Re: [PATCH] cpufreq / CPPC: Add cpuinfo_cur_freq support for CPPC
From: Viresh Kumar
Date: Wed May 23 2018 - 00:08:36 EST
On 22-05-18, 04:42, George Cherian wrote:
> Per Section 8.4.7.1.3 of ACPI 6.2, The platform provides performance
> feedback via set of performance counters. To determine the actual
> performance level delivered over time, OSPM may read a set of
> performance counters from the Reference Performance Counter Register
> and the Delivered Performance Counter Register.
>
> OSPM calculates the delivered performance over a given time period by
> taking a beginning and ending snapshot of both the reference and
> delivered performance counters, and calculating:
>
> delivered_perf = reference_perf X (delta of delivered_perf counter / delta of reference_perf counter).
>
> Implement the above and hook this to the cpufreq->get method.
>
> Signed-off-by: George Cherian <george.cherian@xxxxxxxxxx>
> ---
> drivers/cpufreq/cppc_cpufreq.c | 44 ++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 44 insertions(+)
Acked-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
--
viresh