Re: [PATCH v3 5/6] cpufreq/cppc: set the frequency used for computing the capacity

From: Rafael J. Wysocki
Date: Wed Oct 18 2023 - 13:27:16 EST

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In reply to: Vincent Guittot: "[PATCH v3 5/6] cpufreq/cppc: set the frequency used for computing the capacity"
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On Wed, Oct 18, 2023 at 6:25 PM Vincent Guittot
<vincent.guittot@xxxxxxxxxx> wrote:
>
> Save the frequency associated to the performance that has been used when
> initializing the capacity of CPUs.
> Also, cppc cpufreq driver can register an artificial energy model. In such
> case, it needs the frequency for this compute capacity.
> We moved and renamed cppc_perf_to_khz and cppc_perf_to_khz to use them
> outside cppc_cpufreq in topology_init_cpu_capacity_cppc().
>
> Signed-off-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>

For the changes in drivers/acpi/cppc_acpi.c :

Acked-by: Rafael J. Wysocki <rafael@xxxxxxxxxx>

> ---
> drivers/acpi/cppc_acpi.c | 93 ++++++++++++++++++++++
> drivers/base/arch_topology.c | 15 +++-
> drivers/cpufreq/cppc_cpufreq.c | 141 ++++++---------------------------
> include/acpi/cppc_acpi.h | 2 +
> 4 files changed, 133 insertions(+), 118 deletions(-)
>
> diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
> index 7ff269a78c20..72aae5e87788 100644
> --- a/drivers/acpi/cppc_acpi.c
> +++ b/drivers/acpi/cppc_acpi.c
> @@ -39,6 +39,8 @@
> #include <linux/rwsem.h>
> #include <linux/wait.h>
> #include <linux/topology.h>
> +#include <linux/dmi.h>
> +#include <asm/unaligned.h>
>
> #include <acpi/cppc_acpi.h>
>
> @@ -1760,3 +1762,94 @@ unsigned int cppc_get_transition_latency(int cpu_num)
> return latency_ns;
> }
> EXPORT_SYMBOL_GPL(cppc_get_transition_latency);
> +
> +/* Minimum struct length needed for the DMI processor entry we want */
> +#define DMI_ENTRY_PROCESSOR_MIN_LENGTH 48
> +
> +/* Offset in the DMI processor structure for the max frequency */
> +#define DMI_PROCESSOR_MAX_SPEED 0x14
> +
> +/* Callback function used to retrieve the max frequency from DMI */
> +static void cppc_find_dmi_mhz(const struct dmi_header *dm, void *private)
> +{
> + const u8 *dmi_data = (const u8 *)dm;
> + u16 *mhz = (u16 *)private;
> +
> + if (dm->type == DMI_ENTRY_PROCESSOR &&
> + dm->length >= DMI_ENTRY_PROCESSOR_MIN_LENGTH) {
> + u16 val = (u16)get_unaligned((const u16 *)
> + (dmi_data + DMI_PROCESSOR_MAX_SPEED));
> + *mhz = val > *mhz ? val : *mhz;
> + }
> +}
> +
> +/* Look up the max frequency in DMI */
> +static u64 cppc_get_dmi_max_khz(void)
> +{
> + u16 mhz = 0;
> +
> + dmi_walk(cppc_find_dmi_mhz, &mhz);
> +
> + /*
> + * Real stupid fallback value, just in case there is no
> + * actual value set.
> + */
> + mhz = mhz ? mhz : 1;
> +
> + return (1000 * mhz);
> +}
> +
> +/*
> + * If CPPC lowest_freq and nominal_freq registers are exposed then we can
> + * use them to convert perf to freq and vice versa. The conversion is
> + * extrapolated as an affine function passing by the 2 points:
> + * - (Low perf, Low freq)
> + * - (Nominal perf, Nominal perf)
> + */
> +unsigned int cppc_perf_to_khz(struct cppc_perf_caps *caps, unsigned int perf)
> +{
> + s64 retval, offset = 0;
> + static u64 max_khz;
> + u64 mul, div;
> +
> + if (caps->lowest_freq && caps->nominal_freq) {
> + mul = caps->nominal_freq - caps->lowest_freq;
> + div = caps->nominal_perf - caps->lowest_perf;
> + offset = caps->nominal_freq - div64_u64(caps->nominal_perf * mul, div);
> + } else {
> + if (!max_khz)
> + max_khz = cppc_get_dmi_max_khz();
> + mul = max_khz;
> + div = caps->highest_perf;
> + }
> +
> + retval = offset + div64_u64(perf * mul, div);
> + if (retval >= 0)
> + return retval;
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(cppc_perf_to_khz);
> +
> +unsigned int cppc_khz_to_perf(struct cppc_perf_caps *caps, unsigned int freq)
> +{
> + s64 retval, offset = 0;
> + static u64 max_khz;
> + u64 mul, div;
> +
> + if (caps->lowest_freq && caps->nominal_freq) {
> + mul = caps->nominal_perf - caps->lowest_perf;
> + div = caps->nominal_freq - caps->lowest_freq;
> + offset = caps->nominal_perf - div64_u64(caps->nominal_freq * mul, div);
> + } else {
> + if (!max_khz)
> + max_khz = cppc_get_dmi_max_khz();
> + mul = caps->highest_perf;
> + div = max_khz;
> + }
> +
> + retval = offset + div64_u64(freq * mul, div);
> + if (retval >= 0)
> + return retval;
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(cppc_khz_to_perf);
> diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
> index 9a073c2d2086..2372ce791bb4 100644
> --- a/drivers/base/arch_topology.c
> +++ b/drivers/base/arch_topology.c
> @@ -350,6 +350,7 @@ bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu)
> void topology_init_cpu_capacity_cppc(void)
> {
> struct cppc_perf_caps perf_caps;
> + u64 capacity, capacity_scale;
> int cpu;
>
> if (likely(!acpi_cpc_valid()))
> @@ -365,6 +366,10 @@ void topology_init_cpu_capacity_cppc(void)
> (perf_caps.highest_perf >= perf_caps.nominal_perf) &&
> (perf_caps.highest_perf >= perf_caps.lowest_perf)) {
> raw_capacity[cpu] = perf_caps.highest_perf;
> + capacity_scale = max_t(u64, capacity_scale, raw_capacity[cpu]);
> +
> + per_cpu(capacity_ref_freq, cpu) = cppc_perf_to_khz(&perf_caps, raw_capacity[cpu]);
> +
> pr_debug("cpu_capacity: CPU%d cpu_capacity=%u (raw).\n",
> cpu, raw_capacity[cpu]);
> continue;
> @@ -375,7 +380,15 @@ void topology_init_cpu_capacity_cppc(void)
> goto exit;
> }
>
> - topology_normalize_cpu_scale();
> + for_each_possible_cpu(cpu) {
> + capacity = raw_capacity[cpu];
> + capacity = div64_u64(capacity << SCHED_CAPACITY_SHIFT,
> + capacity_scale);
> + topology_set_cpu_scale(cpu, capacity);
> + pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n",
> + cpu, topology_get_cpu_scale(cpu));
> + }
> +
> schedule_work(&update_topology_flags_work);
> pr_debug("cpu_capacity: cpu_capacity initialization done\n");
>
> diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
> index fe08ca419b3d..822376b0cb78 100644
> --- a/drivers/cpufreq/cppc_cpufreq.c
> +++ b/drivers/cpufreq/cppc_cpufreq.c
> @@ -27,12 +27,6 @@
>
> #include <acpi/cppc_acpi.h>
>
> -/* Minimum struct length needed for the DMI processor entry we want */
> -#define DMI_ENTRY_PROCESSOR_MIN_LENGTH 48
> -
> -/* Offset in the DMI processor structure for the max frequency */
> -#define DMI_PROCESSOR_MAX_SPEED 0x14
> -
> /*
> * This list contains information parsed from per CPU ACPI _CPC and _PSD
> * structures: e.g. the highest and lowest supported performance, capabilities,
> @@ -291,97 +285,9 @@ static inline void cppc_freq_invariance_exit(void)
> }
> #endif /* CONFIG_ACPI_CPPC_CPUFREQ_FIE */
>
> -/* Callback function used to retrieve the max frequency from DMI */
> -static void cppc_find_dmi_mhz(const struct dmi_header *dm, void *private)
> -{
> - const u8 *dmi_data = (const u8 *)dm;
> - u16 *mhz = (u16 *)private;
> -
> - if (dm->type == DMI_ENTRY_PROCESSOR &&
> - dm->length >= DMI_ENTRY_PROCESSOR_MIN_LENGTH) {
> - u16 val = (u16)get_unaligned((const u16 *)
> - (dmi_data + DMI_PROCESSOR_MAX_SPEED));
> - *mhz = val > *mhz ? val : *mhz;
> - }
> -}
> -
> -/* Look up the max frequency in DMI */
> -static u64 cppc_get_dmi_max_khz(void)
> -{
> - u16 mhz = 0;
> -
> - dmi_walk(cppc_find_dmi_mhz, &mhz);
> -
> - /*
> - * Real stupid fallback value, just in case there is no
> - * actual value set.
> - */
> - mhz = mhz ? mhz : 1;
> -
> - return (1000 * mhz);
> -}
> -
> -/*
> - * If CPPC lowest_freq and nominal_freq registers are exposed then we can
> - * use them to convert perf to freq and vice versa. The conversion is
> - * extrapolated as an affine function passing by the 2 points:
> - * - (Low perf, Low freq)
> - * - (Nominal perf, Nominal perf)
> - */
> -static unsigned int cppc_cpufreq_perf_to_khz(struct cppc_cpudata *cpu_data,
> - unsigned int perf)
> -{
> - struct cppc_perf_caps *caps = &cpu_data->perf_caps;
> - s64 retval, offset = 0;
> - static u64 max_khz;
> - u64 mul, div;
> -
> - if (caps->lowest_freq && caps->nominal_freq) {
> - mul = caps->nominal_freq - caps->lowest_freq;
> - div = caps->nominal_perf - caps->lowest_perf;
> - offset = caps->nominal_freq - div64_u64(caps->nominal_perf * mul, div);
> - } else {
> - if (!max_khz)
> - max_khz = cppc_get_dmi_max_khz();
> - mul = max_khz;
> - div = caps->highest_perf;
> - }
> -
> - retval = offset + div64_u64(perf * mul, div);
> - if (retval >= 0)
> - return retval;
> - return 0;
> -}
> -
> -static unsigned int cppc_cpufreq_khz_to_perf(struct cppc_cpudata *cpu_data,
> - unsigned int freq)
> -{
> - struct cppc_perf_caps *caps = &cpu_data->perf_caps;
> - s64 retval, offset = 0;
> - static u64 max_khz;
> - u64 mul, div;
> -
> - if (caps->lowest_freq && caps->nominal_freq) {
> - mul = caps->nominal_perf - caps->lowest_perf;
> - div = caps->nominal_freq - caps->lowest_freq;
> - offset = caps->nominal_perf - div64_u64(caps->nominal_freq * mul, div);
> - } else {
> - if (!max_khz)
> - max_khz = cppc_get_dmi_max_khz();
> - mul = caps->highest_perf;
> - div = max_khz;
> - }
> -
> - retval = offset + div64_u64(freq * mul, div);
> - if (retval >= 0)
> - return retval;
> - return 0;
> -}
> -
> static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
> unsigned int target_freq,
> unsigned int relation)
> -
> {
> struct cppc_cpudata *cpu_data = policy->driver_data;
> unsigned int cpu = policy->cpu;
> @@ -389,7 +295,7 @@ static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
> u32 desired_perf;
> int ret = 0;
>
> - desired_perf = cppc_cpufreq_khz_to_perf(cpu_data, target_freq);
> + desired_perf = cppc_khz_to_perf(&cpu_data->perf_caps, target_freq);
> /* Return if it is exactly the same perf */
> if (desired_perf == cpu_data->perf_ctrls.desired_perf)
> return ret;
> @@ -417,7 +323,7 @@ static unsigned int cppc_cpufreq_fast_switch(struct cpufreq_policy *policy,
> u32 desired_perf;
> int ret;
>
> - desired_perf = cppc_cpufreq_khz_to_perf(cpu_data, target_freq);
> + desired_perf = cppc_khz_to_perf(&cpu_data->perf_caps, target_freq);
> cpu_data->perf_ctrls.desired_perf = desired_perf;
> ret = cppc_set_perf(cpu, &cpu_data->perf_ctrls);
>
> @@ -530,7 +436,7 @@ static int cppc_get_cpu_power(struct device *cpu_dev,
> min_step = min_cap / CPPC_EM_CAP_STEP;
> max_step = max_cap / CPPC_EM_CAP_STEP;
>
> - perf_prev = cppc_cpufreq_khz_to_perf(cpu_data, *KHz);
> + perf_prev = cppc_khz_to_perf(perf_caps, *KHz);
> step = perf_prev / perf_step;
>
> if (step > max_step)
> @@ -550,8 +456,8 @@ static int cppc_get_cpu_power(struct device *cpu_dev,
> perf = step * perf_step;
> }
>
> - *KHz = cppc_cpufreq_perf_to_khz(cpu_data, perf);
> - perf_check = cppc_cpufreq_khz_to_perf(cpu_data, *KHz);
> + *KHz = cppc_perf_to_khz(perf_caps, perf);
> + perf_check = cppc_khz_to_perf(perf_caps, *KHz);
> step_check = perf_check / perf_step;
>
> /*
> @@ -561,8 +467,8 @@ static int cppc_get_cpu_power(struct device *cpu_dev,
> */
> while ((*KHz == prev_freq) || (step_check != step)) {
> perf++;
> - *KHz = cppc_cpufreq_perf_to_khz(cpu_data, perf);
> - perf_check = cppc_cpufreq_khz_to_perf(cpu_data, *KHz);
> + *KHz = cppc_perf_to_khz(perf_caps, perf);
> + perf_check = cppc_khz_to_perf(perf_caps, *KHz);
> step_check = perf_check / perf_step;
> }
>
> @@ -591,7 +497,7 @@ static int cppc_get_cpu_cost(struct device *cpu_dev, unsigned long KHz,
> perf_caps = &cpu_data->perf_caps;
> max_cap = arch_scale_cpu_capacity(cpu_dev->id);
>
> - perf_prev = cppc_cpufreq_khz_to_perf(cpu_data, KHz);
> + perf_prev = cppc_khz_to_perf(perf_caps, KHz);
> perf_step = CPPC_EM_CAP_STEP * perf_caps->highest_perf / max_cap;
> step = perf_prev / perf_step;
>
> @@ -643,6 +549,7 @@ static void cppc_cpufreq_register_em(struct cpufreq_policy *policy)
> EM_ADV_DATA_CB(cppc_get_cpu_power, cppc_get_cpu_cost);
>
> cpu_data = policy->driver_data;
> +
> em_dev_register_perf_domain(get_cpu_device(policy->cpu),
> get_perf_level_count(policy), &em_cb,
> cpu_data->shared_cpu_map, 0);
> @@ -724,20 +631,20 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
> * Set min to lowest nonlinear perf to avoid any efficiency penalty (see
> * Section 8.4.7.1.1.5 of ACPI 6.1 spec)
> */
> - policy->min = cppc_cpufreq_perf_to_khz(cpu_data,
> - caps->lowest_nonlinear_perf);
> - policy->max = cppc_cpufreq_perf_to_khz(cpu_data,
> - caps->nominal_perf);
> + policy->min = cppc_perf_to_khz(caps,
> + caps->lowest_nonlinear_perf);
> + policy->max = cppc_perf_to_khz(caps,
> + caps->nominal_perf);
>
> /*
> * Set cpuinfo.min_freq to Lowest to make the full range of performance
> * available if userspace wants to use any perf between lowest & lowest
> * nonlinear perf
> */
> - policy->cpuinfo.min_freq = cppc_cpufreq_perf_to_khz(cpu_data,
> - caps->lowest_perf);
> - policy->cpuinfo.max_freq = cppc_cpufreq_perf_to_khz(cpu_data,
> - caps->nominal_perf);
> + policy->cpuinfo.min_freq = cppc_perf_to_khz(caps,
> + caps->lowest_perf);
> + policy->cpuinfo.max_freq = cppc_perf_to_khz(caps,
> + caps->nominal_perf);
>
> policy->transition_delay_us = cppc_cpufreq_get_transition_delay_us(cpu);
> policy->shared_type = cpu_data->shared_type;
> @@ -773,7 +680,7 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
> boost_supported = true;
>
> /* Set policy->cur to max now. The governors will adjust later. */
> - policy->cur = cppc_cpufreq_perf_to_khz(cpu_data, caps->highest_perf);
> + policy->cur = cppc_perf_to_khz(caps, caps->highest_perf);
> cpu_data->perf_ctrls.desired_perf = caps->highest_perf;
>
> ret = cppc_set_perf(cpu, &cpu_data->perf_ctrls);
> @@ -863,7 +770,7 @@ static unsigned int cppc_cpufreq_get_rate(unsigned int cpu)
> delivered_perf = cppc_perf_from_fbctrs(cpu_data, &fb_ctrs_t0,
> &fb_ctrs_t1);
>
> - return cppc_cpufreq_perf_to_khz(cpu_data, delivered_perf);
> + return cppc_perf_to_khz(&cpu_data->perf_caps, delivered_perf);
> }
>
> static int cppc_cpufreq_set_boost(struct cpufreq_policy *policy, int state)
> @@ -878,11 +785,11 @@ static int cppc_cpufreq_set_boost(struct cpufreq_policy *policy, int state)
> }
>
> if (state)
> - policy->max = cppc_cpufreq_perf_to_khz(cpu_data,
> - caps->highest_perf);
> + policy->max = cppc_perf_to_khz(caps,
> + caps->highest_perf);
> else
> - policy->max = cppc_cpufreq_perf_to_khz(cpu_data,
> - caps->nominal_perf);
> + policy->max = cppc_perf_to_khz(caps,
> + caps->nominal_perf);
> policy->cpuinfo.max_freq = policy->max;
>
> ret = freq_qos_update_request(policy->max_freq_req, policy->max);
> @@ -937,7 +844,7 @@ static unsigned int hisi_cppc_cpufreq_get_rate(unsigned int cpu)
> if (ret < 0)
> return -EIO;
>
> - return cppc_cpufreq_perf_to_khz(cpu_data, desired_perf);
> + return cppc_perf_to_khz(&cpu_data->perf_caps, desired_perf);
> }
>
> static void cppc_check_hisi_workaround(void)
> diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
> index 6126c977ece0..3a0995f8bce8 100644
> --- a/include/acpi/cppc_acpi.h
> +++ b/include/acpi/cppc_acpi.h
> @@ -144,6 +144,8 @@ extern int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls);
> extern int cppc_set_enable(int cpu, bool enable);
> extern int cppc_get_perf_caps(int cpu, struct cppc_perf_caps *caps);
> extern bool cppc_perf_ctrs_in_pcc(void);
> +extern unsigned int cppc_perf_to_khz(struct cppc_perf_caps *caps, unsigned int perf);
> +extern unsigned int cppc_khz_to_perf(struct cppc_perf_caps *caps, unsigned int freq);
> extern bool acpi_cpc_valid(void);
> extern bool cppc_allow_fast_switch(void);
> extern int acpi_get_psd_map(unsigned int cpu, struct cppc_cpudata *cpu_data);
> --
> 2.34.1
>

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