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 X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 76542C433FF for ; Thu, 1 Aug 2019 02:22:20 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 49205206B8 for ; Thu, 1 Aug 2019 02:22:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 49205206B8 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:45524 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1ht0jT-0002Ww-J1 for qemu-devel@archiver.kernel.org; Wed, 31 Jul 2019 22:22:19 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45476) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1ht0iv-00026y-Ui for qemu-devel@nongnu.org; Wed, 31 Jul 2019 22:21:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ht0iu-0003L8-Q5 for qemu-devel@nongnu.org; Wed, 31 Jul 2019 22:21:45 -0400 Received: from mga12.intel.com ([192.55.52.136]:6289) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ht0iu-0003KG-Hn for qemu-devel@nongnu.org; Wed, 31 Jul 2019 22:21:44 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 31 Jul 2019 19:21:42 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,332,1559545200"; d="scan'208";a="191468188" Received: from richard.sh.intel.com (HELO localhost) ([10.239.159.54]) by fmsmga001.fm.intel.com with ESMTP; 31 Jul 2019 19:21:41 -0700 Date: Thu, 1 Aug 2019 10:21:18 +0800 From: Wei Yang To: Ivan Ren Message-ID: <20190801022118.GA21992@richard> References: <1564464992-22305-1-git-send-email-ivanren@tencent.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1564464992-22305-1-git-send-email-ivanren@tencent.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 192.55.52.136 Subject: Re: [Qemu-devel] [PATCH] migration: always initial ram_counters for a new migration X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Wei Yang Cc: qemu-devel@nongnu.org, dgilbert@redhat.com, quintela@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, Jul 30, 2019 at 01:36:32PM +0800, Ivan Ren wrote: >From: Ivan Ren > >This patch fix a multifd migration bug in migration speed calculation, this >problem can be reproduced as follows: >1. start a vm and give a heavy memory write stress to prevent the vm be > successfully migrated to destination >2. begin a migration with multifd >3. migrate for a long time [actually, this can be measured by transferred bytes] >4. migrate cancel >5. begin a new migration with multifd, the migration will directly run into > migration_completion phase > >Reason as follows: > >Migration update bandwidth and s->threshold_size in function >migration_update_counters after BUFFER_DELAY time: > > current_bytes = migration_total_bytes(s); > transferred = current_bytes - s->iteration_initial_bytes; > time_spent = current_time - s->iteration_start_time; > bandwidth = (double)transferred / time_spent; > s->threshold_size = bandwidth * s->parameters.downtime_limit; > >In multifd migration, migration_total_bytes function return >qemu_ftell(s->to_dst_file) + ram_counters.multifd_bytes. >s->iteration_initial_bytes will be initialized to 0 at every new migration, >but ram_counters is a global variable, and history migration data will be >accumulated. So if the ram_counters.multifd_bytes is big enough, it may lead >pending_size >= s->threshold_size become false in migration_iteration_run >after the first migration_update_counters. > >Signed-off-by: Ivan Ren >--- > migration/migration.c | 15 ++++++++++++++- > migration/savevm.c | 1 + > 2 files changed, 15 insertions(+), 1 deletion(-) > >diff --git a/migration/migration.c b/migration/migration.c >index 8a607fe1e2..d35a6ae6f9 100644 >--- a/migration/migration.c >+++ b/migration/migration.c >@@ -1908,6 +1908,11 @@ static bool migrate_prepare(MigrationState *s, bool blk, bool blk_inc, > } > > migrate_init(s); >+ /* >+ * set ram_counters memory to zero for a >+ * new migration >+ */ >+ memset(&ram_counters, 0, sizeof(ram_counters)); > > return true; > } >@@ -3187,6 +3192,10 @@ static void *migration_thread(void *opaque) > > object_ref(OBJECT(s)); > s->iteration_start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); >+ /* >+ * Update s->iteration_initial_bytes to match s->iteration_start_time. >+ */ >+ s->iteration_initial_bytes = migration_total_bytes(s); Is this one necessary? We have sent out nothing yet. > > qemu_savevm_state_header(s->to_dst_file); > >@@ -3252,7 +3261,11 @@ static void *migration_thread(void *opaque) > * breaking transferred_bytes and bandwidth calculation > */ > s->iteration_start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); >- s->iteration_initial_bytes = 0; >+ /* >+ * Update s->iteration_initial_bytes to current size to >+ * avoid historical data lead wrong bandwidth. >+ */ >+ s->iteration_initial_bytes = migration_total_bytes(s); > } > > current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); >diff --git a/migration/savevm.c b/migration/savevm.c >index 79ed44d475..480c511b19 100644 >--- a/migration/savevm.c >+++ b/migration/savevm.c >@@ -1424,6 +1424,7 @@ static int qemu_savevm_state(QEMUFile *f, Error **errp) > } > > migrate_init(ms); >+ memset(&ram_counters, 0, sizeof(ram_counters)); > ms->to_dst_file = f; > > qemu_mutex_unlock_iothread(); >-- >2.17.2 (Apple Git-113) > -- Wei Yang Help you, Help me