[lkml]   [2007]   [Feb]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH 1/3] Introducing cpuidle: core cpuidle infrastructure
On Mon, Feb 12, 2007 at 10:39:25AM -0800, Venkatesh Pallipadi wrote:
> Introducing 'cpuidle', a new CPU power management infrastructure to manage
> idle CPUs in a clean and efficient manner.
> cpuidle separates out the drivers that can provide support for multiple types
> of idle states and policy governors that decide on what idle state to use
> at run time.
> A cpuidle driver can support multiple idle states based on parameters like
> varying power consumption, wakeup latency, etc (ACPI C-states for example).
> A cpuidle governor can be usage model specific (laptop, server,
> laptop on battery etc).
> Main advantage of the infrastructure being, it allows independent development
> of drivers and governors and allows for better CPU power management.
> A huge thanks to Adam Belay and Shaohua Li who were part of this mini-project
> since its beginning and are greatly responsible for this patchset.

interesting. Though I wonder about giving admins _more_ knobs to twiddle.
It took cpufreq a long time to settle down in this area, and typically
'ondemand' was the answer in the end for 99.9% of people. I question the usefulness
for the whole multiple governors interface, because in the case of cpuidle
there shouldn't be any real trade-off between one algorithm and another afaics?
So why can't we just have one, that just 'does the right thing' ?
The only differentiator that I can think of would be latency, but that seems
to be a) covered in a different tunable, and b) probably wouldn't affect
most people enough where it matters.

I'll do a proper code review later, but one thing stuck out like a sore
thumb on a quick skim..

> +EXPORT_SYMBOL_GPL(current_driver);

That's a horribly generic name for an exported global.

current_cpuidle_driver maybe?

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2007-02-13 02:27    [W:0.122 / U:0.776 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site