From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54061) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fDWPp-0006xG-F9 for qemu-devel@nongnu.org; Tue, 01 May 2018 10:38:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fDWPk-000377-5r for qemu-devel@nongnu.org; Tue, 01 May 2018 10:38:01 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:43066) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fDWPj-000365-St for qemu-devel@nongnu.org; Tue, 01 May 2018 10:37:56 -0400 Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w41Ebpdh130507 for ; Tue, 1 May 2018 10:37:51 -0400 Received: from e06smtp15.uk.ibm.com (e06smtp15.uk.ibm.com [195.75.94.111]) by mx0a-001b2d01.pphosted.com with ESMTP id 2hpsme1m67-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 01 May 2018 10:37:51 -0400 Received: from localhost by e06smtp15.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 1 May 2018 15:37:49 +0100 Date: Tue, 1 May 2018 20:07:37 +0530 From: Balamuruhan S References: <20180425071040.25542-1-bala24@linux.vnet.ibm.com> <20180425071040.25542-2-bala24@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180425071040.25542-2-bala24@linux.vnet.ibm.com> Message-Id: <20180501143737.GA25113@9.122.211.20> Subject: Re: [Qemu-devel] [PATCH v3 1/1] migration: calculate expected_downtime with ram_bytes_remaining() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: dgilbert@redhat.com, quintela@redhat.com, david@gibson.dropbear.id.au Cc: qemu-devel@nongnu.org Hi, Dave, David and Juan if you guys are okay with the patch, please help to merge it. Thanks, Bala On Wed, Apr 25, 2018 at 12:40:40PM +0530, Balamuruhan S wrote: > expected_downtime value is not accurate with dirty_pages_rate * page_size, > using ram_bytes_remaining would yeild it correct. It will initially be a > gross over-estimate, but for for non-converging migrations it should > approach a reasonable estimate later on. > > currently bandwidth and expected_downtime value are calculated in > migration_update_counters() during each iteration from > migration_thread(), where as remaining ram is calculated in > qmp_query_migrate() when we actually call "info migrate". Due to this > there is some difference in expected_downtime value being calculated. > > with this patch bandwidth, expected_downtime and remaining ram are > calculated in migration_update_counters(), retrieve the same value during > "info migrate". By this approach we get almost close enough value. > > Reported-by: Michael Roth > Signed-off-by: Balamuruhan S > --- > migration/migration.c | 11 ++++++++--- > migration/migration.h | 1 + > 2 files changed, 9 insertions(+), 3 deletions(-) > > diff --git a/migration/migration.c b/migration/migration.c > index 52a5092add..5d721ee481 100644 > --- a/migration/migration.c > +++ b/migration/migration.c > @@ -614,7 +614,7 @@ static void populate_ram_info(MigrationInfo *info, MigrationState *s) > } > > if (s->state != MIGRATION_STATUS_COMPLETED) { > - info->ram->remaining = ram_bytes_remaining(); > + info->ram->remaining = s->ram_bytes_remaining; > info->ram->dirty_pages_rate = ram_counters.dirty_pages_rate; > } > } > @@ -2227,6 +2227,7 @@ static void migration_update_counters(MigrationState *s, > transferred = qemu_ftell(s->to_dst_file) - s->iteration_initial_bytes; > time_spent = current_time - s->iteration_start_time; > bandwidth = (double)transferred / time_spent; > + s->ram_bytes_remaining = ram_bytes_remaining(); > s->threshold_size = bandwidth * s->parameters.downtime_limit; > > s->mbps = (((double) transferred * 8.0) / > @@ -2237,8 +2238,12 @@ static void migration_update_counters(MigrationState *s, > * recalculate. 10000 is a small enough number for our purposes > */ > if (ram_counters.dirty_pages_rate && transferred > 10000) { > - s->expected_downtime = ram_counters.dirty_pages_rate * > - qemu_target_page_size() / bandwidth; > + /* > + * It will initially be a gross over-estimate, but for for > + * non-converging migrations it should approach a reasonable estimate > + * later on > + */ > + s->expected_downtime = s->ram_bytes_remaining / bandwidth; > } > > qemu_file_reset_rate_limit(s->to_dst_file); > diff --git a/migration/migration.h b/migration/migration.h > index 8d2f320c48..8584f8e22e 100644 > --- a/migration/migration.h > +++ b/migration/migration.h > @@ -128,6 +128,7 @@ struct MigrationState > int64_t downtime_start; > int64_t downtime; > int64_t expected_downtime; > + int64_t ram_bytes_remaining; > bool enabled_capabilities[MIGRATION_CAPABILITY__MAX]; > int64_t setup_time; > /* > -- > 2.14.3 > >