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

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

> > Attached is the patch.  Interestingly, on my single-socket
> > two-core recent-vintage Intel processor, this patch reports
> > a max skew of >13 usec, much higher than the values I'm
> > seeing from "xm debug-key t".  I wonder if this is due to
> > a mistake in my patch (though I don't see it) or if the
> > various stime error corrections are not converging as
> > expected, resulting in a broader stime skew between
> > processors than expected?
> 
> Perhaps this relatively large skew happens at start of day, before the
> periodic calibration has 'locked on'?

Indeed you are correct.  This updated patch now reports zero skew
as expected.

IMHO, it would be nice to put this patch into the tree as it
will be good for helping to diagnose time skew problems
such as the one just reported on the list.

Thanks,
Dan

Attachment: maxskew2.patch
Description: Binary data

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