Re: [linux-pm] cpuidle future and improvements

["Shilimkar, Santosh" <santosh.shilimkar@ti.com>]

On Mon, Jun 18, 2012 at 7:00 PM, a0393909 <santosh.shilimkar@ti.com> wrote:
> Daniel,
>
>
> On 06/18/2012 02:10 PM, Daniel Lezcano wrote:
>>
>>
>> Dear all,
>>
>> A few weeks ago, Peter De Schrijver proposed a patch [1] to allow per
>> cpu latencies. We had a discussion about this patchset because it
>> reverse the modifications Deepthi did some months ago [2] and we may
>> want to provide a different implementation.
>>
>> The Linaro Connect [3] event bring us the opportunity to meet people
>> involved in the power management and the cpuidle area for different SoC.
>>
>> With the Tegra3 and big.LITTLE architecture, making per cpu latencies
>> for cpuidle is vital.
>>
>> Also, the SoC vendors would like to have the ability to tune their cpu
>> latencies through the device tree.
>>
>> We agreed in the following steps:
>>
>> 1. factor out / cleanup the cpuidle code as much as possible
>> 2. better sharing of code amongst SoC idle drivers by moving common bits
>> to core code
>> 3. make the cpuidle_state structure contain only data
>> 4. add a API to register latencies per cpu
>>
>> These four steps impacts all the architecture. I began the factor out
>> code / cleanup [4] and that has been accepted upstream and I proposed
>> some modifications [5] but I had a very few answers.
>>
> Another thing which we discussed is bringing the CPU cluster/package
> notion in the core idle code. Couple idle did bring that idea to some
> extent but in can be further extended and abstracted. Atm, most of
> the work is done in back-end cpuidle drivers which can be easily
> abstracted if the "cluster idle" notion is supported in the core layer.
>
Are you considering the "cluster idle" as one of the topic ?

Regards
Santosh