periodically save current time to time-of-day hardware

[Andriy Gapon]

on 29/03/2010 17:44 John Baldwin said the following:
> On Sunday 28 March 2010 7:45:25 am Dag-Erling Smørgrav wrote:
>> Peter Jeremy <peterjeremy at acm.org> writes:
>>> A new kthread which sleeps on channel "update_rtc".  When woken, it
>>> checks to see if it's within (say) 50msec of a second boundary and so,
>>> it does a trylock on the (new) RTC mutex.  If it grabs the mutex then
>>> it performs the update.  If it was too far from the second boundary or
>>> it fails to grab the mutex then it sleeps until the next second
>>> boundary and tries again.
>>>
>>> The existing resettodr() would then turn into a wakeup(update_rtc).
>> Sounds good to me, but if only that thread has access to the RTC, why
>> bother with a mutex?
> 
> I would dispense with the kthread and just use a callout (or have a callout 
> schedule a task for taskqueue_thread).

Guys,

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?

-- 
Andriy Gapon