A72 cores won't go beyond 750 MHz


#1

I am benchmarking the individual cores of the X20 board and I found that the A72 cores can only reach 750 MHz. I installed Linux on the board and set the CPUFreq governors to userspace to be able to change the clock frequency at will. Then, I use the “mhz” program of the lmbench3 benchmark suite to measure the actual frequency. For the A53 cores, the measured frequency matches the instructed one, however, this is not the case with the A72 cores: when setting the frequency to the minimum (i.e., 338 MHz) the frequency I measure is 500 MHz and when I increase the frequency all the way to 2.3 GHz the measured frequency saturates at 750 MHz. In summary, the kernel frequency scaling directive does not translate into the actual hardware changing its frequency.

Does this mean I got a board with a hardware bug or other people also experience similar issues?