Re: [patch] x86: scale cyc_2_nsec according to CPU frequency

[Guillaume Chazarain <guichaz@yahoo.fr>]

Le Fri, 7 Dec 2007 14:55:25 +0100,
Ingo Molnar <mingo@elte.hu> a écrit :

> Firstly, we dont need the 'offset' anymore because cpu_clock() maintains 
> offsets itself.

Yes, but a lower quality one. __update_rq_clock tries to compensate
large jumping clocks with a jiffy resolution, while my offset arranges
for a very smooth frequency transition.

I agree with keeping a single offset, but I liked the fact that with my
patch on frequency change, the clock had no jump at all.

> + *  ns += offset to avoid sched_clock jumps with cpufreq

I guess this needs to go away if I don't make my point :-(

> +	printk("CPU#%d: changed cyc2ns scale from %ld to %ld\n",
> +		cpu, prev_scale, *scale);

Pointing it out just to be sure it does not end in the final version ;-)

Thanks for cleaning up my mess ;-)

-- 
Guillaume