From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:59039) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Rxb3m-0003KS-P0 for qemu-devel@nongnu.org; Wed, 15 Feb 2012 04:22:04 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Rxb3i-0005FA-Ni for qemu-devel@nongnu.org; Wed, 15 Feb 2012 04:21:58 -0500 Received: from david.siemens.de ([192.35.17.14]:34466) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Rxb3i-0005F0-EQ for qemu-devel@nongnu.org; Wed, 15 Feb 2012 04:21:54 -0500 Message-ID: <4F3B7926.7070309@siemens.com> Date: Wed, 15 Feb 2012 10:21:42 +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> <4F3B75E3.30005@siemens.com> <4F3B7953.7020006@cn.fujitsu.com> In-Reply-To: <4F3B7953.7020006@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 10:22, Wen Congyang wrote: > At 02/15/2012 05:07 PM, Jan Kiszka Wrote: >> 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. > > OK. I will implementing it like this: > 1. write 100ms > 2. sleep 100ms(allow qemu to do the other things) > 3. goto 1 Why? Just write as fast as possible. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux