Re: [RFC][patch 00/12] clocksource / timekeeping rework V2

Martin Schwidefsky
2009-07-29T16:51:20Z

On Wed, 29 Jul 2009 09:10:31 -0600
dwalker@fifo99.com wrote:

> On Wed, 2009-07-29 at 15:41 +0200, Martin Schwidefsky wrote:
> > There is still more room for improvement. Some sore points are:
> >
> > 1) The cycle_last value still is in the struct clocksource. It should
> > be in the struct timekeeper but the check against cycles_last in
> > the
> > read function of the TSC clock source makes it hard.
> > 2) read_persistent_clock returns seconds. With a really good initial
> > time source this is not very precise. read_persistent_clock should
> > return a struct timespec.
> > 3) xtime, raw_time, total_sleep_time, timekeeping_suspended, jiffies,
> > the ntp state and probably a few other values may be better located
> > in the struct timekeeper as well.
>
>
> You could also consolidate the clocksource_unregister() path and the
> clocksource_change_rating(0) path , both are basically doing the same
> thing.. Neither one is heavily used..

I'm not quite sure I got this. If I look at the code:

/**
* clocksource_change_rating - Change the rating of a registered clocksource
*/
void clocksource_change_rating(struct clocksource *cs, int rating)
{
mutex_lock(&clocksource_mutex);
cs->rating = rating;
clocksource_select();
mutex_unlock(&clocksource_mutex);
}
EXPORT_SYMBOL(clocksource_change_rating);

/**
* clocksource_unregister - remove a registered clocksource
*/
void clocksource_unregister(struct clocksource *cs)
{
mutex_lock(&clocksource_mutex);
clocksource_dequeue_watchdog(cs);
list_del(&cs->list);
clocksource_select();
mutex_unlock(&clocksource_mutex);
}
EXPORT_SYMBOL(clocksource_unregister);

the two functions do different things. What exactly is the idea you've
got in mind?

--
blue skies,
Martin.

"Reality continues to ruin my life." - Calvin.