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 56BAAC05027 for ; Tue, 14 Feb 2023 08:45:35 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pRqwH-0003BD-Sx; Tue, 14 Feb 2023 03:45:25 -0500 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 1pRqw5-00035W-3T for qemu-devel@nongnu.org; Tue, 14 Feb 2023 03:45:21 -0500 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 1pRqw2-0005TP-EE for qemu-devel@nongnu.org; Tue, 14 Feb 2023 03:45:12 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1676364307; 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=TwxsZZgbYTX5OG+rT+P/ho6Dmi2KF3SpeETNDjz2bRs=; b=BGujoSsGurO+7aPZDTO7dSDbD9heaj2lzIHkg5HPPItl1MXj0+0nHM++EdJ2IANT/piGLe z8z+S5seUa+CBQ/LtCHg+SnytnmO9UPw9NWtUbbPNL1HLXjyOyhrLmSDxZwwi8PaQmG8yO TA/3WoVLOudJTBGSi2Fkrmnh4X+1kw4= 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-595-X3tyyMURMdeGmUQPyCwL7A-1; Tue, 14 Feb 2023 03:45:04 -0500 X-MC-Unique: X3tyyMURMdeGmUQPyCwL7A-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id C989818A6467; Tue, 14 Feb 2023 08:45:03 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.192.124]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 25DE2492B03; Tue, 14 Feb 2023 08:45:03 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 05C0B21E6A1F; Tue, 14 Feb 2023 09:45:02 +0100 (CET) From: Markus Armbruster To: Juan Quintela Cc: qemu-devel@nongnu.org, Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , "Dr. David Alan Gilbert" , Eduardo Habkost , Eric Blake , Yanan Wang , Marcel Apfelbaum Subject: Re: [PATCH v5 1/3] multifd: Create property multifd-sync-after-each-section References: <20230213091548.76444-1-quintela@redhat.com> <20230213091548.76444-2-quintela@redhat.com> Date: Tue, 14 Feb 2023 09:45:02 +0100 In-Reply-To: <20230213091548.76444-2-quintela@redhat.com> (Juan Quintela's message of "Mon, 13 Feb 2023 10:15:46 +0100") Message-ID: <87mt5goctt.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 3.1 on 10.11.54.9 Received-SPF: pass client-ip=170.10.129.124; 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_H2=-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 Juan Quintela writes: > We used to synchronize all channels at the end of each RAM section > sent. That is not needed, so preparing to only synchronize once every > full round in latests patches. > > Notice that we initialize the property as true. We will change the > default when we introduce the new mechanism. > > Signed-off-by: Juan Quintela > Reviewed-by: Dr. David Alan Gilbert > Signed-off-by: Juan Quintela > > --- > > Rename each-iteration to after-each-section > > Signed-off-by: Juan Quintela > --- > qapi/migration.json | 10 +++++++++- > migration/migration.h | 1 + > hw/core/machine.c | 1 + > migration/migration.c | 15 +++++++++++++-- > 4 files changed, 24 insertions(+), 3 deletions(-) > > diff --git a/qapi/migration.json b/qapi/migration.json > index c84fa10e86..2907241b9c 100644 > --- a/qapi/migration.json > +++ b/qapi/migration.json > @@ -478,6 +478,13 @@ > # should not affect the correctness of postcopy migration. > # (since 7.1) > # > +# @multifd-sync-after-each-section: Synchronize channels after each > +# section is sent. What does it mean to synchronize channels? When would I want to, and why? > +# We used to do > +# that in the past, but it is > +# suboptimal. This isn't particularly helpful, I'm afraid. > +# Default value is true until all code is in. As far as I can tell, it's actually *unused* for now, and a later patch will put it to use ... > +# (since 8.0) > +# > # Features: > # @unstable: Members @x-colo and @x-ignore-shared are experimental. > # > @@ -492,7 +499,8 @@ > 'dirty-bitmaps', 'postcopy-blocktime', 'late-block-activate', > { 'name': 'x-ignore-shared', 'features': [ 'unstable' ] }, > 'validate-uuid', 'background-snapshot', > - 'zero-copy-send', 'postcopy-preempt'] } > + 'zero-copy-send', 'postcopy-preempt', > + 'multifd-sync-after-each-section'] } > > ## > # @MigrationCapabilityStatus: > diff --git a/migration/migration.h b/migration/migration.h > index 2da2f8a164..cf84520196 100644 > --- a/migration/migration.h > +++ b/migration/migration.h > @@ -424,6 +424,7 @@ int migrate_multifd_channels(void); > MultiFDCompression migrate_multifd_compression(void); > int migrate_multifd_zlib_level(void); > int migrate_multifd_zstd_level(void); > +bool migrate_multifd_sync_after_each_section(void); > > #ifdef CONFIG_LINUX > bool migrate_use_zero_copy_send(void); > diff --git a/hw/core/machine.c b/hw/core/machine.c > index f73fc4c45c..dc86849402 100644 > --- a/hw/core/machine.c > +++ b/hw/core/machine.c > @@ -54,6 +54,7 @@ const size_t hw_compat_7_1_len = G_N_ELEMENTS(hw_compat_7_1); > GlobalProperty hw_compat_7_0[] = { > { "arm-gicv3-common", "force-8-bit-prio", "on" }, > { "nvme-ns", "eui64-default", "on"}, > + { "migration", "multifd-sync-after-each-section", "on"}, > }; > const size_t hw_compat_7_0_len = G_N_ELEMENTS(hw_compat_7_0); > > diff --git a/migration/migration.c b/migration/migration.c > index 90fca70cb7..406c27bc82 100644 > --- a/migration/migration.c > +++ b/migration/migration.c > @@ -167,7 +167,8 @@ INITIALIZE_MIGRATE_CAPS_SET(check_caps_background_snapshot, > MIGRATION_CAPABILITY_XBZRLE, > MIGRATION_CAPABILITY_X_COLO, > MIGRATION_CAPABILITY_VALIDATE_UUID, > - MIGRATION_CAPABILITY_ZERO_COPY_SEND); > + MIGRATION_CAPABILITY_ZERO_COPY_SEND, > + MIGRATION_CAPABILITY_MULTIFD_SYNC_AFTER_EACH_SECTION); > > /* When we add fault tolerance, we could have several > migrations at once. For now we don't need to add > @@ -2701,6 +2702,15 @@ bool migrate_use_multifd(void) > return s->enabled_capabilities[MIGRATION_CAPABILITY_MULTIFD]; > } > > +bool migrate_multifd_sync_after_each_section(void) > +{ > + MigrationState *s = migrate_get_current(); > + > + return true; > + // We will change this when code gets in. > + return s->enabled_capabilities[MIGRATION_CAPABILITY_MULTIFD_SYNC_AFTER_EACH_SECTION]; ... here. No warning about unreachable code? Checking... nope, gcc seems to not to care. > +} > + > bool migrate_pause_before_switchover(void) > { > MigrationState *s; > @@ -4535,7 +4545,8 @@ static Property migration_properties[] = { > DEFINE_PROP_MIG_CAP("x-zero-copy-send", > MIGRATION_CAPABILITY_ZERO_COPY_SEND), > #endif > - > + DEFINE_PROP_MIG_CAP("multifd-sync-after-each-section", > + MIGRATION_CAPABILITY_MULTIFD_SYNC_AFTER_EACH_SECTION), > DEFINE_PROP_END_OF_LIST(), > };