From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40220) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cnSvq-0006ya-3N for qemu-devel@nongnu.org; Mon, 13 Mar 2017 12:34:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cnSvn-0001lr-0f for qemu-devel@nongnu.org; Mon, 13 Mar 2017 12:34:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42286) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cnSvm-0001lM-Rv for qemu-devel@nongnu.org; Mon, 13 Mar 2017 12:34:46 -0400 Received: from smtp.corp.redhat.com (int-mx16.intmail.prod.int.phx2.redhat.com [10.5.11.28]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B3B0F3304C4 for ; Mon, 13 Mar 2017 16:34:46 +0000 (UTC) Date: Mon, 13 Mar 2017 16:34:39 +0000 From: "Daniel P. Berrange" Message-ID: <20170313163429.GK4799@redhat.com> Reply-To: "Daniel P. Berrange" References: <20170313124434.1043-1-quintela@redhat.com> <20170313124434.1043-8-quintela@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20170313124434.1043-8-quintela@redhat.com> Subject: Re: [Qemu-devel] [PATCH 07/16] migration: Create x-multifd-group parameter List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Juan Quintela Cc: qemu-devel@nongnu.org, amit.shah@redhat.com, dgilbert@redhat.com On Mon, Mar 13, 2017 at 01:44:25PM +0100, Juan Quintela wrote: > Indicates how many pages we are going to send in each bach to a multifd > thread. > diff --git a/qapi-schema.json b/qapi-schema.json > index b7cb26d..33a6267 100644 > --- a/qapi-schema.json > +++ b/qapi-schema.json > @@ -988,6 +988,9 @@ > # @x-multifd-threads: Number of threads used to migrate data in parallel > # The default value is 2 (since 2.9) > # > +# @x-multifd-group: Number of pages sent together to a thread > +# The default value is 16 (since 2.9) > +# > # Since: 2.4 > ## > { 'enum': 'MigrationParameter', > @@ -995,7 +998,7 @@ > 'cpu-throttle-initial', 'cpu-throttle-increment', > 'tls-creds', 'tls-hostname', 'max-bandwidth', > 'downtime-limit', 'x-checkpoint-delay', > - 'x-multifd-threads'] } > + 'x-multifd-threads', 'x-multifd-group'] } > > ## > # @migrate-set-parameters: > @@ -1062,6 +1065,9 @@ > # @x-multifd-threads: Number of threads used to migrate data in parallel > # The default value is 2 (since 2.9) > # > +# @x-multifd-group: Number of pages sent together in a bunch > +# The default value is 16 (since 2.9) > +# How is this parameter supposed to be used ? Or to put it another way, what are the benefits / effects of changing it from its default value and can an application usefully decide what value to set ? I'm loathe to see us expose another "black magic" parameter where you can't easily determine what values to set, without predicting future guest workloads Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://entangle-photo.org -o- http://search.cpan.org/~danberr/ :|