Re: [Xen-devel] S3 sleep in dom0 breaks dom0<->domU wallclock synchronization

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 05/07/2010 20:18, "Jeremy Fitzhardinge" <jeremy@xxxxxxxx> wrote:

> So the problem is that dom0 does the S3 suspend/resume, and presumably
> its wallclock time is updated properly via Linux's normal mechanisms.
> But the S3 suspend/resume is unnoticed by all the domUs, so they don't
> know that an enormous amount of time has passed in an instant?  Does
> that affect all the guest clocks, or just wallclock?

Um, just wallclock I think?

> How does Xen deal with the S3 suspend/resume?  Does the system clock
> just keep ticking as usual (so the whole suspended time appears to be
> sub-nanosecond), but the wallclock offset gets updated?

This.

 -- Keir

> Or does it try
> to workout how long the suspended time was and adjusts the system time
> accordingly?  That would allow guest timekeeping to compensate for the
> suspended time, assuming they can deal with large forward leaps.



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