From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36492) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YDoPu-00084O-72 for qemu-devel@nongnu.org; Wed, 21 Jan 2015 01:05:30 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YDoPq-0002Cm-W2 for qemu-devel@nongnu.org; Wed, 21 Jan 2015 01:05:26 -0500 Received: from mx1.redhat.com ([209.132.183.28]:58835) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YDoPq-0002Ci-Nj for qemu-devel@nongnu.org; Wed, 21 Jan 2015 01:05:22 -0500 Date: Wed, 21 Jan 2015 11:35:07 +0530 From: Amit Shah Message-ID: <20150121060507.GS31174@grmbl.mre> References: <1419604968-87437-1-git-send-email-agraf@suse.de> <20150120103112.GI31174@grmbl.mre> <54BE33FA.1000500@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <54BE33FA.1000500@suse.de> Subject: Re: [Qemu-devel] [PATCH v3 0/5] Migration Deciphering aid List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexander Graf Cc: pbonzini@redhat.com, quintela@redhat.com, qemu-devel@nongnu.org, afaerber@suse.de On (Tue) 20 Jan 2015 [11:54:50], Alexander Graf wrote: > > > On 20.01.15 11:31, Amit Shah wrote: > > On (Fri) 26 Dec 2014 [15:42:43], Alexander Graf wrote: > >> Migration is a black hole to most people. One of the biggest reasons for > >> this is that its protocol is a secret, undocumented sauce of code rolling > >> around random parts of the QEMU code base. > >> > >> But what if we simply exposed the description of how the format looks like > >> alongside the actual migration stream? This is what this patch set does. > >> > >> It adds a new section that comes after the end of stream marker (so that it > >> doesn't slow down migration) that contains a JSON description of the device > >> state description. > >> > >> Along with this patch set also comes a python script that can read said JSON > >> from a migration dump and decipher the device state and ram contents of the > >> migration dump using it. > >> > >> With this, you can now fully examine all glorious details that go over the > >> wire when virtual machine state gets dumped, such as during live migration. > >> > >> We discussed the approach taken here during KVM Forum 2013. Originally, my idea > >> was to include a special device that contains the JSON data which can be enabled > >> on demand. Anthony suggested however to just always include the description data > >> after the end marker which I think is a great idea. > >> > >> Example decoded migration: http://csgraf.de/mig/mig.txt > >> Example migration description: http://csgraf.de/mig/mig.desc.txt > >> Presentation: https://www.youtube.com/watch?v=iq1x40Qsrew > >> Slides: https://www.dropbox.com/s/otp2pk2n3g087zp/Live%20Migration.pdf > > > > Nice to finally see this! > > > > I guess you have a v4 coming soon? > > Yeah, I was just waiting on a bit more review :) I have no problem with the series :-) In fact I forgot to note - the vmstate checker can use the json output introduced here :) Amit