RE: [PATCH V10 3/7] cpufreq: amd-pstate: Enable amd-pstate preferred core supporting.

From: Meng, Li (Jassmine)
Date: Mon Nov 06 2023 - 03:15:42 EST

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In reply to: Yuan, Perry: "RE: [PATCH V10 3/7] cpufreq: amd-pstate: Enable amd-pstate preferred core supporting."
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[AMD Official Use Only - General]

Hi perry：

> -----Original Message-----
> From: Yuan, Perry <Perry.Yuan@xxxxxxx>
> Sent: Thursday, November 2, 2023 5:06 PM
> To: Meng, Li (Jassmine) <Li.Meng@xxxxxxx>; Rafael J . Wysocki
> <rafael.j.wysocki@xxxxxxxxx>; Huang, Ray <Ray.Huang@xxxxxxx>
> Cc: linux-pm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> x86@xxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; Shuah Khan
> <skhan@xxxxxxxxxxxxxxxxxxx>; linux-kselftest@xxxxxxxxxxxxxxx; Fontenot,
> Nathan <Nathan.Fontenot@xxxxxxx>; Sharma, Deepak
> <Deepak.Sharma@xxxxxxx>; Deucher, Alexander
> <Alexander.Deucher@xxxxxxx>; Limonciello, Mario
> <Mario.Limonciello@xxxxxxx>; Huang, Shimmer
> <Shimmer.Huang@xxxxxxx>; Du, Xiaojian <Xiaojian.Du@xxxxxxx>; Viresh
> Kumar <viresh.kumar@xxxxxxxxxx>; Borislav Petkov <bp@xxxxxxxxx>;
> Oleksandr Natalenko <oleksandr@xxxxxxxxxxxxxx>; Karny, Wyes
> <Wyes.Karny@xxxxxxx>
> Subject: RE: [PATCH V10 3/7] cpufreq: amd-pstate: Enable amd-pstate
> preferred core supporting.
>
> [AMD Official Use Only - General]
>
> Hi meng Li,
>
>
> > -----Original Message-----
> > From: Meng, Li (Jassmine) <Li.Meng@xxxxxxx>
> > Sent: Monday, October 30, 2023 2:34 PM
> > To: Rafael J . Wysocki <rafael.j.wysocki@xxxxxxxxx>; Huang, Ray
> > <Ray.Huang@xxxxxxx>
> > Cc: linux-pm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> > x86@xxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; Shuah Khan
> > <skhan@xxxxxxxxxxxxxxxxxxx>; linux- kselftest@xxxxxxxxxxxxxxx;
> > Fontenot, Nathan <Nathan.Fontenot@xxxxxxx>; Sharma, Deepak
> > <Deepak.Sharma@xxxxxxx>; Deucher, Alexander
> > <Alexander.Deucher@xxxxxxx>; Limonciello, Mario
> > <Mario.Limonciello@xxxxxxx>; Huang, Shimmer
> <Shimmer.Huang@xxxxxxx>;
> > Yuan, Perry <Perry.Yuan@xxxxxxx>; Du, Xiaojian
> <Xiaojian.Du@xxxxxxx>;
> > Viresh Kumar <viresh.kumar@xxxxxxxxxx>; Borislav Petkov
> > <bp@xxxxxxxxx>; Oleksandr Natalenko <oleksandr@xxxxxxxxxxxxxx>;
> Meng,
> > Li (Jassmine) <Li.Meng@xxxxxxx>; Karny, Wyes <Wyes.Karny@xxxxxxx>
> > Subject: [PATCH V10 3/7] cpufreq: amd-pstate: Enable amd-pstate
> > preferred core supporting.
> >
> > amd-pstate driver utilizes the functions and data structures provided
> > by the ITMT architecture to enable the scheduler to favor scheduling
> > on cores which can be get a higher frequency with lower voltage. We
> > call it amd-pstate preferrred core.
> >
> > Here sched_set_itmt_core_prio() is called to set priorities and
> > sched_set_itmt_support() is called to enable ITMT feature.
> > amd-pstate driver uses the highest performance value to indicate the
> > priority of CPU. The higher value has a higher priority.
> >
> > The initial core rankings are set up by amd-pstate when the system boots.
> >
> > Add a variable hw_prefcore in cpudata structure. It will check if the
> > processor and power firmware support preferred core feature.
> >
> > Add one new early parameter `disable` to allow user to disable the
> > preferred core.
> >
> > Only when hardware supports preferred core and user set `enabled` in
> > early parameter, amd pstate driver supports preferred core featue.
> >
> > Tested-by: Oleksandr Natalenko <oleksandr@xxxxxxxxxxxxxx>
> > Reviewed-by: Huang Rui <ray.huang@xxxxxxx>
> > Reviewed-by: Wyes Karny <wyes.karny@xxxxxxx>
> > Reviewed-by: Mario Limonciello <mario.limonciello@xxxxxxx>
> > Co-developed-by: Perry Yuan <Perry.Yuan@xxxxxxx>
> > Signed-off-by: Perry Yuan <Perry.Yuan@xxxxxxx>
> > Signed-off-by: Meng Li <li.meng@xxxxxxx>
> > ---
> > drivers/cpufreq/amd-pstate.c | 141
> > +++++++++++++++++++++++++++++++----
> > include/linux/amd-pstate.h | 4 +
> > 2 files changed, 129 insertions(+), 16 deletions(-)
> >
> > diff --git a/drivers/cpufreq/amd-pstate.c
> > b/drivers/cpufreq/amd-pstate.c index 9a1e194d5cf8..2033e5e70017 100644
> > --- a/drivers/cpufreq/amd-pstate.c
> > +++ b/drivers/cpufreq/amd-pstate.c
> > @@ -37,6 +37,7 @@
> > #include <linux/uaccess.h>
> > #include <linux/static_call.h>
> > #include <linux/amd-pstate.h>
> > +#include <linux/topology.h>
> >
> > #include <acpi/processor.h>
> > #include <acpi/cppc_acpi.h>
> > @@ -49,6 +50,7 @@
> >
> > #define AMD_PSTATE_TRANSITION_LATENCY 20000
> > #define AMD_PSTATE_TRANSITION_DELAY 1000
> > +#define AMD_PSTATE_PREFCORE_THRESHOLD 166
> >
> > /*
> > * TODO: We need more time to fine tune processors with shared memory
> > solution @@ -64,6 +66,7 @@ static struct cpufreq_driver
> > amd_pstate_driver; static struct cpufreq_driver amd_pstate_epp_driver;
> > static int cppc_state = AMD_PSTATE_UNDEFINED; static bool
> > cppc_enabled;
> > +static bool amd_pstate_prefcore = true;
> >
> > /*
> > * AMD Energy Preference Performance (EPP) @@ -290,23 +293,21 @@
> > static inline int amd_pstate_enable(bool enable) static int
> > pstate_init_perf(struct amd_cpudata *cpudata) {
> > u64 cap1;
> > - u32 highest_perf;
> >
> > int ret = rdmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_CAP1,
> > &cap1);
> > if (ret)
> > return ret;
> >
> > - /*
> > - * TODO: Introduce AMD specific power feature.
> > - *
> > - * CPPC entry doesn't indicate the highest performance in some ASICs.
> > + /* For platforms that do not support the preferred core feature, the
> > + * highest_pef may be configured with 166 or 255, to avoid max
> > frequency
> > + * calculated wrongly. we take the AMD_CPPC_HIGHEST_PERF(cap1)
> > value as
> > + * the default max perf.
> > */
> > - highest_perf = amd_get_highest_perf();
> > - if (highest_perf > AMD_CPPC_HIGHEST_PERF(cap1))
> > - highest_perf = AMD_CPPC_HIGHEST_PERF(cap1);
> > -
> > - WRITE_ONCE(cpudata->highest_perf, highest_perf);
> > + if (cpudata->hw_prefcore)
> > + WRITE_ONCE(cpudata->highest_perf,
> > AMD_PSTATE_PREFCORE_THRESHOLD);
> > + else
> > + WRITE_ONCE(cpudata->highest_perf,
> > AMD_CPPC_HIGHEST_PERF(cap1));
> >
> > WRITE_ONCE(cpudata->nominal_perf,
> AMD_CPPC_NOMINAL_PERF(cap1));
> > WRITE_ONCE(cpudata->lowest_nonlinear_perf,
> > AMD_CPPC_LOWNONLIN_PERF(cap1)); @@ -318,17 +319,15 @@ static int
> > pstate_init_perf(struct amd_cpudata *cpudata) static int
> > cppc_init_perf(struct amd_cpudata *cpudata) {
> > struct cppc_perf_caps cppc_perf;
> > - u32 highest_perf;
> >
> > int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);
> > if (ret)
> > return ret;
> >
> > - highest_perf = amd_get_highest_perf();
> > - if (highest_perf > cppc_perf.highest_perf)
> > - highest_perf = cppc_perf.highest_perf;
> > -
> > - WRITE_ONCE(cpudata->highest_perf, highest_perf);
> > + if (cpudata->hw_prefcore)
> > + WRITE_ONCE(cpudata->highest_perf,
> > AMD_PSTATE_PREFCORE_THRESHOLD);
> > + else
> > + WRITE_ONCE(cpudata->highest_perf,
> > cppc_perf.highest_perf);
> >
> > WRITE_ONCE(cpudata->nominal_perf, cppc_perf.nominal_perf);
> > WRITE_ONCE(cpudata->lowest_nonlinear_perf,
> > @@ -676,6 +675,80 @@ static void amd_perf_ctl_reset(unsigned int cpu)
> > wrmsrl_on_cpu(cpu, MSR_AMD_PERF_CTL, 0); }
> >
> > +/*
> > + * Set amd-pstate preferred core enable can't be done directly from
> > +cpufreq callbacks
> > + * due to locking, so queue the work for later.
> > + */
> > +static void amd_pstste_sched_prefcore_workfn(struct work_struct
> > +*work) {
> > + sched_set_itmt_support();
> > +}
> > +static DECLARE_WORK(sched_prefcore_work,
> > +amd_pstste_sched_prefcore_workfn);
> > +
> > +/*
> > + * Get the highest performance register value.
> > + * @cpu: CPU from which to get highest performance.
> > + * @highest_perf: Return address.
> > + *
> > + * Return: 0 for success, -EIO otherwise.
> > + */
> > +static int amd_pstate_get_highest_perf(int cpu, u32 *highest_perf) {
> > + int ret;
> > +
> > + if (boot_cpu_has(X86_FEATURE_CPPC)) {
> > + u64 cap1;
> > +
> > + ret = rdmsrl_safe_on_cpu(cpu, MSR_AMD_CPPC_CAP1,
> > &cap1);
> > + if (ret)
> > + return ret;
> > + WRITE_ONCE(*highest_perf,
> > AMD_CPPC_HIGHEST_PERF(cap1));
> > + } else {
> > + u64 cppc_highest_perf;
> > +
> > + ret = cppc_get_highest_perf(cpu, &cppc_highest_perf);
> > + if (ret)
> > + return ret;
> > + WRITE_ONCE(*highest_perf, cppc_highest_perf);
> > + }
> > +
> > + return (ret);
> > +}
> > +
> > +#define CPPC_MAX_PERF U8_MAX
> > +
> > +static void amd_pstate_init_prefcore(struct amd_cpudata *cpudata) {
> > + int ret, prio;
> > + u32 highest_perf;
> > +
> > + ret = amd_pstate_get_highest_perf(cpudata->cpu, &highest_perf);
> > + if (ret)
> > + return;
> > +
> > + cpudata->hw_prefcore = true;
> > + /* check if CPPC preferred core feature is enabled*/
> > + if (highest_perf < CPPC_MAX_PERF)
> > + prio = (int)highest_perf;
> > + else {
> > + pr_debug("AMD CPPC preferred core is unsupported!\n");
> > + cpudata->hw_prefcore = false;
> > + return;
> > + }
> > +
> > + if (!amd_pstate_prefcore)
> > + return;
>
> Move the feature state check to earlier before you call
> amd_pstate_get_highest_perf().
> If the feature is not enabled, you have no need to read highest perf.
>
[Meng, Li (Jassmine)] I need to set hw_prefcore by highest_perf.
Therefore, the judgment condition “amd_pstate_prefcore” cannot be moved forward.
>
> > +
> > + /*
> > + * The priorities can be set regardless of whether or not
> > + * sched_set_itmt_support(true) has been called and it is valid to
> > + * update them at any time after it has been called.
> > + */
> > + sched_set_itmt_core_prio(prio, cpudata->cpu);
> > +
> > + schedule_work(&sched_prefcore_work);
> > +}
> > +
> > static int amd_pstate_cpu_init(struct cpufreq_policy *policy) {
> > int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq,
> > ret; @@ -697,6 +770,8 @@ static int amd_pstate_cpu_init(struct
> > cpufreq_policy
> > *policy)
> >
> > cpudata->cpu = policy->cpu;
> >
> > + amd_pstate_init_prefcore(cpudata);
> > +
> > ret = amd_pstate_init_perf(cpudata);
> > if (ret)
> > goto free_cpudata1;
> > @@ -845,6 +920,17 @@ static ssize_t
> > show_amd_pstate_highest_perf(struct
> > cpufreq_policy *policy,
> > return sysfs_emit(buf, "%u\n", perf); }
> >
> > +static ssize_t show_amd_pstate_hw_prefcore(struct cpufreq_policy
> *policy,
> > + char *buf) {
> > + bool hw_prefcore;
> > + struct amd_cpudata *cpudata = policy->driver_data;
> > +
> > + hw_prefcore = READ_ONCE(cpudata->hw_prefcore);
> > +
> > + return sysfs_emit(buf, "%s\n", hw_prefcore ? "supported" :
> > +"unsupported"); }
>
> Replace the string with str_enabled_disabled() function that is defined as
> below.
>
> include/linux/string_helpers.h
>
> static inline const char *str_enabled_disabled(bool v) {
> return v ? "enabled" : "disabled"; }
>
> Perry.
>
> > +
> > static ssize_t show_energy_performance_available_preferences(
> > struct cpufreq_policy *policy, char
> > *buf) { @@ -1037,18 +1123,27 @@ static ssize_t status_store(struct
> > device *a, struct device_attribute *b,
> > return ret < 0 ? ret : count;
> > }
> >
> > +static ssize_t prefcore_show(struct device *dev,
> > + struct device_attribute *attr, char *buf) {
> > + return sysfs_emit(buf, "%s\n", amd_pstate_prefcore ? "enabled" :
> > +"disabled"); }
>
> Replace the string with str_enabled_disabled() function that is defined as
> below.
>
> include/linux/string_helpers.h
>
>
> > +
> > cpufreq_freq_attr_ro(amd_pstate_max_freq);
> > cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
> >
> > cpufreq_freq_attr_ro(amd_pstate_highest_perf);
> > +cpufreq_freq_attr_ro(amd_pstate_hw_prefcore);
> > cpufreq_freq_attr_rw(energy_performance_preference);
> > cpufreq_freq_attr_ro(energy_performance_available_preferences);
> > static DEVICE_ATTR_RW(status);
> > +static DEVICE_ATTR_RO(prefcore);
> >
> > static struct freq_attr *amd_pstate_attr[] = {
> > &amd_pstate_max_freq,
> > &amd_pstate_lowest_nonlinear_freq,
> > &amd_pstate_highest_perf,
> > + &amd_pstate_hw_prefcore,
> > NULL,
> > };
> >
> > @@ -1056,6 +1151,7 @@ static struct freq_attr *amd_pstate_epp_attr[] =
> {
> > &amd_pstate_max_freq,
> > &amd_pstate_lowest_nonlinear_freq,
> > &amd_pstate_highest_perf,
> > + &amd_pstate_hw_prefcore,
> > &energy_performance_preference,
> > &energy_performance_available_preferences,
> > NULL,
> > @@ -1063,6 +1159,7 @@ static struct freq_attr *amd_pstate_epp_attr[] =
> > {
> >
> > static struct attribute *pstate_global_attributes[] = {
> > &dev_attr_status.attr,
> > + &dev_attr_prefcore.attr,
> > NULL
> > };
> >
> > @@ -1114,6 +1211,8 @@ static int amd_pstate_epp_cpu_init(struct
> > cpufreq_policy *policy)
> > cpudata->cpu = policy->cpu;
> > cpudata->epp_policy = 0;
> >
> > + amd_pstate_init_prefcore(cpudata);
> > +
> > ret = amd_pstate_init_perf(cpudata);
> > if (ret)
> > goto free_cpudata1;
> > @@ -1527,7 +1626,17 @@ static int __init amd_pstate_param(char *str)
> >
> > return amd_pstate_set_driver(mode_idx); }
> > +
> > +static int __init amd_prefcore_param(char *str) {
> > + if (!strcmp(str, "disable"))
> > + amd_pstate_prefcore = false;
> > +
> > + return 0;
> > +}
> > +
> > early_param("amd_pstate", amd_pstate_param);
> > +early_param("amd_prefcore", amd_prefcore_param);
> >
> > MODULE_AUTHOR("Huang Rui <ray.huang@xxxxxxx>");
> > MODULE_DESCRIPTION("AMD Processor P-state Frequency Driver"); diff
> > --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h index
> > 446394f84606..87e140e9e6db 100644
> > --- a/include/linux/amd-pstate.h
> > +++ b/include/linux/amd-pstate.h
> > @@ -52,6 +52,9 @@ struct amd_aperf_mperf {
> > * @prev: Last Aperf/Mperf/tsc count value read from register
> > * @freq: current cpu frequency value
> > * @boost_supported: check whether the Processor or SBIOS supports
> > boost mode
> > + * @hw_prefcore: check whether HW supports preferred core featue.
> > + * Only when hw_prefcore and early prefcore param are true,
> > + * AMD P-State driver supports preferred core featue.
> > * @epp_policy: Last saved policy used to set energy-performance
> preference
> > * @epp_cached: Cached CPPC energy-performance preference value
> > * @policy: Cpufreq policy value
> > @@ -81,6 +84,7 @@ struct amd_cpudata {
> >
> > u64 freq;
> > bool boost_supported;
> > + bool hw_prefcore;
> >
> > /* EPP feature related attributes*/
> > s16 epp_policy;
> > --
> > 2.34.1
>

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In reply to: Yuan, Perry: "RE: [PATCH V10 3/7] cpufreq: amd-pstate: Enable amd-pstate preferred core supporting."
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