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SubjectRe: [Patch] Fix the possibility of insane return value of hpet_calibrate() against SMI.

Sorry for late response.

> Yasunori Goto wrote:
> > > I've no sense of feel for how long each calibration run would take.
> > > Would doing it 5 times show up as a significant increase in the boot
> > > time for those that care about boot time being as quick as possible?
> >
> > Hmm. The loop times is trade off against reliable value....
> > Though SMI is rare interruption, I don't know how frequent
> > hypervisor's switch is.
>
> Could you, just for testing, run the calibration five thousand times or
> so instead of five times, and count how often you get insane values?
> (And how much delay does such an SMI add?)

I tried 50000 times. But insane value was nothing.
I think SMI is very rare.

> > Each calibration of this has 1 milli second.
> > Do you think 5 msec is too long?
>
> This shouldn't matter when booting. Anyway, I think it's possible to
> increase TICK_CALIBRATE without losing too much accuracy.

Hmm. If the person who is trying to reduce boot time for fastboot dislikes this impact,
then I'll try Vojtech-san's way.


Thanks.
--
Yasunori Goto




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