Re: [PATCH V2 0/3] Introduce Thermal Pressure

Thara Gopinath
2019-04-30T16:02:53Z

On 04/30/2019 11:57 AM, Thara Gopinath wrote:
> On 04/29/2019 09:29 AM, Ionela Voinescu wrote:
>> Hi Thara,
>>
>>>
>>> Hackbench: (1 group , 30000 loops, 10 runs)
>>> Result Standard Deviation
>>> (Time Secs) (% of mean)
>>>
>>> No Thermal Pressure 10.21 7.99%
>>>
>>> Instantaneous thermal pressure 10.16 5.36%
>>>
>>> Thermal Pressure Averaging
>>> using PELT fmwk 9.88 3.94%
>>>
>>> Thermal Pressure Averaging
>>> non-PELT Algo. Decay : 500 ms 9.94 4.59%
>>>
>>> Thermal Pressure Averaging
>>> non-PELT Algo. Decay : 250 ms 7.52 5.42%
>>>
>>> Thermal Pressure Averaging
>>> non-PELT Algo. Decay : 125 ms 9.87 3.94%
>>>
>>>
>>
>> I'm trying your patches on my Hikey960 and I'm getting different results
>> than the ones here.
>>
>> I'm running with the step-wise governor, enabled only on the big cores.
>> The decay period is set to 250ms.
>>
>> The result for hackbench is:
>>
>> # ./hackbench -g 1 -l 30000
>> Running in process mode with 1 groups using 40 file descriptors each (== 40 tasks)
>> Each sender will pass 30000 messages of 100 bytes
>> Time: 20.756
>>
>> During the run I see the little cores running at maximum frequency
>> (1.84GHz) while the big cores run mostly at 1.8GHz, only sometimes capped
>> at 1.42GHz. There should not be any capacity inversion.
>> The temperature is kept around 75 degrees (73 to 77 degrees).
>>
>> I don't have any kind of active cooling (no fans on the board), only a
>> heatsink on the SoC.
>>
>> But as you see my results(~20s) are very far from the 7-10s in your
>> results.
>>
>> Do you see anything wrong with this process? Can you give me more
>> details on your setup that I can use to test on my board?
>
> Hi Ionela,
>
> I used the latest mainline kernel with sched/ tip merged in for my
> testing. My hikey960 did not have any fan or heat sink during testing. I
> disabled cpu cooling for little cores in the dts files.
> Also I have to warn you that I have managed to blow up my hikey960. So I
> no longer have a functional board for past two weeks or so.
>
> I don't have my test scripts to send you, but I have some of the results
> files downloaded which I can send you in a separate email.
> I did run the test 10 rounds.

Hi Ionela,

I failed to mention that I drop the first run for averaging.

>
> Also I think 20s is too much of variation for the test results. Like I
> mentioned in my previous emails I think the 7.52 is an anomaly but the
> results should be around the range of 8-9 s.

Also since we are more interested in comparison rather than absolute
numbers did you run tests in a system with no thermal pressure( to see
if there are any improvements)?

Regards
Thara

>
> Regards
> Thara
>
>>
>> Thank you,
>> Ionela.
>>
>
>

--
Regards
Thara