On Tue, Jan 20, 2009 at 03:53:06PM +0100, 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 Sven, Dor, Can you try to use the AMD CPU drivers for Windows? Take a look at http://forums.citrix.com/thread.jspa?threadID=93813 http://www.therightstuff.de/2007/06/05/The-Case-Of-The-Negative-Ping.aspx I don't doubt the KVM tsc syncing code for AMD is not involved, though. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
