The DevTerm A-06 core modules have 6 processor cores, arranged in ARM big.LITTLE heterogeneous computing architecture, combining relatively battery-saving and slower processor ( LITTLE : #0, #1, #2, #3 ) cores with relatively more powerful and power-hungry ( big : #4, #5) ones. You could have to option to turn on or off any core at any time according to your own computing needs.
For example, the command to turn on core #5 is:
sudo sh -c "echo 1 > /sys/devices/system/cpu/cpu5/online"
the command to turn off core #0 is:
sudo sh -c "echo 0 > /sys/devices/system/cpu/cpu0/online"
The result could be verified with
In addition, user could simply use a tool called
cpupower-gui to configure core frequency and CPU scheduling governor:
powersave mode aggressively keeps CPU cores running at the lowest frequency, the
performance mode always run in highest frequency.
conservative will automatically adjust CPU frequency according to application requirement, to achieve the balance between power-saving and performance. That means, if you like, under extreme situations, the A-06 core module could be run either with only one LITTLE core at 408MHz, or with all six cores at 1416MHz. There is ample room in between for fine-tuning and dynamic controls. e.g. Android users love
schedutil mode for its efficiency, for details about scaling and different scaling governors, please refer to:
Similarly, A-06 GPU frequency and scheduling could be configured by setting:
By default, the A-06 core modules are set to run on 4 cores, with
conservative scaling governor, at 408-1000MHz.
You could play with these frequency scaling parameters according to your specific application needs. For example, with these following commands, the A-06 core could achieve potentially better power management than CM3.
echo schedutil > /sys/devices/system/cpu/cpufreq/policy0/scaling_governor echo 800000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq echo 800000 > /sys/devices/system/cpu/cpu1/cpufreq/scaling_max_freq echo 0 > /sys/devices/system/cpu/cpu2/online echo 0 > /sys/devices/system/cpu/cpu3/online echo simple_ondemand > /sys/devices/platform/ff9a0000.gpu/devfreq/ff9a0000.gpu/governor echo 400000000 > /sys/devices/platform/ff9a0000.gpu/devfreq/ff9a0000.gpu/max_freq