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... Best regards, Krzysztof
