[PATCH] ppc32: add CONFIG_HZ
marcelo.tosatti at cyclades.com
Thu Sep 8 11:04:28 EST 2005
On Fri, Aug 26, 2005 at 02:31:44PM -0700, Tom Rini wrote:
> On Fri, Aug 26, 2005 at 04:13:04PM -0400, Dan Malek wrote:
> > On Aug 26, 2005, at 3:15 PM, Kumar Gala wrote:
> > >While ppc32 has the CONFIG_HZ Kconfig option, it wasnt actually being
> > >used. Connect it up and set all platforms to 250Hz. This pretty much
> > >mimics the ppc64 patch from Anton Blanchard.
> > Why do we keep cranking up this clock frequency? Do we really need
> > it running that fast? Is it time for someone with RTOS experience to
> > implement a real scheduled clock queue in Linux instead of just
> > wasting interrupts decrementing a counter waiting for the next
> > event to expire? :-) If the user "ticks" are still 100 Hz, don't we
> > need
> > something that is an integer multiple of that for at least an attempt
> > at getting it close to what a user would request?
> So 250 is supposed to be the best choice of power vs latency and such.
> But hey, there's nothing stopping us from setting all of the embedded
> configs back down to 100 :)
Kumar, can you please change your patch to make CONFIG_8xx use 100Hz?
There was a significant performance increase from doing that (vs 1000Hz)
on a 48Mhz 8xx with small cache.
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