linux-kernel - Re: [PATCH v2 4/4] cpufreq: intel_pstate: Take CPUFREQ_GOV_FLAG_STRICT

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Date:   Tue, 10 Nov 2020 08:18:04 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:     Linux PM <linux-pm@...r.kernel.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        Zhang Rui <rui.zhang@...el.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Doug Smythies <dsmythies@...us.net>
Subject: Re: [PATCH v2 4/4] cpufreq: intel_pstate: Take
 CPUFREQ_GOV_FLAG_STRICT_TARGET into account

On 09-11-20, 17:55, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> 
> Make intel_pstate take the new CPUFREQ_GOV_FLAG_STRICT_TARGET
> governor flag into account when it operates in the passive mode with
> HWP enabled, so as to fix the "powersave" governor behavior in that
> case (currently, HWP is allowed to scale the performance all the way
> up to the policy max limit when the "powersave" governor is used,
> but it should be constrained to the policy min limit then).
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> ---
>  drivers/cpufreq/intel_pstate.c |   16 +++++++++-------
>  1 file changed, 9 insertions(+), 7 deletions(-)
> 
> Index: linux-pm/drivers/cpufreq/intel_pstate.c
> ===================================================================
> --- linux-pm.orig/drivers/cpufreq/intel_pstate.c
> +++ linux-pm/drivers/cpufreq/intel_pstate.c
> @@ -2527,7 +2527,7 @@ static void intel_cpufreq_trace(struct c
>  }
>  
>  static void intel_cpufreq_adjust_hwp(struct cpudata *cpu, u32 target_pstate,
> -				     bool fast_switch)
> +				     bool strict, bool fast_switch)
>  {
>  	u64 prev = READ_ONCE(cpu->hwp_req_cached), value = prev;
>  
> @@ -2539,7 +2539,7 @@ static void intel_cpufreq_adjust_hwp(str
>  	 * field in it, so opportunistically update the max too if needed.
>  	 */
>  	value &= ~HWP_MAX_PERF(~0L);
> -	value |= HWP_MAX_PERF(cpu->max_perf_ratio);
> +	value |= HWP_MAX_PERF(strict ? target_pstate : cpu->max_perf_ratio);
>  
>  	if (value == prev)
>  		return;
> @@ -2562,14 +2562,16 @@ static void intel_cpufreq_adjust_perf_ct
>  			      pstate_funcs.get_val(cpu, target_pstate));
>  }
>  
> -static int intel_cpufreq_update_pstate(struct cpudata *cpu, int target_pstate,
> -				       bool fast_switch)
> +static int intel_cpufreq_update_pstate(struct cpufreq_policy *policy,
> +				       int target_pstate, bool fast_switch)
>  {
> +	struct cpudata *cpu = all_cpu_data[policy->cpu];
>  	int old_pstate = cpu->pstate.current_pstate;
>  
>  	target_pstate = intel_pstate_prepare_request(cpu, target_pstate);
>  	if (hwp_active) {
> -		intel_cpufreq_adjust_hwp(cpu, target_pstate, fast_switch);
> +		intel_cpufreq_adjust_hwp(cpu, target_pstate,
> +					 policy->strict_target, fast_switch);
>  		cpu->pstate.current_pstate = target_pstate;
>  	} else if (target_pstate != old_pstate) {
>  		intel_cpufreq_adjust_perf_ctl(cpu, target_pstate, fast_switch);
> @@ -2609,7 +2611,7 @@ static int intel_cpufreq_target(struct c
>  		break;
>  	}
>  
> -	target_pstate = intel_cpufreq_update_pstate(cpu, target_pstate, false);
> +	target_pstate = intel_cpufreq_update_pstate(policy, target_pstate, false);
>  
>  	freqs.new = target_pstate * cpu->pstate.scaling;
>  
> @@ -2628,7 +2630,7 @@ static unsigned int intel_cpufreq_fast_s
>  
>  	target_pstate = DIV_ROUND_UP(target_freq, cpu->pstate.scaling);
>  
> -	target_pstate = intel_cpufreq_update_pstate(cpu, target_pstate, true);
> +	target_pstate = intel_cpufreq_update_pstate(policy, target_pstate, true);
>  
>  	return target_pstate * cpu->pstate.scaling;
>  }

Acked-by: Viresh Kumar <viresh.kumar@...aro.org>

-- 
viresh