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 8D5E8CA0FFD for ; Tue, 5 Sep 2023 17:40:41 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qda1a-0007X8-TE; Tue, 05 Sep 2023 13:39:39 -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 1qda1Y-0007PM-Dl for qemu-devel@nongnu.org; Tue, 05 Sep 2023 13:39:36 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qda1T-0004K1-PE for qemu-devel@nongnu.org; Tue, 05 Sep 2023 13:39:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1693935569; 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=zCxp3prKBIMhn0wr2sTTvuKHXcv4EeTeUQzxqsn96b4=; b=WECecZAVIecN73PPjje4vbpIuks7ipYicOl6F/oiUFofF37XuN8OG3t1lV+7uSU2a6wU70 TO5wun6Tkqyel4nuuwtgJCPaClhF3K7GARtmg7w5P8eMt65l/g5+cRosJh90HeefZgKp6h H8EZsxx/TN5wy3C/B+yoDZEuUCq1aFs= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-423-HtWgVSV6P4KDQyFUIAeIkQ-1; Tue, 05 Sep 2023 13:39:27 -0400 X-MC-Unique: HtWgVSV6P4KDQyFUIAeIkQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 82688928E6E; Tue, 5 Sep 2023 17:39:26 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.134]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 32CE31121314; Tue, 5 Sep 2023 17:39:25 +0000 (UTC) Date: Tue, 5 Sep 2023 18:39:23 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Peter Xu Cc: "Wang, Lei" , qemu-devel@nongnu.org, Zhiyi Guo , Markus Armbruster , Leonardo Bras Soares Passos , Fabiano Rosas , Juan Quintela , Eric Blake , Chensheng Dong , Joao Martins Subject: Re: [PATCH for-8.2 v2 2/2] migration: Allow user to specify migration switchover bandwidth Message-ID: References: <20230803155344.11450-1-peterx@redhat.com> <20230803155344.11450-3-peterx@redhat.com> <8bb36b56-e2f6-ece8-0d8f-90b87a3b5c40@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/2.2.9 (2022-11-12) X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@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, 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: 2.1.29 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 Tue, Sep 05, 2023 at 12:46:03PM -0400, Peter Xu wrote: > On Fri, Sep 01, 2023 at 09:37:32AM +0100, Daniel P. Berrangé wrote: > > > > When the user wants to have migration only use 5Gbps out of that 10Gbps, > > > > one can set max-bandwidth to 5Gbps, along with max-switchover-bandwidth to > > > > 5Gbps so it'll never use over 5Gbps too (so the user can have the rest > > > > > > Hi Peter. I'm curious if we specify max-switchover-bandwidth to 5Gbps over a > > > 10Gbps network, in the completion stage will it send the remaining data in 5Gbps > > > using downtime_limit time or in 10Gbps (saturate the network) using the > > > downtime_limit / 2 time? Seems this parameter won't rate limit the final stage:) > > > > Effectively the mgmt app is telling QEMU to assume that this > > much bandwidth is available for use during switchover. If QEMU > > determines that, given this available bandwidth, the remaining > > data can be sent over the link within the downtime limit, it > > will perform the switchover. When sending this sitchover data, > > it will actually transmit the data at full line rate IIUC. > > I'm right at reposting this patch, but then I found that the > max-available-bandwidth is indeed confusing (as Lei's question shows). > > We do have all the bandwidth throttling values in the pattern of > max-*-bandwidth and this one will start to be the outlier that it won't > really throttle the network. > > If the old name "available-bandwidth" is too general, I'm now considering > "avail-switchover-bandwidth" just to leave max- out of the name to > differenciate, if some day we want to add a real throttle for switchover we > can still have a sane name. > > Any objections before I repost? I think the 'avail-' prefix is good given the confusion Lei pointed out. 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 :|