From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:42839) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TRKmT-0007DO-WB for qemu-devel@nongnu.org; Thu, 25 Oct 2012 06:35:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TRKmQ-00036j-1R for qemu-devel@nongnu.org; Thu, 25 Oct 2012 06:35:17 -0400 Received: from mail.profihost.ag ([85.158.179.208]:56365) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TRKmP-00036Y-OW for qemu-devel@nongnu.org; Thu, 25 Oct 2012 06:35:13 -0400 Message-ID: <508915DE.5080509@profihost.ag> Date: Thu, 25 Oct 2012 12:35:10 +0200 From: Stefan Priebe - Profihost AG MIME-Version: 1.0 References: <5088F46D.6080605@profihost.ag> <508909F4.8020100@redhat.com> In-Reply-To: <508909F4.8020100@redhat.com> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] slow xbzrle List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Orit Wasserman Cc: qemu-devel Am 25.10.2012 11:44, schrieb Orit Wasserman: >> Is this known or is something wrong? > My guess this workload migrates fine without XBZRLE so it is not the speed or downtime :). > it could be that the cache size is too small resulting with a lot of cache misses which means > XBZRLE makes things worse and just uses CPU to maintain the cache. > Other option is that this workload changes the pages too much which can result with a lot of over flows > which result in XBZRLE to waste CPU scanning the pages. > As this is idle mysql my guess it the first scenario. > > Can you send the cache size, cache miss and overflow (from 'info migrate')? Example got from a log file (it's the info from info migrate just in another format): migration xbzrle cachesize: 1073741824 transferred 0 pages 0 cachemiss 1315374 overflow 0 Stefan