Subject: Re: todr changes to improve clock accuracy across sleeps &
To: Perry E. Metzger <perry@piermont.com>
From: Richard Earnshaw <Richard.Earnshaw@buzzard.freeserve.co.uk>
List: tech-kern
Date: 09/07/2006 18:05:14
> It would be nice if, optionally, one could wait up to one second,
> spinning, for the RTC chip to turn over a fresh second before doing
> inittodr. Similarly, one would, optionally, wait up to one second
> before doing the resettodr -- that could be done with an interval
> timer controlled sleep since the system clock has high precision.
> I suggested making this optional (and possibly sysctlable) because
> some people won't care and will resent the one second additional
> delay.
Why not leave the setting of the system clock as is (if you aren't on
line, then clock precision to within a second is just fine); and when
shutting down, don't write the RTC if it is within (say) 1 second of the
current time. This way you've preserved essentially all the accuracy of
your RTC without stalling at any point.
R.