Marcelo Tosatti <mtosatti@xxxxxxxxxx> writes: > 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. Adding /usepmtimer in boot.ini solves the problem, see http://support.microsoft.com/kb/938448/en-us : To resolve this problem, configure Windows Server 2003 to use the PM_TIMER setting instead of the time-stamp counter. To do this, add the /usepmtimer parameter to the Boot.ini file, and then restart the server. Note The /usepmtimer parameter is automatically added to the Boot.ini file when you install the latest AMD PowerNow! Technology driver from AMD. The updated driver itself does not resolve this problem. However, the installation process makes the necessary changes to the Boot.ini file to resolve this problem. This might solve other spurious problems (stalled logins; loss of SMB file service connections, scratched Windows profiles) too; I will test this in the next days. Sven -- 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
