psuilt.cpu_freq(percpu=True) may not return all CPUs on linux

[andrewjcg]

The implementation for cpu_freq for linux (in _pslinux.py) parses the policy files under /sys/devices/system/cpu/cpufreq/policy* and assumes there's a one-to-one mapping from these to online CPUs. However, it may be the case that a single policy applies to multiple online CPUs, in which case these CPUs will be listed in /sys/devices/system/cpu/cpufreq/policy*/affected_cpus and a separate policy for this CPU may not be listed (https://www.kernel.org/doc/html/v4.14/admin-guide/pm/cpufreq.html#policy-interface-in-sysfs).

This can cause the psutil.tests.test_system.TestSystemAPIs.test_cpu_freq test to fail.

[giampaolo]

What action do you propose? I'm not sure I understand the problem enough to have a solution.

[andrewjcg]

I think the code that parses these might also need to parse /sys/devices/system/cpu/cpufreq/policy*/affected_cpus to find the cpu # that the policy applies to, rather than relying on the # found in policy*.

[amanusk]

@giampaolo, @andrewjcg, does #1481 fix this?

[giampaolo]

Mmm I think yes but I'm not sure. This ticket talks about a failing psutil.tests.test_system.TestSystemAPIs.test_cpu_freq. @andrewjcg's does it still fail with latest master?

[no-response]

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