From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53877) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZkEFJ-0007aW-MU for qemu-devel@nongnu.org; Thu, 08 Oct 2015 12:41:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZkEED-0001yM-61 for qemu-devel@nongnu.org; Thu, 08 Oct 2015 12:40:45 -0400 Received: from relay.parallels.com ([195.214.232.42]:41533) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZkEEC-0001tP-Rg for qemu-devel@nongnu.org; Thu, 08 Oct 2015 12:39:37 -0400 References: <5614531B.5080107@redhat.com> <1444198846-5383-1-git-send-email-den@openvz.org> <1444198846-5383-7-git-send-email-den@openvz.org> <5614E995.8010406@redhat.com> From: "Denis V. Lunev" Message-ID: <56169C3D.3060207@openvz.org> Date: Thu, 8 Oct 2015 19:39:25 +0300 MIME-Version: 1.0 In-Reply-To: <5614E995.8010406@redhat.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 6/8] migration: implementation of hook_ram_sync List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: Igor Redko , jsnow@redhat.com, qemu-devel@nongnu.org, annam@virtuozzo.com On 10/07/2015 12:44 PM, Paolo Bonzini wrote: > > On 07/10/2015 08:20, Denis V. Lunev wrote: >> + if (migrate_is_test()) { >> + /* since no data is transfered during estimation all >> + all measurements below will be incorrect. >> + as well no need for delays. */ >> + continue; >> + } > By applying delays, you can also test migration using bandwidth > limitations and try to estimate whether it will converge or not. > Perhaps if you use writev_buffer to implement the test QEMUFile you do > not need this anymore. > > Paolo you see, your proposal would be better for emulation approach. In this case the 'test' will take much more time and may be it will be better for testing purpose. Here we are solving a bit different problem. We are trying to collect reasonable data to make a prediction for migration time and downtime for cluster or cloud management where VMs are hosted on different physical hosts and are migrated from one host to another using different policies. In this case we need to make an estimate to check migration feasibility and it would be nice if we will be able to achieve this goal in the minimal period of time with a minimal overhead :))) OK, this sounds a bit trivial :) On the other hand this code could be used for testing that is why I have spoken about this set. Den