From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40659) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zjauc-0006sA-E8 for qemu-devel@nongnu.org; Tue, 06 Oct 2015 18:40:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZjauZ-0004xl-9n for qemu-devel@nongnu.org; Tue, 06 Oct 2015 18:40:46 -0400 Received: from relay.parallels.com ([195.214.232.42]:57459) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZjauY-0004x5-Vo for qemu-devel@nongnu.org; Tue, 06 Oct 2015 18:40:43 -0400 References: <56141712.1010202@redhat.com> From: "Denis V. Lunev" Message-ID: <56144DDD.9040304@parallels.com> Date: Wed, 7 Oct 2015 01:40:29 +0300 MIME-Version: 1.0 In-Reply-To: <56141712.1010202@redhat.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] Debugging Migration List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: John Snow , qemu-devel Cc: "Dr. David Alan Gilbert" On 10/06/2015 09:46 PM, John Snow wrote: > Is there a convenient way of "pausing" or stalling a live migration to > allow methodical testing of race conditions? > > I'd like to instrument something along the lines of: > > (1) Live migration begins. > (2) migration is artificially halted or paused, but QEMU is allowed to run. > (3) Some additional qtest/QMP commands are received and processed. > (4) migration is allowed to resume. > > Does anyone have perhaps even test patches to instrument this sort of > thing, or is it up to detective john to add it if he wants it? > > Thanks, > --js > we have performed some experiments with migration "test mode". The idea was to estimate the time to migrate and estimate expected downtime for distributed resource management. In this mode the migration was not performed but all stuff around like dirty bitmap was touched. There are several patches for this in my queue but they are very hackish. Will it help you? Den