From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:48551) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RxaqN-0004G7-5b for qemu-devel@nongnu.org; Wed, 15 Feb 2012 04:08:12 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RxaqH-0002BV-HK for qemu-devel@nongnu.org; Wed, 15 Feb 2012 04:08:07 -0500 Received: from goliath.siemens.de ([192.35.17.28]:21320) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RxaqH-0002BH-4f for qemu-devel@nongnu.org; Wed, 15 Feb 2012 04:08:01 -0500 Message-ID: <4F3B75E3.30005@siemens.com> Date: Wed, 15 Feb 2012 10:07:47 +0100 From: Jan Kiszka MIME-Version: 1.0 References: <4F333AAA.1070601@cn.fujitsu.com> <4F333D77.8040104@cn.fujitsu.com> <4F3AA24E.5070201@siemens.com> <4F3AA796.90900@siemens.com> <4F3B2AC8.5030702@cn.fujitsu.com> In-Reply-To: <4F3B2AC8.5030702@cn.fujitsu.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC][PATCH 10/16 v6] run dump at the background List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Wen Congyang Cc: Eric Blake , HATAYAMA Daisuke , Dave Anderson , qemu-devel , Luiz Capitulino On 2012-02-15 04:47, Wen Congyang wrote: > At 02/15/2012 02:27 AM, Jan Kiszka Wrote: >> On 2012-02-14 19:05, Jan Kiszka wrote: >>> On 2012-02-09 04:28, Wen Congyang wrote: >>>> The new monitor command dump may take long time to finish. So we need run it >>>> at the background. >>> >>> How does it work? Like live migration, i.e. you retransmit (overwrite) >>> already written but then dirtied pages? Hmm... no. >>> >>> What does background mean then? What is the use case? What if the user >>> decides to resume the vm? >> >> OK, that is addressed in patch 15! I would suggest merging it into this >> patch. It makes sense to handle that case gracefully right from the >> beginning. > > OK, I will merge it. > >> >> OK, now I have some other question: What is the point of rate-limiting >> the dump? The guest is not running, thus not competing for bandwidth. > > I use bandwidth to try to control the writing speed. If we write the vmcore > to disk in a high speed, it may affect some other appilications which use > the same disk too. Just like the guest of that particular VM can do. I don't think we need this level of control here, it will be provided (if required) at a different level, affecting the whole QEMU process. Removing the vmcore bandwidth control will simplify code and user interface. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux