Re: [PATCH] dyn-tick3 tweaks

Con Kolivas
2005-08-05T01:43:34Z

On Fri, 5 Aug 2005 10:53 am, Nick Piggin wrote:
> Con Kolivas wrote:
> > Something like this on top is cleaner and quieter. I'll add this to
> > pending changes for another version.
> >
> >
> > ------------------------------------------------------------------------
> >
> > Index: linux-2.6.13-rc5-ck2/arch/i386/kernel/timers/timer_tsc.c
> > ===================================================================
> > ---
> > linux-2.6.13-rc5-ck2.orig/arch/i386/kernel/timers/timer_tsc.c 2005-08-03
> > 11:29:29.000000000 +1000 +++
> > linux-2.6.13-rc5-ck2/arch/i386/kernel/timers/timer_tsc.c 2005-08-05
> > 10:22:25.000000000 +1000 @@ -167,10 +167,20 @@ static void
> > delay_tsc(unsigned long loop
> > } while ((now-bclock) < loops);
> > }
> >
> > +/* update the monotonic base value */
> > +static inline void update_monotonic_base(unsigned long long last_offset)
> > +{
> > + unsigned long long this_offset;
> > +
> > + this_offset = ((unsigned long long)last_tsc_high << 32) | last_tsc_low;
> > + monotonic_base += cycles_2_ns(this_offset - last_offset);
> > + write_sequnlock(&monotonic_lock);
> > +}
> > +
>
> All else being equal, it is much better if you unlock in the
> same function that takes the lock. For readability.
>
> It looks like you should be able to leave all the flow control
> and locking the same, and use update_monotonic_base() to
> do the actual update?

Good advice, thanks. Will respin.

Cheers,
Con