I've recently bought a nanopi NEO2 which features an Allwinner H5. On FriendlyArm website (and on Allwinner's too) it is stated that the H5 is clocked 1.5Ghz. I need to perform some heavy job and and noticed that the cpu frequency hits, at full power, only 1Ghz. I checked using cpufreq-info and I got:
CPUs which run at the same hardware frequency: 0 1 2 3
CPUs which need to have their frequency coordinated by software: 0 1 2 3
maximum transition latency: 244 us.
Nope. Software doesn't know that much about hardware in this case. NEO2 has no voltage regulation and H5 is fed with 1.1V which limits maximum cpufreq on this board to 812 MHz (maybe 864 MHz). FriendlyELEC learned from a conversation with open source community that with mainline kernel they could make use of DVFS (dynamic voltage frequency scaling), something that still seems not possible with Allwinner's BSP. As a consequenze they dropped Allwinner's software offerings, rely on mainline u-boot/