From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dor Laor Subject: Re: Windows 2003: ping -n doesn't wait Date: Wed, 21 Jan 2009 16:05:45 +0200 Message-ID: <49772BB9.6010102@redhat.com> References: Reply-To: dlaor@redhat.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, Marcelo Tosatti To: Sven Rudolph Return-path: Received: from mx2.redhat.com ([66.187.237.31]:38920 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752527AbZAUOFc (ORCPT ); Wed, 21 Jan 2009 09:05:32 -0500 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: Sven Rudolph wrote: > Hello, > > first the facts required by bug reporting guidelines: > > - two Quad-Core AMD Opteron(tm) Processors 2352 > - kvm-83 (both kernel and userland) > - Host kernel: 2.6.28.1, x86_64 > - guest: > - 4 CPUs assigned to this guest (-smp 4) > - Microsoft Windows 2003 Server, Standard Edition, Service Pack 2 > - qemu command line: > qemu-system-x86_64 -m 4096 -boot c -hda hda.dat -smp 4 \ > -net nic,macaddr=00:50:56:24:0b:37,model=virtio \ > -net tap,ifname=vm03,script=no,downscript=no > > The problem: When running "ping -n 3 localhost" on the guest it should > wait one second between each ping request and the time needed should > be non-negative and below 10 ms. Instead, ping does not actually wait > between sending the packets, and the time for the requests ist often > displayed to be too large or negative. Simple examples: > > [WinNT] ping -n 3 localhost > > Ping wird ausgefhrt fr localhost [127.0.0.1] mit 32 Bytes Daten: > > Antwort von 127.0.0.1: Bytes=32 Zeit=-465ms TTL=128 > Antwort von 127.0.0.1: Bytes=32 Zeit=-613ms TTL=128 > Antwort von 127.0.0.1: Bytes=32 Zeit=-465ms TTL=128 > > Ping-Statistik fr 127.0.0.1: > Pakete: Gesendet = 3, Empfangen = 3, Verloren = 0 (0% Verlust), > Ca. Zeitangaben in Millisek.: > Minimum = -613ms, Maximum = -465ms, Mittelwert = 1431655251ms > > [WinNT] ping -n 3 localhost > > Ping wird ausgefhrt fr localhost [127.0.0.1] mit 32 Bytes Daten: > > Antwort von 127.0.0.1: Bytes=32 Zeit=14699ms TTL=128 > Antwort von 127.0.0.1: Bytes=32 Zeit=14699ms TTL=128 > Antwort von 127.0.0.1: Bytes=32 Zeit=14699ms TTL=128 > > Ping-Statistik fr 127.0.0.1: > Pakete: Gesendet = 3, Empfangen = 3, Verloren = 0 (0% Verlust), > Ca. Zeitangaben in Millisek.: > Minimum = 14699ms, Maximum = 14699ms, Mittelwert = 14699ms > > This makes the problem disappear: > - -smp 1 > > And these do not make the problem disappear: > - -no-kvm-irqchip > - -no-kvm-pit > > Testing with -no-kvm makes no sense because -no-kvm only works with > one CPU (and using "-smp 4 -no-kvm" causes an immediate segfault). > > In addition I tried the -clock options. hpet and rtc didn't run > ("could not initialize alarm timer"); and dynticks and unix didn't > make the problem disappear. > > Ideas, hints, or requests for more info? > It's an unsync tsc issue. I have it reproduced also over latest head. Marcelo, can you comment on it? > Sven > > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >