New: A huge unnecessary power consumption with CONFIG_X86_ACPI_CPUFREQ

https://bugzilla.kernel.org/show_bug.cgi?id=215714

Bug ID: 215714
Summary: A huge unnecessary power consumption with
CONFIG_X86_ACPI_CPUFREQ
Product: Power Management
Version: 2.5
Kernel Version: 5.17
Hardware: x86-64
OS: Linux
Tree: Mainline
Status: NEW
Severity: high
Priority: P1
Component: cpufreq
Assignee: [email protected]
Reporter: [email protected]
Regression: No

So, here's the situation.

I have a Ryzen 5800X CPU.

Whenever I watch a 4K youtube video (VP9 codec, Mozilla Firefox, no GPU acceleration, decoded and rendered solely by the CPU) with the ACPI_CPUFREQ driver the power consumption stays around 50-55 Watts while the CPU is constantly hitting or staying around the maximum turbo frequency (~4.75GHz).

Whenever I disable Turbo Boost (echo 0 > /sys/devices/system/cpu/cpufreq/boost), the power consumption instantly deceases to around 39W with no difference in video decoding, i.e. frames are not dropped, decoding is smooth and steady.

We are talking about a staggering 30% decrease in power consumption just by disabling Turbo Boost and limiting CPU frequency to 3.8GHz.

I suppose this is not right and should be fixed/addressed.

I'm using the ondemand governor with default settings.

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https://bugzilla.kernel.org/show_bug.cgi?id=215714

Artem S. Tashkinov ([email protected]) changed:

What |Removed |Added
----------------------------------------------------------------------------

            Summary|A huge unnecessary power    |A huge unnecessary power
                   |consumption with            |consumption with
                   |CONFIG_X86_ACPI_CPUFREQ     |CONFIG_X86_ACPI_CPUFREQ and
                   |                            |ondemand governor

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https://bugzilla.kernel.org/show_bug.cgi?id=215714

Zhang Rui ([email protected]) changed:

What |Removed |Added
----------------------------------------------------------------------------

                 CC|                            |[email protected]
            Summary|A huge unnecessary power    |A huge unnecessary power
                   |consumption with            |consumption with
                   |CONFIG_X86_ACPI_CPUFREQ and |CONFIG_X86_ACPI_CPUFREQ and
                   |ondemand governor           |ondemand governor - Ryzen
                   |                            |5800X

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https://bugzilla.kernel.org/show_bug.cgi?id=215714

--- Comment #1 from Artem S. Tashkinov ([email protected]) --- This is reproducible for other CPUs as well.

Watching HW accelerated videos in Firefox results in ~40% higher power consumption than necessary to actually play them.

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