Le 04/03/2010 16:13, Zachary Amsden a écrit :
> On 03/03/2010 11:43 PM, Gilles PIETRI wrote:
>> Hi,
>>
>> I have a host running a 2.6.32.7 kernel, and I'm using qemu-kvm 
>> 0.12.2. I have multiple guests, and one of them is running Windows XP. 
>> If I stare at the clock, I see that every now & then (~5s), it slows 
>> down a bit, and then try to cope with it. If I run some NTP 
>> synchronization software like ntpd, the offset is as high as 1s lost 
>> every 10s or so, which makes it impossible to use anything time based 
>> on the guest (audio stuff, mainly).
>>
>> I tried messing (as said on IRC) with the -rtc parameters, but to no 
>> avail. I tried the driftfix=slew option found in the --help output, 
>> but it says that driftfix is not a valid setting for rtc.. And anyway, 
>> I have no idea what this does (I'll be reading about it probably...)
>>
>> I've seen something remotely connected to this on the proxmox forum, 
>> but it was not that helpful (and proxmox runs qemu 0.11.x as it seems):
>> http://forum.proxmox.com/threads/2050-Slow-clock-time-drift-in-windows-guests?p=17962 
>>
>>
>> I remember using the -rtc-td-hack (and in fact, just read again about 
>> it here: 
>> http://forum.proxmox.com/threads/2381-Recommended-clock-source-for-KVM-guests), 
>> but it's not there anymore in 0.12.x, and I have no idea what it used 
>> to do (going on for some reading as well, when I have some time ;))
>>
>> Oh, and the guests running linux are working just fine, and have no 
>> clock issue.
>>
>> Has anyone encountered such a problem?
> 
> No, but I'd certainly like to fix it.  Can you send basic host 
> information like /proc/cpuinfo, dmesg from kernel?

It's a bi quad core Dell R710, there's a part of the /proc/cpuinfo 
below, and I attached the dmesg.

> 
> If you run the one Windows XP guest alone, does it run better or still 
> the same?

Hard to say, but I think I had the issue "from the start", when the 
guest was alone. I can't check that easily now that things are running 
however..

/proc/cpuinfo

processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 26
model name      : Intel(R) Xeon(R) CPU           E5504  @ 2.00GHz
stepping        : 5
cpu MHz         : 1994.647
cache size      : 4096 KB
physical id     : 1
siblings        : 4
core id         : 0
cpu cores       : 4
apicid          : 16
initial apicid  : 16
fpu             : yes
fpu_exception   : yes
cpuid level     : 11
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge 
mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe 
syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good 
xtopology nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 
ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt lahf_lm tpr_shadow vnmi 
flexpriority ept vpid
bogomips        : 3989.29
clflush size    : 64
cache_alignment : 64
address sizes   : 40 bits physical, 48 bits virtual
power management:

Thanks for your time,

Gilou