Re: [PATCH v4 0/2] add SW BOOST support for CPPC
From: Viresh Kumar
Date: Thu May 21 2020 - 23:55:03 EST
On 22-05-20, 11:34, Xiongfeng Wang wrote:
> ACPI spec 6.2 section 8.4.7.1 provide the following two CPC registers.
>
> "Highest performance is the absolute maximum performance an individual
> processor may reach, assuming ideal conditions. This performance level
> may not be sustainable for long durations, and may only be achievable if
> other platform components are in a specific state; for example, it may
> require other processors be in an idle state.
>
> Nominal Performance is the maximum sustained performance level of the
> processor, assuming ideal operating conditions. In absence of an
> external constraint (power, thermal, etc.) this is the performance level
> the platform is expected to be able to maintain continuously. All
> processors are expected to be able to sustain their nominal performance
> state simultaneously."
>
> We can use Highest Performance as the max performance in boost mode and
> Nomial Performance as the max performance in non-boost mode. If the
> Highest Performance is greater than the Nominal Performance, we assume
> SW BOOST is supported.
>
> v3->v4:
> run 'boost_set_msr_each' for each CPU in the policy rather than
> each CPU in the system for 'acpi-cpufreq'
> add 'Suggested-by'
Acked-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
--
viresh