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References: <20231018162540.667646-1-vincent.guittot@linaro.org> <20231018162540.667646-6-vincent.guittot@linaro.org>
In-Reply-To: <20231018162540.667646-6-vincent.guittot@linaro.org>
From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Wed, 18 Oct 2023 19:26:59 +0200
Message-ID: <CAJZ5v0hS7bdUv=-k4ut2Fw0LYfB7Hb1_rro7UOVTRq4=JLNchg@mail.gmail.com>
Subject: Re: [PATCH v3 5/6] cpufreq/cppc: set the frequency used for computing
 the capacity
To:     Vincent Guittot <vincent.guittot@linaro.org>
Cc:     linux@armlinux.org.uk, catalin.marinas@arm.com, will@kernel.org,
        paul.walmsley@sifive.com, palmer@dabbelt.com,
        aou@eecs.berkeley.edu, sudeep.holla@arm.com,
        gregkh@linuxfoundation.org, rafael@kernel.org, mingo@redhat.com,
        peterz@infradead.org, juri.lelli@redhat.com,
        dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com,
        mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com,
        viresh.kumar@linaro.org, lenb@kernel.org, robert.moore@intel.com,
        lukasz.luba@arm.com, ionela.voinescu@arm.com,
        pierre.gondois@arm.com, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
        linux-pm@vger.kernel.org, linux-acpi@vger.kernel.org,
        acpica-devel@lists.linuxfoundation.org, conor.dooley@microchip.com,
        suagrfillet@gmail.com, ajones@ventanamicro.com, lftan@kernel.org
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On Wed, Oct 18, 2023 at 6:25 PM Vincent Guittot
<vincent.guittot@linaro.org> 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@linaro.org>

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

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

> ---
>  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
>