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Date: Tue, 06 Apr 2010 15:47:37 +0300
From: Andriy Gapon <avg@freebsd.org>
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Subject: Re: periodically save current time to time-of-day hardware
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on 30/03/2010 19:43 Andriy Gapon said the following:
> 
> do you think that periodic saving of system clock to hardware and making resettodr
> asynchronous are dependent issues?  Or are they orthogonal and can be implemented
> independently?

A new version of the patch:
http://people.freebsd.org/~avg/periodic_resettodr.diff

Some notes:
- this patch doesn't implement any resettodr enhancements proposed earlier: making
it non-blocking/asynchronous and saving time closer to seconds boundary;
- the patch adds code for saving time on shutdown, adds logic for checking ntp
synchronization status and for dynamically stoping/(re-)starting the callout via
period sysctl;
- the patch consists of two pieces: the first is abstracting ntp status check into
a separate function and the other is all the time saving code;
- I don't feel that kern_ntptime.c is best place for this code, I only chose it
because of ntp status checking; perhaps ntp_is_time_error needs to be made public
and the code moved to a better file; suggestion are welcome!

I also welcome any comments and suggestions on code style, identifier naming,
logic, strategy, etc.
Thank you!

P.S. it seems that machdep is not the best place for "RTC" sysctls, but I am
deferring this issue at the moment.

-- 
Andriy Gapon