Failed to set CPUFreq ondemand governor's sampling_rate for Linux kernel 4.4

[Leo-Yan]

Hi,

I saw Lisa set ondemand governor's sampling_rate in the folder: /sys/devices/system/cpu/cpufreq/ondemand/sampling_rate; but when I run Linux kernel 4.4 the folder has been changed as: /sys/devices/system/cpu/cpufreq/policy0/ondemand/sampling_rate and /sys/devices/system/cpu/cpufreq/policy1/ondemand/sampling_rate.

So finally this will introduce failure when run LISA for Juno's profiling with kernel 4.4.

Thanks,
Leo Yan

[derkling]

We should probably make the hard-coded path in:
https://github.com/ARM-software/devlib/blob/master/devlib/module/cpufreq.py#L45
more generic. Which means, for example, at init time to probe which path as to be used.

[derkling]

@setrofim any update on this side? Maybe WA implementation already address this issue?
The "policyN" format seems to be standard for kernel >v4.4 with more than one frequency domain.