Messages in this thread | | | Subject | Re: [RFC PATCH 0/7] Introduce thermal pressure | From | Lukasz Luba <> | Date | Thu, 11 Oct 2018 13:10:23 +0200 |
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On 10/10/2018 07:30 PM, Thara Gopinath wrote: > Hello Lukasz, > > On 10/10/2018 11:35 AM, Lukasz Luba wrote: >> Hi Thara, >> >> I have run it on Exynos5433 mainline. >> When it is enabled with step_wise thermal governor, >> some of my tests are showing ~30-50% regression (i.e. hackbench), >> dhrystone ~10%. > > That is interesting. If I understand correctly, dhrystone spawns 16 > threads or so and floods the system. In "theory", such a test should not > see any performance improvement and degradation. What is the thermal > activity like in your system? I will try running one of these tests on > hikey960. I use this dhrystone implementation: https://github.com/Keith-S-Thompson/dhrystone/blob/master/v2.2/dry.c It does not span new threads/processes and I pinned it to a single cpu.
My thermal setup is probably different than yours. You have (on hikey960) probably 1 sensor for whole SoC and one thermal zone (if it is this mainline file: arch/arm64/boot/dts/hisilicon/hi3660.dtsi). This thermal zone has two cooling devices - two clusters with dvfs. Your temperature signal read out from that sensor is probably much smoother. When you have sensor inside cluster, the rising factor can be even 20deg/s (for big cores). In my case, there are 4 thermal zones, each cluster has it's private sensor and thermal zone. There is no 'SoC sensor' or 'PCB sensor', which is recommended for IPA. >> >> Could you tell me which thermal governor was used in your case? >> Please also share the name of that benchmark, i will give it a try. >> Is it single threaded compute-intensive? > > Step-wise governor. > I use aobench which is part of phoronix-test-suite. > > Regards > Thara > I have built this aobench and run it pinned to single big cpu: time taskset -c 4 ./aobench The results: 3min-5:30min [mainline] 5:15min-5:50min [+patchset]
The idea is definitely worth to investigate further.
Regards, Lukasz
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