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

From: Thara Gopinath <thara.gopinath@linaro.org>
To: Ionela Voinescu <ionela.voinescu@arm.com>,
	mingo@redhat.com, peterz@infradead.org, rui.zhang@intel.com
Cc: linux-kernel@vger.kernel.org, amit.kachhap@gmail.com,
	viresh.kumar@linaro.org, javi.merino@kernel.org,
	edubezval@gmail.com, daniel.lezcano@linaro.org,
	vincent.guittot@linaro.org, nicolas.dechesne@linaro.org,
	bjorn.andersson@linaro.org, dietmar.eggemann@arm.com
Subject: Re: [PATCH V2 0/3] Introduce Thermal Pressure
Date: Tue, 30 Apr 2019 11:57:54 -0400	[thread overview]
Message-ID: <5CC87082.20802@linaro.org> (raw)
In-Reply-To: <8eed9601-8bbb-9f62-f786-f08bd4a72907@arm.com>

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.

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.

Regards
Thara

> 
> Thank you,
> Ionela.
> 

-- 
Regards
Thara