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SubjectRe: [PATCH] cpufreq: intel_pstate: Show different max frequency with turbo 3 and HWP
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On Wednesday, July 18, 2018 11:51:59 PM CEST Srinivas Pandruvada wrote:
> On HWP platforms with Turbo 3.0, the HWP capability max ratio shows the
> maximum ratio of that core, which can be different than other cores. If
> we show the correct maximum frequency in cpufreq sysfs via
> cpuinfo_max_freq and scaling_max_freq then, user can know which cores
> can run faster for pinning some high priority tasks.
>
> Currently the max turbo frequency is shown as max frequency, which is
> the max of all cores, even if some cores can't reach that frequency
> even for single threaded workload.
>
> But it is possible that max ratio in HWP capabilities is set as 0xFF or
> some high invalid value (E.g. One KBL NUC). Since the actual performance
> can never exceed 1 core turbo frequency from MSR TURBO_RATIO_LIMIT, we
> use this as a bound check.
>
> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
> ---
> drivers/cpufreq/intel_pstate.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
> index ece120da3353..97096127d015 100644
> --- a/drivers/cpufreq/intel_pstate.c
> +++ b/drivers/cpufreq/intel_pstate.c
> @@ -2072,6 +2072,15 @@ static int __intel_pstate_cpu_init(struct cpufreq_policy *policy)
> cpu->pstate.max_pstate : cpu->pstate.turbo_pstate;
> policy->cpuinfo.max_freq *= cpu->pstate.scaling;
>
> + if (hwp_active) {
> + unsigned int max_freq;
> +
> + max_freq = global.turbo_disabled ?
> + cpu->pstate.max_freq : cpu->pstate.turbo_freq;
> + if (max_freq < policy->cpuinfo.max_freq)
> + policy->cpuinfo.max_freq = max_freq;
> + }
> +
> intel_pstate_init_acpi_perf_limits(policy);
>
> policy->fast_switch_possible = true;
>

Applied, thanks!


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