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 671DAC00A8F for ; Tue, 24 Oct 2023 05:26:59 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qv9vc-00075R-BI; Tue, 24 Oct 2023 01:26:08 -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 1qv9va-00074G-GA for qemu-devel@nongnu.org; Tue, 24 Oct 2023 01:26:06 -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 1qv9vY-0008Pu-Mi for qemu-devel@nongnu.org; Tue, 24 Oct 2023 01:26:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1698125163; 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: in-reply-to:in-reply-to:references:references; bh=0HEoOnph3bWceyM0BA5dpdgHNmGyrz9LsyrNCMJxMws=; b=KZp9QmN25H+lz88oQ9E25+YVnW2Qkbn7tetu3bhoI348NIamC8ZT6ujvRuE84ksHBo43Of CQhP/6R5JE8LTMLV2KcI9JAZGjzKRodX1g6UXk1MnmwlsCJdW6850jrnINvOFlbvRsEOs/ /1HEc6yagY+Qo57aScGwJ12lp1o4hlA= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-632-Rxwe5XHCNZi2XtFmJ_HNRg-1; Tue, 24 Oct 2023 01:25:59 -0400 X-MC-Unique: Rxwe5XHCNZi2XtFmJ_HNRg-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (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 mimecast-mx02.redhat.com (Postfix) with ESMTPS id 62DB384AEA1; Tue, 24 Oct 2023 05:25:59 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.193.56]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 40B57492BD9; Tue, 24 Oct 2023 05:25:59 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 332DF21E6A1F; Tue, 24 Oct 2023 07:25:58 +0200 (CEST) From: Markus Armbruster To: Fabiano Rosas Cc: qemu-devel@nongnu.org, berrange@redhat.com, Juan Quintela , Peter Xu , Leonardo Bras , Claudio Fontana , Eric Blake Subject: Re: [PATCH v2 06/29] migration: Add auto-pause capability References: <20231023203608.26370-1-farosas@suse.de> <20231023203608.26370-7-farosas@suse.de> Date: Tue, 24 Oct 2023 07:25:58 +0200 In-Reply-To: <20231023203608.26370-7-farosas@suse.de> (Fabiano Rosas's message of "Mon, 23 Oct 2023 17:35:45 -0300") Message-ID: <87r0lkvbfd.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.9 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@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_H3=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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Fabiano Rosas writes: > Add a capability that allows the management layer to delegate to QEMU > the decision of whether to pause a VM and perform a non-live > migration. Depending on the type of migration being performed, this > could bring performance benefits. > > Note that the capability is enabled by default but at this moment no > migration scheme is making use of it. This sounds as if the capability has no effect unless the "migration scheme" (whatever that may be) opts into using it. Am I confused? > Signed-off-by: Fabiano Rosas [...] > diff --git a/qapi/migration.json b/qapi/migration.json > index db3df12d6c..74f12adc0e 100644 > --- a/qapi/migration.json > +++ b/qapi/migration.json > @@ -523,6 +523,10 @@ > # and can result in more stable read performance. Requires KVM > # with accelerator property "dirty-ring-size" set. (Since 8.1) > # > +# @auto-pause: If enabled, allows QEMU to decide whether to pause the > +# VM before migration for an optimal migration performance. > +# Enabled by default. (since 8.1) If this needs an opt-in to take effect, it should be documented. > +# > # Features: > # > # @unstable: Members @x-colo and @x-ignore-shared are experimental. > @@ -539,7 +543,7 @@ > { 'name': 'x-ignore-shared', 'features': [ 'unstable' ] }, > 'validate-uuid', 'background-snapshot', > 'zero-copy-send', 'postcopy-preempt', 'switchover-ack', > - 'dirty-limit'] } > + 'dirty-limit', 'auto-pause'] } > > ## > # @MigrationCapabilityStatus: