Re: [PATCH v5] Force cppc_cpufreq to report values in KHz to fix user space reporting

From: Al Stone
Date: Mon Aug 01 2016 - 16:14:12 EST


On 07/20/2016 03:10 PM, Al Stone wrote:
> When CPPC is being used by ACPI on arm64, user space tools such as
> cpupower report CPU frequency values from sysfs that are incorrect.
>
> What the driver was doing was reporting the values given by ACPI tables
> in whatever scale was used to provide them. However, the ACPI spec
> defines the CPPC values as unitless abstract numbers. Internal kernel
> structures such as struct perf_cap, in contrast, expect these values
> to be in KHz. When these struct values get reported via sysfs, the
> user space tools also assume they are in KHz, causing them to report
> incorrect values (for example, reporting a CPU frequency of 1MHz when
> it should be 1.8GHz).
> [snip...]

Ping? If anyone has sent comments, I have not received them.

Thanks in advance for the time and effort. I know merge window can be
a very busy time.

--
ciao,
al
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Al Stone
Software Engineer
Red Hat, Inc.
ahs3@xxxxxxxxxx
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