From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:52621) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QKTXB-000094-V5 for qemu-devel@nongnu.org; Thu, 12 May 2011 06:54:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QKTX7-0001Vd-4U for qemu-devel@nongnu.org; Thu, 12 May 2011 06:54:21 -0400 Received: from mail.valinux.co.jp ([210.128.90.3]:34459) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QKTX6-0001V2-L4 for qemu-devel@nongnu.org; Thu, 12 May 2011 06:54:17 -0400 Date: Thu, 12 May 2011 19:54:11 +0900 From: Isaku Yamahata Message-ID: <20110512105411.GH14575@valinux.co.jp> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Qemu-devel] [PATCH] Add warmup phase for live migration of large memory apps List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Juan Quintela Cc: Stefan Hajnoczi , ohmura.kei@lab.ntt.co.jp, tamura.yoshiaki@gmail.com, "Shribman, Aidan" , "qemu-devel@nongnu.org" On Thu, May 12, 2011 at 12:39:22PM +0200, Juan Quintela wrote: > "Shribman, Aidan" wrote: > >> On Wed, May 11, 2011 at 8:58 AM, Shribman, Aidan > >> wrote: > >> > From: Aidan Shribman > >> > > >> > [PATCH] Add warmup phase for live migration of large memory apps > >> > > >> > By invoking "migrate -w " we initiate a background > >> live-migration > >> > transferring of dirty pages continuously until invocation > >> of "migrate_end" > >> > which attempts to complete the live migration operation. > >> > >> What is the purpose of this patch? How and when do I use it? > >> > > > > The warmup patch adds none-converging background update of guest > > memory during live-migration such that on request of live-migration > > completion (via "migrate_end" command) we get much faster > > response. This is especially needed when running a payload of large > > enterprise applications which have high memory demands. > > We should integrate this with Kemari (Kemari is doing something like > this, just that it has more requirements). Isaku, do you have any comments? Yochi and Kei are familiar with Kemari. Not me. Cced to them. > > BTW, what loads have you tested for this? > > if I setup an image with 1GB RAM and a DVD iso image, and do in the > guest: > > while true; do find /media/cdrom -type f | xargs md5sum; done > > Migration never converges with current code (if you use more than 1GB > memory, then all the DVD will be cached inside). > > So, I see this only useful for guests that are almost idle, and on that > case, migration speed is not the bigger of your problems, no? > > Later, Juan. > -- yamahata