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 A1544C001DF for ; Fri, 4 Aug 2023 13:40:00 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qRv1r-0002NQ-UW; Fri, 04 Aug 2023 09:39:43 -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 1qRv1q-0002Mo-4V for qemu-devel@nongnu.org; Fri, 04 Aug 2023 09:39:42 -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 1qRv1i-0001v6-He for qemu-devel@nongnu.org; Fri, 04 Aug 2023 09:39:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1691156362; 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:in-reply-to:in-reply-to: references:references; bh=qFiwBAeM/ffqHiVVGuLOSQ7USRY7Ej9FOzAzPadXqus=; b=C3PJDGXAC7IvWFZ9d9GLvyj0kWcot8wobgHZ3hnmfmq9UmeEtb17OSYtAXbfIXWV534ZYx KFuJ0KroUIgEmbwCL28Tldkfv3qzK2U3wpyU7NFggBPOmUPYQwvCOkXbVRibvBfE24O5pJ NIMV0QGDwV+3xEtXPx67aFCPQnib764= 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-345-jA2LgF7mPXS4Hi9eZNbGDw-1; Fri, 04 Aug 2023 09:39:21 -0400 X-MC-Unique: jA2LgF7mPXS4Hi9eZNbGDw-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 6233883505A; Fri, 4 Aug 2023 13:39:19 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.105]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D4C6E40C2078; Fri, 4 Aug 2023 13:39:17 +0000 (UTC) Date: Fri, 4 Aug 2023 14:39:15 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Peter Xu Cc: Markus Armbruster , qemu-devel@nongnu.org, Leonardo Bras Soares Passos , Eric Blake , Juan Quintela , Chensheng Dong , Zhiyi Guo , Fabiano Rosas Subject: Re: [PATCH] migration: Allow user to specify migration available bandwidth Message-ID: References: <20230724170755.1114519-1-peterx@redhat.com> <87351cfdrq.fsf@pond.sub.org> <87o7jz8a6o.fsf@pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/2.2.9 (2022-11-12) X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 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 Wed, Jul 26, 2023 at 11:12:31AM -0400, Peter Xu wrote: > On Wed, Jul 26, 2023 at 08:21:35AM +0200, Markus Armbruster wrote: > > Peter Xu writes: > > > > > Hi, Markus, > > > > > > On Tue, Jul 25, 2023 at 01:10:01PM +0200, Markus Armbruster wrote: > > > > [...] > > > > >> For better or worse, we duplicate full documentation between > > >> MigrationParameter, MigrateSetParameters, and MigrationParameters. This > > >> would be the first instance where we reference instead. I'm not opposed > > >> to use references, but if we do, I want them used consistently. > > > > > > We discussed this over the other "switchover" parameter, but that patchset > > > just stranded.. > > > > > > Perhaps I just provide a pre-requisite patch to remove all the comments in > > > MigrateSetParameters and MigrationParameters, letting them all point to > > > MigrationParameter? > > > > Simplifies maintaining the doc commments. But how does it affect the > > documentation generated from it? Better, neutral, or worse? > > Probably somewhere neutral. There are definitely benefits, shorter > > man/html page in total, and avoid accidentally different docs over the same > fields. E.g., we sometimes have different wordings for different objects: > > max-cpu-throttle > maximum cpu throttle percentage. Defaults to 99. (Since 3.1) > > max-cpu-throttle: int (optional) > maximum cpu throttle percentage. The default value is 99. (Since 3.1) > > This one is fine, but it's just very easy to leak in something that shows > differently. It's good to provide coherent documentation for the same > fields over all three objects. Do we have any actual problems though where the difference in docs is actively harmful ? I agree there's a possbility of the duplication being problematic, but unless its actually the case in reality, it is merely a theoretical downside. IMHO for someone consuming the docs, this patch is worse, not neutral. > > When looking at qemu-qmp-ref.7, it can be like this when we can invite the > reader to read the other section (assuming we only keep MigrationParameter > to keep the documentations): > > MigrationParameters (Object) > > The object structure to represent a list of migration parameters. > The optional members aren't actually optional. For detailed > explanation for each of the field, please refer to the documentation > of MigrationParameter. > > But the problem is we always will generate the Members entry, where now > it'll all filled up with "Not documented".. > > Members > announce-initial: int (optional) > Not documented > > announce-max: int (optional) > Not documented > > announce-rounds: int (optional) > Not documented > > [...] > > I think maybe it's better we just list the members without showing "Not > documented" every time for the other two objects. Not sure whether it's an > easy way to fix it, or is it a major issue. > > For developers, dedup the comment should always be a win, afaict. IMHO that's optimizing for the wrong people and isn't a measurable win anyway. Someone adding a new parameter can just cut+paste the same docs string in the three places. It is a cost, but it is a small one time cost, where having "not documented" is a ongoing cost for consumers of our API. I don't think the burden on QEMU maintainers adding new migration parameters is significant enough to justify ripping out our existing docs. 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 :|