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=-5.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 025D5C43461 for ; Mon, 12 Apr 2021 14:53:32 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 9178D6044F for ; Mon, 12 Apr 2021 14:53:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9178D6044F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:60970 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lVxwQ-0001N9-Lt for qemu-devel@archiver.kernel.org; Mon, 12 Apr 2021 10:53:30 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:49784) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lVxuM-0008EV-Qt for qemu-devel@nongnu.org; Mon, 12 Apr 2021 10:51:22 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:25033) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lVxuK-0000Cp-Un for qemu-devel@nongnu.org; Mon, 12 Apr 2021 10:51:22 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1618239080; 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=BUHDaIBJfGaEY6MCziThObH1ULoIIOsntI7ZHAqvmDs=; b=eCeosNzoDHyzAQCU7ZHbSsjVTDZuTM9yft3iephOTLVemXfTaHpAuiPiEBaYvygZQJOBNv z+BVg0dy7gaANnPNUnNj6yGq0MKKu/6rnLIeHSEpYv5Xp6gvuY/KqRoC+N/5TMvl3xPk5q wJOuxJOgJllGk2aEx2NvUcdGeK3CuAc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-394-2qmCbR1UOo63-Ksoww1WEg-1; Mon, 12 Apr 2021 10:51:18 -0400 X-MC-Unique: 2qmCbR1UOo63-Ksoww1WEg-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E6172100A24D for ; Mon, 12 Apr 2021 14:51:17 +0000 (UTC) Received: from work-vm (ovpn-115-48.ams2.redhat.com [10.36.115.48]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1CF6E5D6DC; Mon, 12 Apr 2021 14:51:12 +0000 (UTC) Date: Mon, 12 Apr 2021 15:51:10 +0100 From: "Dr. David Alan Gilbert" To: Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= Subject: Re: [RFC PATCH 0/5] mptcp support Message-ID: References: <20210408191159.133644-1-dgilbert@redhat.com> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/2.0.6 (2021-03-06) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 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_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: quintela@redhat.com, armbru@redhat.com, qemu-devel@nongnu.org, kraxel@redhat.com, pabeni@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Daniel P. Berrangé (berrange@redhat.com) wrote: > On Thu, Apr 08, 2021 at 08:11:54PM +0100, Dr. David Alan Gilbert (git) wrote: > > From: "Dr. David Alan Gilbert" > > > > Hi, > > This RFC set adds support for multipath TCP (mptcp), > > in particular on the migration path - but should be extensible > > to other users. > > > > Multipath-tcp is a bit like bonding, but at L3; you can use > > it to handle failure, but can also use it to split traffic across > > multiple interfaces. > > > > Using a pair of 10Gb interfaces, I've managed to get 19Gbps > > (with the only tuning being using huge pages and turning the MTU up). > > > > It needs a bleeding-edge Linux kernel (in some older ones you get > > false accept messages for the subflows), and a C lib that has the > > constants defined (as current glibc does). > > > > To use it you just need to append ,mptcp to an address; > > > > -incoming tcp:0:4444,mptcp > > migrate -d tcp:192.168.11.20:4444,mptcp > > What happens if you only enable mptcp flag on one side of the > stream (whether client or server), does it degrade to boring > old single path TCP, or does it result in an error ? I've just tested this and it matches what pabeni said; it seems to just fall back. > > I had a quick go at trying NBD as well, but I think it needs > > some work with the parsing of NBD addresses. > > In theory this is applicable to anywhere that we use sockets. > Anywhere that is configured with the QAPI SocketAddress / > SocketAddressLegacy type will get it for free AFAICT. That was my hope. > Anywhere that is configured via QemuOpts will need an enhancement. > > IOW, I would think NBD already works if you configure NBD via > QMP with nbd-server-start, or block-export-add. qemu-nbd will > need cli options added. > > The block layer clients for NBD, Gluster, Sheepdog and SSH also > all get it for free when configured va QMP, or -blockdev AFAICT Have you got some examples via QMP? I'd failed trying -drive if=virtio,file=nbd://192.168.11.20:3333,mptcp=on/zero > Legacy blocklayer filename syntax would need extra parsing, or > we can just not bother and say if you want new features, use > blockdev. > > > Overall this is impressively simple. Yeh; lots of small unexpected tidyups that took a while to fix. > It feels like it obsoletes the multifd migration code, at least > if you assume Linux platform and new enough kernel ? > > Except TLS... We already bottleneck on TLS encryption with > a single FD, since userspace encryption is limited to a > single thread. Even without TLS we already run out of CPU, probably on the receiving thread at around 20Gbps; which is a bit meh, compared to multifd which I have seen hit 80Gbps on a particularly well greased 100Gbps connection. Curiously my attempts with multifd+mptcp so far have it being slower than with just mptcp on it's own, not hitting the 20Gbps - not sure why yet. > There is the KTLS feature which offloads TLS encryption/decryption > to the kernel. This benefits even regular single FD performance, > because the encrytion work can be done by the kernel in a separate > thread from the userspace IO syscalls. > > Any idea if KTLS is fully compatible with MPTCP ? If so, then that > would look like it makes it a full replacementfor multifd on Linux. I've not tried kTLS at all yet; as pabeni says, not currently compatible. The otherones I'd like to try are zero-copy offload receive/transmit (again I'm not sure those are compatible). Dave > 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 :| -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK