYNG-cf6P6HnKKYw_1747651626 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 820EE180087F; Mon, 19 May 2025 10:47:06 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.50]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id E8D4718003FD; Mon, 19 May 2025 10:47:03 +0000 (UTC) Date: Mon, 19 May 2025 11:47:00 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Nir Soffer Cc: qemu-devel@nongnu.org, Eric Blake , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Richard Jones , Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org Subject: Re: [PATCH v4 2/3] nbd: Set unix socket send buffer on macOS Message-ID: References: <20250517201154.88456-1-nirsof@gmail.com> <20250517201154.88456-3-nirsof@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20250517201154.88456-3-nirsof@gmail.com> User-Agent: Mutt/2.2.14 (2025-02-20) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.13, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=-1, RCVD_IN_MSPIKE_WL=-0.01, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Sat, May 17, 2025 at 11:11:53PM +0300, Nir Soffer wrote: > On macOS we need to increase unix socket buffers size on the client and > server to get good performance. We set socket buffers on macOS after > connecting or accepting a client connection. > > Testing shows that setting socket receive buffer size (SO_RCVBUF) has no > effect on performance, so we set only the send buffer size (SO_SNDBUF). > It seems to work like Linux but not documented. > > Testing shows that optimal buffer size is 512k to 4 MiB, depending on > the test case. The difference is very small, so I chose 2 MiB. > > I tested reading from qemu-nbd and writing to qemu-nbd with qemu-img and > computing a blkhash with nbdcopy and blksum. > > To focus on NBD communication and get less noisy results, I tested > reading and writing to null-co driver. I added a read-pattern option to > the null-co driver to return data full of 0xff: > > NULL="json:{'driver': 'raw', 'file': {'driver': 'null-co', 'size': '10g', 'read-pattern': 255}}" > > For testing buffer size I added an environment variable for setting the > socket buffer size. > > Read from qemu-nbd via qemu-img convert. In this test buffer size of 2m > is optimal (12.6 times faster). > > qemu-nbd -r -t -e 0 -f raw -k /tmp/nbd.sock "$NULL" & > qemu-img convert -f raw -O raw -W -n "nbd+unix:///?socket=/tmp/nbd.sock" "$NULL" > > | buffer size | time | user | system | > |-------------|---------|---------|---------| > | default | 13.361 | 2.653 | 5.702 | > | 65536 | 2.283 | 0.204 | 1.318 | > | 131072 | 1.673 | 0.062 | 1.008 | > | 262144 | 1.592 | 0.053 | 0.952 | > | 524288 | 1.496 | 0.049 | 0.887 | > | 1048576 | 1.234 | 0.047 | 0.738 | > | 2097152 | 1.060 | 0.080 | 0.602 | > | 4194304 | 1.061 | 0.076 | 0.604 | > > Write to qemu-nbd with qemu-img convert. In this test buffer size of 2m > is optimal (9.2 times faster). > > qemu-nbd -t -e 0 -f raw -k /tmp/nbd.sock "$NULL" & > qemu-img convert -f raw -O raw -W -n "$NULL" "nbd+unix:///?socket=/tmp/nbd.sock" > > | buffer size | time | user | system | > |-------------|---------|---------|---------| > | default | 8.063 | 2.522 | 4.184 | > | 65536 | 1.472 | 0.430 | 0.867 | > | 131072 | 1.071 | 0.297 | 0.654 | > | 262144 | 1.012 | 0.239 | 0.587 | > | 524288 | 0.970 | 0.201 | 0.514 | > | 1048576 | 0.895 | 0.184 | 0.454 | > | 2097152 | 0.877 | 0.174 | 0.440 | > | 4194304 | 0.944 | 0.231 | 0.535 | > > Compute a blkhash with nbdcopy, using 4 NBD connections and 256k request > size. In this test buffer size of 4m is optimal (5.1 times faster). > > qemu-nbd -r -t -e 0 -f raw -k /tmp/nbd.sock "$NULL" & > nbdcopy --blkhash "nbd+unix:///?socket=/tmp/nbd.sock" null: > > | buffer size | time | user | system | > |-------------|---------|---------|---------| > | default | 8.624 | 5.727 | 6.507 | > | 65536 | 2.563 | 4.760 | 2.498 | > | 131072 | 1.903 | 4.559 | 2.093 | > | 262144 | 1.759 | 4.513 | 1.935 | > | 524288 | 1.729 | 4.489 | 1.924 | > | 1048576 | 1.696 | 4.479 | 1.884 | > | 2097152 | 1.710 | 4.480 | 1.763 | > | 4194304 | 1.687 | 4.479 | 1.712 | > > Compute a blkhash with blksum, using 1 NBD connection and 256k read > size. In this test buffer size of 512k is optimal (10.3 times faster). > > qemu-nbd -r -t -e 0 -f raw -k /tmp/nbd.sock "$NULL" & > blksum "nbd+unix:///?socket=/tmp/nbd.sock" > > | buffer size | time | user | system | > |-------------|---------|---------|---------| > | default | 13.085 | 5.664 | 6.461 | > | 65536 | 3.299 | 5.106 | 2.515 | > | 131072 | 2.396 | 4.989 | 2.069 | > | 262144 | 1.607 | 4.724 | 1.555 | > | 524288 | 1.271 | 4.528 | 1.224 | > | 1048576 | 1.294 | 4.565 | 1.333 | > | 2097152 | 1.299 | 4.569 | 1.344 | > | 4194304 | 1.291 | 4.559 | 1.327 | > > Signed-off-by: Nir Soffer > --- > nbd/client-connection.c | 3 +++ > nbd/common.c | 25 +++++++++++++++++++++++++ > nbd/nbd-internal.h | 5 +++++ > nbd/server.c | 2 ++ > 4 files changed, 35 insertions(+) Reviewed-by: Daniel P. Berrangé With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|