Hi Vincent, On 10/16/2018 07:11 PM, Vincent Guittot wrote: > Hi Lukasz, > > On Thu, 11 Oct 2018 at 13:10, Lukasz Luba <l.l...@partner.samsung.com> wrote: >> >> >> >> 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 > > Why have you pinned the test only on CPU4 ? > Goal of thermal pressure is to inform the scheduler of reduced compute > capacity and help the scheduler to take better decision in tasks > placement. > So I would not expect perf impact on your test as the bench will stay > pinned on the cpu4 > That being said you obviously have perf impact as shown below in your results > And other tasks on the system are not pinned and might come and > disturb your bench Unpinned runs on this platform have a lot of variation. The tests take even 16min to finish.
Regards, Lukasz > >> The results: >> 3min-5:30min [mainline] >> 5:15min-5:50min [+patchset] >> >> The idea is definitely worth to investigate further. > > Yes I agree > > Vincent >> >> Regards, >> Lukasz >> >> >> > >
