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 35E84C4345F for ; Thu, 25 Apr 2024 14:18:29 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rzzuk-00076N-0E; Thu, 25 Apr 2024 10:17:34 -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 1rzzua-00074O-GL for qemu-devel@nongnu.org; Thu, 25 Apr 2024 10:17:20 -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 1rzzuX-0001Tv-Dy for qemu-devel@nongnu.org; Thu, 25 Apr 2024 10:17:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1714054633; 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=ats0eIAYHKFvf8DypLJSegocl/XeTCzUE3xREugdd4w=; b=Fy1PcQN6n3rQMao4HdSOKitGu5rSAsYXttW56Zt6VMPyYmuxMw9Jla4Yjv9MpFayYy6UiW fBL18LXEkZoV6s+mBmk8AvyRF3aAGHVoWimt7dcuKUo65w1dmfSoJGcCW/csKgQJt8VWp2 z4h+Idmov6P4hkt03/NS30LczYilnu0= 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-548-f7oEStASP8yregafkbUpSg-1; Thu, 25 Apr 2024 10:17:09 -0400 X-MC-Unique: f7oEStASP8yregafkbUpSg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (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 6F82697AF46; Thu, 25 Apr 2024 14:17:09 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.102]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8AE921121313; Thu, 25 Apr 2024 14:17:07 +0000 (UTC) Date: Thu, 25 Apr 2024 15:17:05 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Hao Xiang Cc: marcandre.lureau@redhat.com, peterx@redhat.com, farosas@suse.de, armbru@redhat.com, lvivier@redhat.com, qemu-devel@nongnu.org Subject: Re: [PATCH v4 08/14] migration/multifd: Add new migration option for multifd DSA offloading. Message-ID: References: <20240425022117.4035031-1-hao.xiang@linux.dev> <20240425022117.4035031-9-hao.xiang@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240425022117.4035031-9-hao.xiang@linux.dev> User-Agent: Mutt/2.2.12 (2023-09-09) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.3 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@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=-0.669, 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 Thu, Apr 25, 2024 at 02:21:11AM +0000, Hao Xiang wrote: > Intel DSA offloading is an optional feature that turns on if > proper hardware and software stack is available. To turn on > DSA offloading in multifd live migration: > > multifd-dsa-accel="[dsa_dev_path1] [dsa_dev_path2] ... [dsa_dev_pathX]" > > This feature is turned off by default. > > Signed-off-by: Hao Xiang > --- > migration/migration-hmp-cmds.c | 8 ++++++++ > migration/options.c | 30 ++++++++++++++++++++++++++++++ > migration/options.h | 1 + > qapi/migration.json | 26 +++++++++++++++++++++++--- > 4 files changed, 62 insertions(+), 3 deletions(-) > diff --git a/qapi/migration.json b/qapi/migration.json > index 8c65b90328..934fa8839e 100644 > --- a/qapi/migration.json > +++ b/qapi/migration.json > @@ -914,6 +914,12 @@ > # See description in @ZeroPageDetection. Default is 'multifd'. > # (since 9.0) > # > +# @multifd-dsa-accel: If enabled, use DSA accelerator offloading for > +# certain memory operations. Enable DSA accelerator offloading by > +# setting this string to a list of DSA device path separated by space > +# characters. Setting this string to an empty string means disabling > +# DSA accelerator offloading. Defaults to an empty string. (since 9.2) Passing a list of paths as a single space separate string is a design anti-pattern. This needs to use a list type at the QAPI level. Also I don't think we need add 'multifd' on the name - all new features are for multifd. Overall it should be called 'dsa-accel-path' I thjink > @@ -1122,6 +1128,12 @@ > # See description in @ZeroPageDetection. Default is 'multifd'. > # (since 9.0) > # > +# @multifd-dsa-accel: If enabled, use DSA accelerator offloading for > +# certain memory operations. Enable DSA accelerator offloading by > +# setting this string to a list of DSA device path separated by space > +# characters. Setting this string to an empty string means disabling > +# DSA accelerator offloading. Defaults to an empty string. (since 9.2) > +# > # Features: > # > # @deprecated: Member @block-incremental is deprecated. Use > @@ -1176,7 +1188,8 @@ > 'features': [ 'unstable' ] }, > '*vcpu-dirty-limit': 'uint64', > '*mode': 'MigMode', > - '*zero-page-detection': 'ZeroPageDetection'} } > + '*zero-page-detection': 'ZeroPageDetection', > + '*multifd-dsa-accel': 'StrOrNull'} } This needs to be ['str'] not 'StrOrNull' > > ## > # @migrate-set-parameters: > @@ -1354,6 +1367,12 @@ > # See description in @ZeroPageDetection. Default is 'multifd'. > # (since 9.0) > # > +# @multifd-dsa-accel: If enabled, use DSA accelerator offloading for > +# certain memory operations. Enable DSA accelerator offloading by > +# setting this string to a list of DSA device path separated by space > +# characters. Setting this string to an empty string means disabling > +# DSA accelerator offloading. Defaults to an empty string. (since 9.2) > +# > # Features: > # > # @deprecated: Member @block-incremental is deprecated. Use > @@ -1405,7 +1424,8 @@ > 'features': [ 'unstable' ] }, > '*vcpu-dirty-limit': 'uint64', > '*mode': 'MigMode', > - '*zero-page-detection': 'ZeroPageDetection'} } > + '*zero-page-detection': 'ZeroPageDetection', > + '*multifd-dsa-accel': 'str'} } Liekewise needs to be ['str'] Having mgmt apps pass in the path every time though, feels like overkill. Surely there's a standard path that QEMU should use by default, and should only require flag to turn on its usage. IOW, why not extend the ZeroPageDetection enum, to have a further entry for 'dsa' to request ue of dsa accel. Passing paths could be optional. 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 :|