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 6BEDBCEACCB for ; Tue, 1 Oct 2024 14:29:56 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1svdqF-0008LT-Eh; Tue, 01 Oct 2024 10:27:13 -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 1svdp6-0007ZX-Da for qemu-devel@nongnu.org; Tue, 01 Oct 2024 10:26:04 -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 1svdov-0006cn-Cs for qemu-devel@nongnu.org; Tue, 01 Oct 2024 10:25:53 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1727792740; 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=hFAooNKd01/7jy/TVgwpCQpkboRyQ3CLsMqdDCLTRzM=; b=gVcUlrH5+15dR03MiVV4x/oJLt4th6Uo7J9TCLuS8AInlGq7ywFJ56EatpQ8tbz+8rCsIh V/k80sBztiGezMtCXK/bEPLa9QAjhjXmHM0siW2Upaxj8Ezw+3GuAVM1bhjgYvAbPTPQ+n GID6J8jYvtevcyrXV9lpXzhInf5kEYY= Received: from mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-473-Vu2TZG6SNUG3Yw-gc51xTw-1; Tue, 01 Oct 2024 10:25:36 -0400 X-MC-Unique: Vu2TZG6SNUG3Yw-gc51xTw-1 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (unknown [10.30.177.12]) (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-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id EC3601955D4C; Tue, 1 Oct 2024 14:25:33 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.186]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 381F21944AA4; Tue, 1 Oct 2024 14:25:17 +0000 (UTC) Date: Tue, 1 Oct 2024 15:25:14 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Markus Armbruster Cc: Peter Xu , qemu-devel@nongnu.org, Prasad Pandit , Julia Suvorova , Fabiano Rosas , Juraj Marcin , "Dr . David Alan Gilbert" Subject: Re: [PATCH 0/7] migration: query-migrationthreads enhancements and cleanups Message-ID: References: <20240930195837.825728-1-peterx@redhat.com> <87o744e5pa.fsf@pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <87o744e5pa.fsf@pond.sub.org> User-Agent: Mutt/2.2.12 (2023-09-09) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 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: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.144, 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_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, 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 Tue, Oct 01, 2024 at 07:46:09AM +0200, Markus Armbruster wrote: > Command query-migrationthreads went in without a QAPI ACK. Issues > review should have caught: > > * Flawed documentation. Fixed in commit e6c60bf02d1. > > * It should have been spelled query-migration-threads. Not worth fixing > now, I guess. > > * What are the use cases? The commit message doesn't tell! If it's > just for debugging, the command should be marked unstable. It is hard to use too. Lets say a mgmt app wants to restrict migration threads to some certain pCPUs. It can't call query-migrationthreads beforehand as the threads don't exist until migration is started. If it calls after migration is started, then there's a window where threads are running on arbitrary pCPUs that QEMU has access to. There's no synchronization point where threads have been created & can be queried, but are not yet sending data (and thus burning CPU time) 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 :|