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 10:28:33 +0100 Message-ID: <49B4E141.3000306@wpkg.org> References: <49B29705.6000904@wpkg.org> <49B4DEE4.9060705@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]:47893 "EHLO mx03.syneticon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752339AbZCIJ2j (ORCPT ); Mon, 9 Mar 2009 05:28:39 -0400 Received: from localhost (filter1.syneticon.net [192.168.113.83]) by mx03.syneticon.net (Postfix) with ESMTP id 7792A35E24 for ; Mon, 9 Mar 2009 10:28:36 +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 TIFHlFRH2msH for ; Mon, 9 Mar 2009 10:28:34 +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 10:28:34 +0100 (CET) In-Reply-To: <49B4DEE4.9060705@wpkg.org> Sender: kvm-owner@vger.kernel.org List-ID: Tomasz Chmielewski schrieb: > 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): This is also pretty interesting: # ping -c 10 PING 192.168.4.4 (192.168.4.4) 56(84) bytes of data. 64 bytes from 192.168.4.4: icmp_seq=1 ttl=64 time=1.25 ms 64 bytes from 192.168.4.4: icmp_seq=2 ttl=64 time=1.58 ms 64 bytes from 192.168.4.4: icmp_seq=3 ttl=64 time=3.53 ms 64 bytes from 192.168.4.4: icmp_seq=4 ttl=64 time=1.43 ms 64 bytes from 192.168.4.4: icmp_seq=5 ttl=64 time=3.89 ms 64 bytes from 192.168.4.4: icmp_seq=6 ttl=64 time=3.43 ms 64 bytes from 192.168.4.4: icmp_seq=7 ttl=64 time=1.03 ms 64 bytes from 192.168.4.4: icmp_seq=8 ttl=64 time=1.36 ms 64 bytes from 192.168.4.4: icmp_seq=9 ttl=64 time=1.28 ms 64 bytes from 192.168.4.4: icmp_seq=10 ttl=64 time=1.78 ms --- 192.168.4.4 ping statistics --- 10 packets transmitted, 10 received, 0% packet loss, time 9091ms rtt min/avg/max/mdev = 1.031/2.059/3.894/1.045 ms How probable it is so many pings returned with exactly 1000 ms? # ping -c 10 PING 192.168.4.5 (192.168.4.5) 56(84) bytes of data. 64 bytes from 192.168.4.5: icmp_seq=1 ttl=64 time=1009 ms 64 bytes from 192.168.4.5: icmp_seq=2 ttl=64 time=9.61 ms 64 bytes from 192.168.4.5: icmp_seq=3 ttl=64 time=1000 ms 64 bytes from 192.168.4.5: icmp_seq=4 ttl=64 time=1000 ms 64 bytes from 192.168.4.5: icmp_seq=5 ttl=64 time=1000 ms 64 bytes from 192.168.4.5: icmp_seq=6 ttl=64 time=992 ms 64 bytes from 192.168.4.5: icmp_seq=7 ttl=64 time=1000 ms 64 bytes from 192.168.4.5: icmp_seq=8 ttl=64 time=1001 ms 64 bytes from 192.168.4.5: icmp_seq=9 ttl=64 time=1000 ms 64 bytes from 192.168.4.5: icmp_seq=10 ttl=64 time=998 ms --- 192.168.4.5 ping statistics --- 10 packets transmitted, 10 received, 0% packet loss, time 10025ms rtt min/avg/max/mdev = 9.610/901.198/1009.161/297.222 ms, pipe 2 This one is with "dd if=/dev/vda of=/dev/null" running on the affected guest: # ping -c 10 PING 192.168.4.5 (192.168.4.5) 56(84) bytes of data. 64 bytes from 192.168.4.5: icmp_seq=1 ttl=64 time=29.4 ms 64 bytes from 192.168.4.5: icmp_seq=2 ttl=64 time=4.56 ms 64 bytes from 192.168.4.5: icmp_seq=3 ttl=64 time=4.05 ms 64 bytes from 192.168.4.5: icmp_seq=4 ttl=64 time=4.20 ms 64 bytes from 192.168.4.5: icmp_seq=5 ttl=64 time=3.82 ms 64 bytes from 192.168.4.5: icmp_seq=6 ttl=64 time=2.47 ms 64 bytes from 192.168.4.5: icmp_seq=7 ttl=64 time=2.16 ms 64 bytes from 192.168.4.5: icmp_seq=8 ttl=64 time=3.89 ms 64 bytes from 192.168.4.5: icmp_seq=9 ttl=64 time=5.98 ms 64 bytes from 192.168.4.5: icmp_seq=10 ttl=64 time=9.16 ms --- 192.168.4.5 ping statistics --- 10 packets transmitted, 10 received, 0% packet loss, time 9107ms rtt min/avg/max/mdev = 2.169/6.978/29.439/7.714 ms -- Tomasz Chmielewski http://wpkg.org