On Tue, 4 Mar 2008 11:01:28 -0800
"Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com> wrote:

quoted text
> >
> >(On that subject, does anyone except Adam understand that 
> >algorithm? Some comments wouldn't hurt...)
> 
> Prediction is based on cumulative time till "non expected wakeup". So,
> prediction will come into play only when there are very short wakeups
> due to "unexpected wakeups".
> 

Ah, so the measured_us and elapsed_us are trying to keep track of time between non-timer wakeups?

quoted text
> >So for now, I'm back to thinking that measuring the interval 
> >between deep sleeps is the better approach. I could use some 
> >ideas for a good clock source though. I haven't dug much 
> >deeper than jiffies when it comes to kernel timekeeping.
> 
> I think best solution is to use get_last_residency that is already
> there. If the last residency or expected_us is very low, you can avoid
> deep idle states. That way you don't have to depend on jiffies being
> updated at the time you are checking it.
> 

I tried using predicted_us and last_measured_us, and those didn't work (see the #if 0 code in my last patch). And since cpuidle_get_last_residency() is part of predicted_us, I don't think it is reporting useful values.

Rgds
-- 
     -- Pierre Ossman

  Linux kernel, MMC maintainer        http://www.kernel.org
  PulseAudio, core developer          http://pulseaudio.org
  rdesktop, core developer          http://www.rdesktop.org
--
unsubscribe notice
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/