Re: [patch v5 06/15] sched: log the cpu utilization at rq

Alex Shi
2013-02-20T14:37:02Z

On 02/20/2013 09:34 PM, Peter Zijlstra wrote:
> On Wed, 2013-02-20 at 17:39 +0530, Preeti U Murthy wrote:
>> Hi,
>>
>>>> /*
>>>> * This is the main, per-CPU runqueue data structure.
>>>> *
>>>> @@ -481,6 +484,7 @@ struct rq {
>>>> #endif
>>>>
>>>> struct sched_avg avg;
>>>> + unsigned int util;
>>>> };
>>>>
>>>> static inline int cpu_of(struct rq *rq)
>>>
>>> You don't actually compute the rq utilization, you only compute the
>>> utilization as per the fair class, so if there's significant RT activity
>>> it'll think the cpu is under-utilized, whihc I think will result in the
>>> wrong thing.
>>
>> Correct me if I am wrong,but isn't the current load balancer also
>> disregarding the real time tasks to calculate the domain/group/cpu level
>> load too?
>
> Nope, the rt utilization affects the cpu_power, thereby correcting the
> weight stuff.

The balance policy use group capacity, that implicated using cpu power,
but seems capacity is a very rough data.
>
>

--
Thanks
Alex