From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomasz Chmielewski Subject: Re: strange guest slowness after some time Date: Mon, 09 Mar 2009 10:18:28 +0100 Message-ID: <49B4DEE4.9060705@wpkg.org> References: <49B29705.6000904@wpkg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit To: "kvm@vger.kernel.org" Return-path: Received: from mx03.syneticon.net ([78.111.66.105]:34873 "EHLO mx03.syneticon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752380AbZCIJSi (ORCPT ); Mon, 9 Mar 2009 05:18:38 -0400 Received: from localhost (filter1.syneticon.net [192.168.113.83]) by mx03.syneticon.net (Postfix) with ESMTP id 4DC8535E24 for ; Mon, 9 Mar 2009 10:18:33 +0100 (CET) Received: from mx03.syneticon.net ([192.168.113.84]) by localhost (mx03.syneticon.net [192.168.113.83]) (amavisd-new, port 10025) with ESMTP id Y6P4BaD71ePm for ; Mon, 9 Mar 2009 10:18:30 +0100 (CET) Received: from [192.168.10.145] (koln-4db4063e.pool.einsundeins.de [77.180.6.62]) by mx03.syneticon.net (Postfix) with ESMTPSA for ; Mon, 9 Mar 2009 10:18:30 +0100 (CET) In-Reply-To: <49B29705.6000904@wpkg.org> Sender: kvm-owner@vger.kernel.org List-ID: Tomasz Chmielewski schrieb: > The host is running kvm-83. > Affected guests are running 2.6.27.14 kernels and use virtio drivers. > The problem happens only _sometimes_. Out of 9 guests I have running on > this host, I saw this problem only on 3 guests. I never saw this > happening on more than one guest at a time. > All three have 512 MB memory assigned, other guests have less memory. I upgraded ~2 days ago to kvm-84 and the same just happened for a guest with 256 MB memory. Note how _time_ is different (similar timings are to other unaffected guests): # ping -f -c 10000 10000 packets transmitted, 10000 received, 0% packet loss, time 12313ms rtt min/avg/max/mdev = 0.432/1.164/96.163/1.934 ms, pipe 7, ipg/ewma 1.231/1.111 ms # ping -f -c 10000 10000 packets transmitted, 10000 received, 0% packet loss, time 135625ms rtt min/avg/max/mdev = 0.807/14.228/55.569/5.779 ms, pipe 4, ipg/ewma 13.563/8.601 ms Running "dd if=/dev/vda of=/dev/null" on the affected guest reduces that a bit: # ping -f -c 10000 10000 packets transmitted, 10000 received, 0% packet loss, time 50469ms rtt min/avg/max/mdev = 0.616/4.881/54.357/3.847 ms, pipe 5, ipg/ewma 5.047/7.783 ms Anyone? Is it a known bug? -- Tomasz Chmielewski http://wpkg.org