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Re: [Xen-devel] Re: Clock Running Fast on Win7 DomU

Hi Tom,

At 09:18 -0400 on 16 Jun (1308215917), Tom Goetz wrote:
> We've tracked this down further an it seems to be an issue with the virtual 
> HPET. Some difference between 3.4.2 and 4.0.1 results in Win7 clock running 
> fast. The lower the programmed frequency the more accurate the Win7 clock is.
> HPET frequency vs time for Win7 clock to tick off 60s:
> 1ms     60s
> 10ms   50s
> 15ms   46s

Have you been able to reproduce this on 4.1 or 4.2-unstable?  The Win7
clock seems to be running at the right speed for me on unstable, just by
booting win7 (sp1, 64-bit) and bringing up the desktop clock.  Or do I
need to do something in particular to change the granularity to 1ms?


> In Win7 the 'rate adjustment' column of the HalpHpetClockTable is zero for 
> all frequencies. Our current working theory is that an issue at startup is 
> causing the error calibration to fail or not happen resulting in larger 
> errors at larger frequencies.

Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Principal Software Engineer, Xen Platform Team
Citrix Systems UK Ltd.  (Company #02937203, SL9 0BG)

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