Subject: Re: get_cycles()

From: [email-masked] (Tony Breeds)
Date: Mon, 28 Apr 2008 14:38:05 +1000

On Sun, Apr 27, 2008 at 03:35:54AM -0700, Kevin Diggs wrote:

> I'm working on a cpufreq driver for the 750GX so I don't think I have to 
> worry about being to platform specific.
> 
> Would a compile time configuration be a good idea (hrtimer or 
> get_cycles() assisted timing)?

Save yourself the pain, and use the hrtimers infrastructure.
 
> In the 2.4 code I just used a timer 2 ticks in the future to be certain 
> I did not go under the 100 us PLL lock delay. I was trying to see if I 
> could cut the latency down.
> 
> What about using OF? Isn't there a timebase property for the cpus?

Sure, If you really don't want to use the infrastructure that's there
feel free to duplicate portions of arch/powerpc/kernel/time.c and
kernel/time/* into your cpufreq driver.

Yours Tony

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