Re: [PATCH v1 4/4] cpufreq: intel_pstate: Implement the ->adjust_perf() callback

Peter Zijlstra
2020-12-08T12:44:36Z

On Mon, Dec 07, 2020 at 05:38:58PM +0100, Rafael J. Wysocki wrote:

> +static void intel_cpufreq_adjust_perf(unsigned int cpunum,
> + unsigned long min_perf,
> + unsigned long target_perf,
> + unsigned long capacity)
> +{
> + struct cpudata *cpu = all_cpu_data[cpunum];
> + int old_pstate = cpu->pstate.current_pstate;
> + int cap_pstate, min_pstate, max_pstate, target_pstate;
> +
> + update_turbo_state();
> + cap_pstate = global.turbo_disabled ? cpu->pstate.max_pstate :
> + cpu->pstate.turbo_pstate;
> +
> + /* Optimization: Avoid unnecessary divisions. */
> +
> + target_pstate = cap_pstate;
> + if (target_perf < capacity)
> + target_pstate = DIV_ROUND_UP(cap_pstate * target_perf, capacity);
> +
> + min_pstate = cap_pstate;
> + if (min_perf < capacity)
> + min_pstate = DIV_ROUND_UP(cap_pstate * min_perf, capacity);
> +
> + if (min_pstate < cpu->pstate.min_pstate)
> + min_pstate = cpu->pstate.min_pstate;
> +
> + if (min_pstate < cpu->min_perf_ratio)
> + min_pstate = cpu->min_perf_ratio;
> +
> + max_pstate = min(cap_pstate, cpu->max_perf_ratio);
> + if (max_pstate < min_pstate)
> + max_pstate = min_pstate;
> +
> + target_pstate = clamp_t(int, target_pstate, min_pstate, max_pstate);
> +
> + intel_cpufreq_adjust_hwp(cpu, min_pstate, max_pstate, target_pstate, true);

I'm confused... HWP doesn't do pstate, yet everything here is now called
pstate, help?

> +
> + cpu->pstate.current_pstate = target_pstate;
> + intel_cpufreq_trace(cpu, INTEL_PSTATE_TRACE_FAST_SWITCH, old_pstate);
> +}