Re: [PATCH 2/2] PM / arch: x86: MSR_IA32_ENERGY_PERF_BIAS sysfs interface

[Hannes Reinecke]

On 3/21/19 11:20 PM, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
>
> The Performance and Energy Bias Hint (EPB) is expected to be set by
> user space through the generic MSR interface, but that interface is
> not particularly nice and there are security concerns regarding it,
> so it is not always available.
>
> For this reason, add a sysfs interface for reading and updating the
> EPB, in the form of a new attribute, energy_perf_bias, located
> under /sys/devices/system/cpu/cpu#/power/ for online CPUs that
> support the EPB feature.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> ---
>   Documentation/ABI/testing/sysfs-devices-system-cpu |   18 ++++
>   Documentation/admin-guide/pm/intel_epb.rst         |   27 ++++++
>   arch/x86/kernel/cpu/intel_epb.c                    |   93 ++++++++++++++++++++-
>   3 files changed, 134 insertions(+), 4 deletions(-)
Reviewed-by: Hannes Reinecke <hare@xxxxxxxx>

Cheers,

Hannes
--
Dr. Hannes Reinecke		   Teamlead Storage & Networking
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