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Message-ID: <2dbded5a-b353-480c-a2ea-ed246f5c0b27@amd.com>
Date: Fri, 7 Feb 2025 16:14:18 +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 02/14] cpufreq/amd-pstate: Drop min and max cached
frequencies
Hello Mario,
On 2/7/2025 3:26 AM, Mario Limonciello wrote:
> From: Mario Limonciello <mario.limonciello@....com>
>
> Use the perf_to_freq helpers to calculate this on the fly.
I think there is a benefit to having the min/max_limit_freq values cached.
These values help us avoid unnecessary amd_pstate_update_min_max_limit() calls in
majority of cases (where the policy->min/max values didnt change).
For the cpudata->min/max_freq values, I think there is little value in caching them,
i.e. only used in amd_pstate_cpu_boost_update() and show_amd_pstate_max_freq(), which
are not supposed to be called very frequently.
So, I propose we keep the cpudata->min/max_limit_freq variables and remove the
cpudata->min/max_freq ones. Thoughts?
Thanks,
Dhananjay
>
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> ---
> drivers/cpufreq/amd-pstate-ut.c | 14 +++----
> drivers/cpufreq/amd-pstate.c | 74 ++++++++++-----------------------
> drivers/cpufreq/amd-pstate.h | 8 ----
> 3 files changed, 29 insertions(+), 67 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 573643654e8d6..668377f55b630 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -615,8 +615,6 @@ static int amd_pstate_update_min_max_limit(struct cpufreq_policy *policy)
>
> WRITE_ONCE(cpudata->max_limit_perf, max_limit_perf);
> WRITE_ONCE(cpudata->min_limit_perf, min_limit_perf);
> - WRITE_ONCE(cpudata->max_limit_freq, policy->max);
> - WRITE_ONCE(cpudata->min_limit_freq, policy->min);
>
> return 0;
> }
> @@ -628,8 +626,7 @@ static int amd_pstate_update_freq(struct cpufreq_policy *policy,
> struct amd_cpudata *cpudata = policy->driver_data;
> u8 des_perf;
>
> - if (policy->min != cpudata->min_limit_freq || policy->max != cpudata->max_limit_freq)
> - amd_pstate_update_min_max_limit(policy);
> + amd_pstate_update_min_max_limit(policy);
>
> freqs.old = policy->cur;
> freqs.new = target_freq;
> @@ -684,8 +681,7 @@ static void amd_pstate_adjust_perf(unsigned int cpu,
>
> cpudata = policy->driver_data;
>
> - if (policy->min != cpudata->min_limit_freq || policy->max != cpudata->max_limit_freq)
> - amd_pstate_update_min_max_limit(policy);
> + amd_pstate_update_min_max_limit(policy);
>
> cap_perf = READ_ONCE(cpudata->highest_perf);
> min_limit_perf = READ_ONCE(cpudata->min_limit_perf);
> @@ -717,7 +713,7 @@ 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 +897,25 @@ 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) {
> + min_freq = quirks->lowest_freq;
> + } else
> + min_freq = cppc_perf.lowest_freq;
>
> /**
> * Below values need to be initialized correctly, otherwise driver will fail to load
> @@ -937,12 +923,15 @@ 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) {
> - 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 +943,9 @@ 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 +976,11 @@ 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 +1004,6 @@ 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 +1061,10 @@ 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 +1422,10 @@ 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 +1456,13 @@ 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);
>
> /*
> diff --git a/drivers/cpufreq/amd-pstate.h b/drivers/cpufreq/amd-pstate.h
> index 19d405c6d805e..472044a1de43b 100644
> --- a/drivers/cpufreq/amd-pstate.h
> +++ b/drivers/cpufreq/amd-pstate.h
> @@ -44,10 +44,6 @@ struct amd_aperf_mperf {
> * priority.
> * @min_limit_perf: Cached value of the performance corresponding to policy->min
> * @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 +73,7 @@ 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 nominal_freq;
> u32 lowest_nonlinear_freq;
>
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