RE: [Xen-devel] RE: [PATCH] record max stime skew (was RE: [PATCH] strictly increasing hvm guest time)

["Dan Magenheimer" <dan.magenheimer@xxxxxxxxxx>]

> On 4/7/08 16:11, "Dan Magenheimer" <dan.magenheimer@xxxxxxxxxx> wrote:
> 
> > Oops, I misunderstood that for some reason.
> >
> > Here's a fixed version.  I also now preserve the "Platform timer is"
> > line since that can get flushed out of the dmesg buffer.

OOPS, forgot the patch!  Attached this time.

> > Any idea why the skew can get so bad?
> 
> Not really. We could check in this patch or similar and 
> perhaps collect more
> information.
> 
>  -- Keir

Well one suspicion I had was that very long hpet reads were
getting serialized, but I tried clocksource=acpi and
clocksource=pit and get similar skew range results.
In fact pit shows a max of >17000 vs hpet and acpi closer
to 11000.  (OTOH, I suppose it IS possible that this is
roughly how long it takes to read each of these platform
timers.)

Dan

maxskew4.patch
Description: Binary data

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