On 1/31/20 2:47 PM, Bartlomiej Zolnierkiewicz wrote: > > On 1/31/20 2:31 PM, Krzysztof Kozlowski wrote: >> On Fri, 31 Jan 2020 at 14:30, Bartlomiej Zolnierkiewicz >> <b.zolnierkie@xxxxxxxxxxx> wrote: >>> >>> >>> Hi, >>> >>> On 1/27/20 10:54 PM, lukasz.luba@xxxxxxx wrote: >>>> From: Lukasz Luba <lukasz.luba@xxxxxxx> >>>> >>>> Enable the Energy Model (EM) brings possibility to use Energy Aware >>>> Scheduler (EAS). This compiles the EM but does not enable to run EAS in >>>> default. The EAS only works with SchedUtil - a CPUFreq governor which >>>> handles direct requests from the scheduler for the frequency change. Thus, >>>> to make EAS working in default, the SchedUtil governor should be >>>> configured as default CPUFreq governor. Although, the EAS might be enabled >>>> in runtime, when the EM is present for CPUs, the SchedUtil is compiled and >>>> then set as CPUFreq governor, i.e.: >>>> >>>> echo schedutil > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor >>>> echo schedutil > /sys/devices/system/cpu/cpu4/cpufreq/scaling_governor >>>> >>>> To check if EAS is ready to work, the read output from the command below >>>> should show '1': >>>> cat /proc/sys/kernel/sched_energy_aware >>>> >>>> To disable EAS in runtime simply 'echo 0' to the file above. >>>> >>>> Some test results, which stress the scheduler on Odroid-XU3: >>>> hackbench -l 500 -s 4096 >>>> With mainline code and with this patch set. >>>> >>>> The tests have been made with and without CONFIG_PROVE_LOCKING (PL) >>>> (which is set to =y in default exynos_defconfig) >>>> >>>> | this patch set | mainline >>>> |-----------------------------------------------|--------------- >>>> | performance | SchedUtil | SchedUtil | performance >>>> | governor | governor | governor | governor >>>> | | w/o EAS | w/ EAS | >>>> ----------------|---------------|---------------|---------------|--------------- >>>> hackbench w/ PL | 12.7s | 11.7s | 12.0s | 13.0s - 12.2s >>>> hackbench w/o PL| 9.2s | 8.1s | 8.2s | 9.2s - 8.4s >>> >>> Would you happen to have measurements of how much power is >>> saved by running hackbench using "SchedUtil governor w/ EAS" >>> instead of "SchedUtil governor w/o EAS"? >> >> That's a good point and quite important reason behind enabling (or not) EAS... > > IIUC EAS is enabled by default if you use SchedUtil > governor and Energy Model is available on you platform. > > [ SchedUtil governor is enabled in exynos_defconfig > although not enabled by default currently. ] s/enabled/used/ Best regards, -- Bartlomiej Zolnierkiewicz Samsung R&D Institute Poland Samsung Electronics
