On 01/31/2013 02:58 PM, Namhyung Kim wrote:
> On Thu, 31 Jan 2013 14:39:20 +0800, Michael Wang wrote:
>> On 01/31/2013 01:16 PM, Namhyung Kim wrote:
>>> Anyway, I have an idea with this in mind. It's like adding a new "idle
>>> load" to each idle cpu rather than special casing the idle cpus like
>>> above. IOW an idle cpu will get very small load weight depends on how
>>> deep it's slept so that it can be compared to other cpus in a same way
>>> but we can find prefered (lowest load) cpu among the idle cpus.
>>>
>>> The simple way I can think of is adding idle_level to a rq load in
>>> weighted_cpuload():
>>>
>>> static unsigned long weighted_cpuload(const int cpu)
>>> {
>>> return cpu_rq(cpu)->load.weight + cpuidle_get_state(cpu);
>>> }
>>
>> Hmm... then we don't need changes in find_idlest_cpu(), just compare the
>> load as before, but it works only when the appendix state value is
>> smaller than the lowest load of one task, which is 15 currently, I'm not
>> sure whether we have the promise...
>
> You said about a nice 19 process, right? But I found that SCHED_IDLE
> task will have weight of 3. :(
>
> #define WEIGHT_IDLEPRIO 3
I missed that policy :)
>
>
> But AFAIK the number of states in cpuidle is usually less than 10 so maybe
> we can change the weight then, but there's no promise...
And I just got another case we should take care:
group 0 cpu 0 cpu 1
power index 8 power index 8
group 1 cpu 2 cpu 3
power index 0 load 15
so load of group 0 is 16 and group 1 is 15, but group 0 is better...
Regards,
Michael Wang
>
> Thanks,
> Namhyung
>
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