Re: bltk-game regressions on snb laptop

[Alex Shi <alex.shi@intel.com>]

On 04/18/2013 12:26 PM, Viresh Kumar wrote:
> On 18 April 2013 06:18, Alex Shi <alex.shi@intel.com> wrote:
>> On 04/18/2013 12:46 AM, Viresh Kumar wrote:
>>> On 16 April 2013 12:44, Alex Shi <alex.shi@intel.com> wrote:
> 
>> Hi, Viresh, correct me if I am wrong. :)
>>
>> the affected_cpus value changed from 3.9-rc1, then we get the good performance,
>> and dropped after this commit. I have reverted this patch, then the performance recovered.
> 
> 
> What's the fps value you got with v3.8? Current values should be
> similar to that.

Yes. current value is similar to 3.8: 18fps, compare to 3.9-rc1, that is
also bad.
I mean the good performance started from 3.9-rc1 kernel.

> About your system: Can you give output of cpufreq-info for v3.8 and
> v3.9-latestrc?
> Your cpus share a clock line or not?

Yes our cpu shares a clock line. So the cpufreq-info is same. SNB CPU
p-state is per cpu package, and hardware will coordinate the software
asking, then decide which cpufreq should be.
> 
>> this patch remove the unconditionally related_cpus set:
>> @@ -730,7 +730,6 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
>>             policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {
>>                 cpumask_copy(policy->cpus, perf->shared_cpu_map);
>>         }
>> -       cpumask_copy(policy->related_cpus, perf->shared_cpu_map);
> 
> Because setting related cpus now didn't had a meaning and people were
> facing regressions due to it.

I know. So, I reported this issue without asking for revert. :)
> 
>>
> 
>> Our p-state should be hardware coordinate, so affected_cpus is right on your patch.
> 
> Didn't get that.. Your cpus share clock line? If so, they should be set in
> policy->cpus by your driver and same would be reflected in related_cpus
> by cpufreq core.

That's sth I am also confused. Yes, that cpu share a clock line. But
Arjan and Len both said affected_cpus should only include the cpu self,
because cpu will do hardware coordination for them.
> 


-- 
Thanks Alex