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Message-ID: <87a59577-3b66-49ff-a0b5-0cddaa670a27@amd.com>
Date: Wed, 19 Feb 2025 13:30:43 +0530
From: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>
To: Mario Limonciello <superm1@...nel.org>,
 "Gautham R . Shenoy" <gautham.shenoy@....com>,
 Perry Yuan <perry.yuan@....com>
Cc: "open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
 <linux-kernel@...r.kernel.org>,
 "open list:CPU FREQUENCY SCALING FRAMEWORK" <linux-pm@...r.kernel.org>,
 Mario Limonciello <mario.limonciello@....com>
Subject: Re: [PATCH v3 03/18] cpufreq/amd-pstate: Drop min and max cached
 frequencies

On 2/18/2025 3:36 AM, Mario Limonciello wrote:
> From: Mario Limonciello <mario.limonciello@....com>
> 
> Use the perf_to_freq helpers to calculate this on the fly.

Can we call out the below change (in the -1550,7 +1525,8 code chunk) in 
the commit message, or split it out to different patch 

* Adding the if check in amd_pstate_epp_update_limit()

> 
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> --
We need one more hyphen here I think i.e."---", otherwise the version info is 
showing up in the commit message

> v3:
>  * Fix calc error for min_freq
> v2:
>  * Keep cached limits
> ---
>  drivers/cpufreq/amd-pstate-ut.c | 14 +++----
>  drivers/cpufreq/amd-pstate.c    | 70 +++++++++++----------------------
>  drivers/cpufreq/amd-pstate.h    |  9 +----
>  3 files changed, 32 insertions(+), 61 deletions(-)
> 
> diff --git a/drivers/cpufreq/amd-pstate-ut.c b/drivers/cpufreq/amd-pstate-ut.c
> index 3a0a380c3590c..445278cf40b61 100644
> --- a/drivers/cpufreq/amd-pstate-ut.c
> +++ b/drivers/cpufreq/amd-pstate-ut.c
> @@ -214,14 +214,14 @@ static void amd_pstate_ut_check_freq(u32 index)
>  			break;
>  		cpudata = policy->driver_data;
>  
> -		if (!((cpudata->max_freq >= cpudata->nominal_freq) &&
> +		if (!((policy->cpuinfo.max_freq >= cpudata->nominal_freq) &&
>  			(cpudata->nominal_freq > cpudata->lowest_nonlinear_freq) &&
> -			(cpudata->lowest_nonlinear_freq > cpudata->min_freq) &&
> -			(cpudata->min_freq > 0))) {
> +			(cpudata->lowest_nonlinear_freq > policy->cpuinfo.min_freq) &&
> +			(policy->cpuinfo.min_freq > 0))) {
>  			amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_FAIL;
>  			pr_err("%s cpu%d max=%d >= nominal=%d > lowest_nonlinear=%d > min=%d > 0, the formula is incorrect!\n",
> -				__func__, cpu, cpudata->max_freq, cpudata->nominal_freq,
> -				cpudata->lowest_nonlinear_freq, cpudata->min_freq);
> +				__func__, cpu, policy->cpuinfo.max_freq, cpudata->nominal_freq,
> +				cpudata->lowest_nonlinear_freq, policy->cpuinfo.min_freq);
>  			goto skip_test;
>  		}
>  
> @@ -233,13 +233,13 @@ static void amd_pstate_ut_check_freq(u32 index)
>  		}
>  
>  		if (cpudata->boost_supported) {
> -			if ((policy->max == cpudata->max_freq) ||
> +			if ((policy->max == policy->cpuinfo.max_freq) ||
>  					(policy->max == cpudata->nominal_freq))
>  				amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_PASS;
>  			else {
>  				amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_FAIL;
>  				pr_err("%s cpu%d policy_max=%d should be equal cpu_max=%d or cpu_nominal=%d !\n",
> -					__func__, cpu, policy->max, cpudata->max_freq,
> +					__func__, cpu, policy->max, policy->cpuinfo.max_freq,
>  					cpudata->nominal_freq);
>  				goto skip_test;
>  			}
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 87c605348a3dc..a7c41f915b46e 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -717,7 +717,7 @@ static int amd_pstate_cpu_boost_update(struct cpufreq_policy *policy, bool on)
>  	int ret = 0;
>  
>  	nominal_freq = READ_ONCE(cpudata->nominal_freq);
> -	max_freq = READ_ONCE(cpudata->max_freq);
> +	max_freq = perf_to_freq(cpudata, READ_ONCE(cpudata->highest_perf));
>  
>  	if (on)
>  		policy->cpuinfo.max_freq = max_freq;
> @@ -901,35 +901,26 @@ static u32 amd_pstate_get_transition_latency(unsigned int cpu)
>  static int amd_pstate_init_freq(struct amd_cpudata *cpudata)
>  {
>  	int ret;
> -	u32 min_freq, max_freq;
> -	u32 nominal_freq, lowest_nonlinear_freq;
> +	u32 min_freq, nominal_freq, lowest_nonlinear_freq;
>  	struct cppc_perf_caps cppc_perf;
>  
>  	ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);
>  	if (ret)
>  		return ret;
>  
> -	if (quirks && quirks->lowest_freq)
> -		min_freq = quirks->lowest_freq;
> -	else
> -		min_freq = cppc_perf.lowest_freq;
> -
>  	if (quirks && quirks->nominal_freq)
>  		nominal_freq = quirks->nominal_freq;
>  	else
>  		nominal_freq = cppc_perf.nominal_freq;
>  
> -	min_freq *= 1000;
>  	nominal_freq *= 1000;
> -
>  	WRITE_ONCE(cpudata->nominal_freq, nominal_freq);
> -	WRITE_ONCE(cpudata->min_freq, min_freq);
> -
> -	max_freq = perf_to_freq(cpudata, cpudata->highest_perf);
> -	lowest_nonlinear_freq = perf_to_freq(cpudata, cpudata->lowest_nonlinear_perf);
>  
> -	WRITE_ONCE(cpudata->lowest_nonlinear_freq, lowest_nonlinear_freq);
> -	WRITE_ONCE(cpudata->max_freq, max_freq);
> +	if (quirks && quirks->lowest_freq) {

We can avoid the "{" for single line if statement, to keep checkpatch happy 

> +		min_freq = quirks->lowest_freq;
> +	} else
> +		min_freq = cppc_perf.lowest_freq;
> +	min_freq *= 1000;

I see that this min_freq part of the code is unchanged, just moved few lines below. 
If the moving is unintended can we avoid it, so that the diff is optimal.

>  
>  	/**
>  	 * Below values need to be initialized correctly, otherwise driver will fail to load
> @@ -937,12 +928,15 @@ static int amd_pstate_init_freq(struct amd_cpudata *cpudata)
>  	 * lowest_nonlinear_freq is a value between [min_freq, nominal_freq]
>  	 * Check _CPC in ACPI table objects if any values are incorrect
>  	 */
> -	if (min_freq <= 0 || max_freq <= 0 || nominal_freq <= 0 || min_freq > max_freq) {

Shouldn't we retain these sanity checks for min_freq and max_freq?

Thanks,
Dhananjay

> -		pr_err("min_freq(%d) or max_freq(%d) or nominal_freq(%d) value is incorrect\n",
> -			min_freq, max_freq, nominal_freq);
> +	if (nominal_freq <= 0) {
> +		pr_err("nominal_freq(%d) value is incorrect\n",
> +			nominal_freq);
>  		return -EINVAL;
>  	}
>  
> +	lowest_nonlinear_freq = perf_to_freq(cpudata, cpudata->lowest_nonlinear_perf);
> +	WRITE_ONCE(cpudata->lowest_nonlinear_freq, lowest_nonlinear_freq);
> +
>  	if (lowest_nonlinear_freq <= min_freq || lowest_nonlinear_freq > nominal_freq) {
>  		pr_err("lowest_nonlinear_freq(%d) value is out of range [min_freq(%d), nominal_freq(%d)]\n",
>  			lowest_nonlinear_freq, min_freq, nominal_freq);
> @@ -954,9 +948,9 @@ static int amd_pstate_init_freq(struct amd_cpudata *cpudata)
>  
>  static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
>  {
> -	int min_freq, max_freq, ret;
> -	struct device *dev;
>  	struct amd_cpudata *cpudata;
> +	struct device *dev;
> +	int ret;
>  
>  	/*
>  	 * Resetting PERF_CTL_MSR will put the CPU in P0 frequency,
> @@ -987,17 +981,11 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
>  	if (ret)
>  		goto free_cpudata1;
>  
> -	min_freq = READ_ONCE(cpudata->min_freq);
> -	max_freq = READ_ONCE(cpudata->max_freq);
> -
>  	policy->cpuinfo.transition_latency = amd_pstate_get_transition_latency(policy->cpu);
>  	policy->transition_delay_us = amd_pstate_get_transition_delay_us(policy->cpu);
>  
> -	policy->min = min_freq;
> -	policy->max = max_freq;
> -
> -	policy->cpuinfo.min_freq = min_freq;
> -	policy->cpuinfo.max_freq = max_freq;
> +	policy->cpuinfo.min_freq = policy->min = perf_to_freq(cpudata, cpudata->lowest_perf);
> +	policy->cpuinfo.max_freq = policy->max = perf_to_freq(cpudata, cpudata->highest_perf);
>  
>  	policy->boost_enabled = READ_ONCE(cpudata->boost_supported);
>  
> @@ -1021,9 +1009,6 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
>  		goto free_cpudata2;
>  	}
>  
> -	cpudata->max_limit_freq = max_freq;
> -	cpudata->min_limit_freq = min_freq;
> -
>  	policy->driver_data = cpudata;
>  
>  	if (!current_pstate_driver->adjust_perf)
> @@ -1081,14 +1066,10 @@ static int amd_pstate_cpu_suspend(struct cpufreq_policy *policy)
>  static ssize_t show_amd_pstate_max_freq(struct cpufreq_policy *policy,
>  					char *buf)
>  {
> -	int max_freq;
>  	struct amd_cpudata *cpudata = policy->driver_data;
>  
> -	max_freq = READ_ONCE(cpudata->max_freq);
> -	if (max_freq < 0)
> -		return max_freq;
>  
> -	return sysfs_emit(buf, "%u\n", max_freq);
> +	return sysfs_emit(buf, "%u\n", perf_to_freq(cpudata, READ_ONCE(cpudata->highest_perf)));
>  }
>  
>  static ssize_t show_amd_pstate_lowest_nonlinear_freq(struct cpufreq_policy *policy,
> @@ -1446,10 +1427,10 @@ static bool amd_pstate_acpi_pm_profile_undefined(void)
>  
>  static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
>  {
> -	int min_freq, max_freq, ret;
>  	struct amd_cpudata *cpudata;
>  	struct device *dev;
>  	u64 value;
> +	int ret;
>  
>  	/*
>  	 * Resetting PERF_CTL_MSR will put the CPU in P0 frequency,
> @@ -1480,19 +1461,13 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
>  	if (ret)
>  		goto free_cpudata1;
>  
> -	min_freq = READ_ONCE(cpudata->min_freq);
> -	max_freq = READ_ONCE(cpudata->max_freq);
> -
> -	policy->cpuinfo.min_freq = min_freq;
> -	policy->cpuinfo.max_freq = max_freq;
> +	policy->cpuinfo.min_freq = policy->min = perf_to_freq(cpudata, cpudata->lowest_perf);
> +	policy->cpuinfo.max_freq = policy->max = perf_to_freq(cpudata, cpudata->highest_perf);
>  	/* It will be updated by governor */
>  	policy->cur = policy->cpuinfo.min_freq;
>  
>  	policy->driver_data = cpudata;
>  
> -	policy->min = policy->cpuinfo.min_freq;
> -	policy->max = policy->cpuinfo.max_freq;
> -
>  	policy->boost_enabled = READ_ONCE(cpudata->boost_supported);
>  
>  	/*
> @@ -1550,7 +1525,8 @@ static int amd_pstate_epp_update_limit(struct cpufreq_policy *policy)
>  	struct amd_cpudata *cpudata = policy->driver_data;
>  	u8 epp;
>  
> -	amd_pstate_update_min_max_limit(policy);
> +	if (policy->min != cpudata->min_limit_freq || policy->max != cpudata->max_limit_freq)
> +		amd_pstate_update_min_max_limit(policy);
>  
>  	if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE)
>  		epp = 0;
> diff --git a/drivers/cpufreq/amd-pstate.h b/drivers/cpufreq/amd-pstate.h
> index 19d405c6d805e..0149933692458 100644
> --- a/drivers/cpufreq/amd-pstate.h
> +++ b/drivers/cpufreq/amd-pstate.h
> @@ -46,8 +46,6 @@ struct amd_aperf_mperf {
>   * @max_limit_perf: Cached value of the performance corresponding to policy->max
>   * @min_limit_freq: Cached value of policy->min (in khz)
>   * @max_limit_freq: Cached value of policy->max (in khz)
> - * @max_freq: the frequency (in khz) that mapped to highest_perf
> - * @min_freq: the frequency (in khz) that mapped to lowest_perf
>   * @nominal_freq: the frequency (in khz) that mapped to nominal_perf
>   * @lowest_nonlinear_freq: the frequency (in khz) that mapped to lowest_nonlinear_perf
>   * @cur: Difference of Aperf/Mperf/tsc count between last and current sample
> @@ -77,11 +75,8 @@ struct amd_cpudata {
>  	u8	prefcore_ranking;
>  	u8	min_limit_perf;
>  	u8	max_limit_perf;
> -	u32     min_limit_freq;
> -	u32     max_limit_freq;
> -
> -	u32	max_freq;
> -	u32	min_freq;
> +	u32	min_limit_freq;
> +	u32	max_limit_freq;
>  	u32	nominal_freq;
>  	u32	lowest_nonlinear_freq;
>  


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