Re: [PATCH 3/3] ARM: exynos_defconfig: Enable Energy Model framework

[Lukasz Luba]

Hi Bartek,

On 1/31/20 1:30 PM, Bartlomiej Zolnierkiewicz 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"?

I need to check if this xu3 ina2xx can aggregate energy or
it's only drained-current-at-that-moment value.

Regards,
Lukasz

> Best regards,
> --
> Bartlomiej Zolnierkiewicz
> Samsung R&D Institute Poland
> Samsung Electronics
>
> > Signed-off-by: Lukasz Luba <lukasz.luba@xxxxxxx>
> > ---
> >   arch/arm/configs/exynos_defconfig | 1 +
> >   1 file changed, 1 insertion(+)
> >
> > diff --git a/arch/arm/configs/exynos_defconfig b/arch/arm/configs/exynos_defconfig
> > index 1db857056992..c0f8ecabc607 100644
> > --- a/arch/arm/configs/exynos_defconfig
> > +++ b/arch/arm/configs/exynos_defconfig
> > @@ -18,6 +18,7 @@ CONFIG_ZBOOT_ROM_BSS=0x0
> >   CONFIG_ARM_APPENDED_DTB=y
> >   CONFIG_ARM_ATAG_DTB_COMPAT=y
> >   CONFIG_CMDLINE="root=/dev/ram0 rw ramdisk=8192 initrd=0x41000000,8M console=ttySAC1,115200 init=/linuxrc mem=256M"
> > +CONFIG_ENERGY_MODEL=y
> >   CONFIG_CPU_FREQ=y
> >   CONFIG_CPU_FREQ_STAT=y
> >   CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND=y