Re: [ACPI] X86_PM_TIMER: /proc/cpuinfo doesn't get updated

john stultz
2004-03-18T21:09:19Z

On Thu, 2004-03-18 at 00:51, Dominik Brodowski wrote:
> On Wed, Mar 17, 2004 at 02:56:27PM -0800, Nate Lawson wrote:
> > Instead of all this gymnastics, how about:
>
> It's not so much gymnastics -- implementing different handling for cpufreq
> drivers which do not affect the TSC is easy. It's just difficult to get to
> know what drivers/CPUs are affected... and the test run you did yesterday
> helped in evaluating this. Thanks for doing so.
>
> > 1. If using Px states, state is unknown until first "set" event.
>
> Normally, when using cpufreq drivers the original state is known -- only the
> ACPI spec has this severe flaw, but there are tries for a workaround [patch
> is submitted]
>
> > 2. Implement priorities for time source selection and a generic timer API.
> > This gets around the need to get the clock rate correct to have system
> > timers work. On FreeBSD, this is /sys/kern/kern_tc.c
>
> IIRC, John Stultz intends to do a major upgrade of the timing code in 2.7.

Well, we already have time source selection in 2.6 for i386. Most other
arches have a single stable time source, so its not as critical for
them. As for 2.7, a couple of holes have been poked in my initial
design, so any major rewrite is somewhat on hold. Moving more arches to
the more generic time_interpolator interface that ia64 uses may be the
best solution, although its not as clean as I'd really like.

thanks
-john