Re: [PATCH] Time precision, adjtime(x) vs. gettimeofday

[john stultz]

On Wed, 2003-10-08 at 11:25, Stephen Hemminger wrote:
> On Wed, 08 Oct 2003 15:32:31 +0200
> Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> wrote:
> > 
> > That means that if, for example, adjtimex was called with a factor
> > that is trying to slow you down a bit, and you call gettimeofday
> > right before the end of a jiffy period, you may calculate an offset
> > based on the HW timer that is actually higher than what will be
> > really added to xtime on the next interrupt.
[snip]
> The following will prevent adjtime from causing time regression.
> It delays starting the adjtime mechanism for one tick, and 
> keeps gettimeofday inside the window.

Hmm. Looks good to me. If we're losing ticks, it would make time
stair-step somewhat, but it doesn't seem to affect the actual time
accumulation. 

thanks
-john



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