Re: recommended clock source

Antoine Martin
2009-08-03T08:12:04Z

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Hi,

Dor Laor wrote:
> On 08/03/2009 04:52 AM, Kent Tong wrote:
>> Hi,
>>
>> It seems to be an unsettled issue, but, would any kind soul suggest
>> the current
>> best practice for setting the clock in Ubuntu Linux and Windows guests?
>
> For Linux the best source clock is the kvm pv clock (exist from 2.6.27
> and above).
# qemu-system-x86_64 -clock ?
Available alarm timers, in order of precedence:
dynticks
hpet
rtc
unix

I see no "pv clock"...
Which one should I use then?
Did I miss a ./configure or .config option?

Cheers
Antoine

>
> For windows, standard acpi HAL uses the rtc clock by default. As long as
> you use the -rtc-td-hack it won't drift.
>
> When the tsc is not stable on the host or the host cpu might get into
> deep sleep state (c2), you better use another source clock in the guest
> - for windows it should be the pmtimer (using the boot.ini).
>
>>
>> Thanks!
>>
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