[PATCH 11/16] cpufreq: intel_pstate: Add update_util callback to pstate_funcs

From: Rafael J. Wysocki
Date: Mon Mar 27 2017 - 18:46:18 EST


From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

Avoid using extra function pointers during P-state selection by
dropping the get_target_pstate member from struct pstate_funcs,
adding a new update_util callback to it (to be registered with
the CPU scheduler as the utilization update callback in the active
mode) and reworking the utilization update callback routines to
invoke specific P-state selection functions directly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
drivers/cpufreq/intel_pstate.c | 81 +++++++++++++++++++++--------------------
1 file changed, 43 insertions(+), 38 deletions(-)

Index: linux-pm/drivers/cpufreq/intel_pstate.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/intel_pstate.c
+++ linux-pm/drivers/cpufreq/intel_pstate.c
@@ -311,7 +311,7 @@ struct pstate_adjust_policy {
* @get_scaling: Callback to get frequency scaling factor
* @get_val: Callback to convert P state to actual MSR write value
* @get_vid: Callback to get VID data for Atom platforms
- * @get_target_pstate: Callback to a function to calculate next P state to use
+ * @update_util: Active mode utilization update callback.
*
* Core and Atom CPU models have different way to get P State limits. This
* structure is used to store those callbacks.
@@ -324,7 +324,8 @@ struct pstate_funcs {
int (*get_scaling)(void);
u64 (*get_val)(struct cpudata*, int pstate);
void (*get_vid)(struct cpudata *);
- int32_t (*get_target_pstate)(struct cpudata *);
+ void (*update_util)(struct update_util_data *data, u64 time,
+ unsigned int flags);
};

/**
@@ -335,9 +336,6 @@ struct cpu_defaults {
struct pstate_funcs funcs;
};

-static inline int32_t get_target_pstate_use_performance(struct cpudata *cpu);
-static inline int32_t get_target_pstate_use_cpu_load(struct cpudata *cpu);
-
static struct pstate_funcs pstate_funcs __read_mostly;
static struct pstate_adjust_policy pid_params __read_mostly = {
.sample_rate_ms = 10,
@@ -1510,6 +1508,11 @@ static int knl_get_turbo_pstate(void)
return ret;
}

+static void intel_pstate_update_util_pid(struct update_util_data *data,
+ u64 time, unsigned int flags);
+static void intel_pstate_update_util(struct update_util_data *data, u64 time,
+ unsigned int flags);
+
static struct cpu_defaults core_params = {
.funcs = {
.get_max = core_get_max_pstate,
@@ -1518,7 +1521,7 @@ static struct cpu_defaults core_params =
.get_turbo = core_get_turbo_pstate,
.get_scaling = core_get_scaling,
.get_val = core_get_val,
- .get_target_pstate = get_target_pstate_use_performance,
+ .update_util = intel_pstate_update_util_pid,
},
};

@@ -1531,7 +1534,7 @@ static const struct cpu_defaults silverm
.get_val = atom_get_val,
.get_scaling = silvermont_get_scaling,
.get_vid = atom_get_vid,
- .get_target_pstate = get_target_pstate_use_cpu_load,
+ .update_util = intel_pstate_update_util,
},
};

@@ -1544,7 +1547,7 @@ static const struct cpu_defaults airmont
.get_val = atom_get_val,
.get_scaling = airmont_get_scaling,
.get_vid = atom_get_vid,
- .get_target_pstate = get_target_pstate_use_cpu_load,
+ .update_util = intel_pstate_update_util,
},
};

@@ -1556,7 +1559,7 @@ static const struct cpu_defaults knl_par
.get_turbo = knl_get_turbo_pstate,
.get_scaling = core_get_scaling,
.get_val = core_get_val,
- .get_target_pstate = get_target_pstate_use_performance,
+ .update_util = intel_pstate_update_util_pid,
},
};

@@ -1568,7 +1571,7 @@ static const struct cpu_defaults bxt_par
.get_turbo = core_get_turbo_pstate,
.get_scaling = core_get_scaling,
.get_val = core_get_val,
- .get_target_pstate = get_target_pstate_use_cpu_load,
+ .update_util = intel_pstate_update_util,
},
};

@@ -1704,6 +1707,9 @@ static inline int32_t get_target_pstate_
int32_t busy_frac, boost;
int target, avg_pstate;

+ if (cpu->policy == CPUFREQ_POLICY_PERFORMANCE)
+ return cpu->pstate.turbo_pstate;
+
busy_frac = div_fp(sample->mperf, sample->tsc);

boost = cpu->iowait_boost;
@@ -1740,6 +1746,9 @@ static inline int32_t get_target_pstate_
int32_t perf_scaled, max_pstate, current_pstate, sample_ratio;
u64 duration_ns;

+ if (cpu->policy == CPUFREQ_POLICY_PERFORMANCE)
+ return cpu->pstate.turbo_pstate;
+
/*
* perf_scaled is the ratio of the average P-state during the last
* sampling period to the P-state requested last time (in percent).
@@ -1790,16 +1799,11 @@ static void intel_pstate_update_pstate(s
wrmsrl(MSR_IA32_PERF_CTL, pstate_funcs.get_val(cpu, pstate));
}

-static void intel_pstate_adjust_busy_pstate(struct cpudata *cpu)
+static void intel_pstate_adjust_pstate(struct cpudata *cpu, int target_pstate)
{
- int from, target_pstate;
+ int from = cpu->pstate.current_pstate;
struct sample *sample;

- from = cpu->pstate.current_pstate;
-
- target_pstate = cpu->policy == CPUFREQ_POLICY_PERFORMANCE ?
- cpu->pstate.turbo_pstate : pstate_funcs.get_target_pstate(cpu);
-
update_turbo_state();

target_pstate = intel_pstate_prepare_request(cpu, target_pstate);
@@ -1837,8 +1841,12 @@ static void intel_pstate_update_util_pid
if ((s64)delta_ns < pid_params.sample_rate_ns)
return;

- if (intel_pstate_sample(cpu, time))
- intel_pstate_adjust_busy_pstate(cpu);
+ if (intel_pstate_sample(cpu, time)) {
+ int target_pstate;
+
+ target_pstate = get_target_pstate_use_performance(cpu);
+ intel_pstate_adjust_pstate(cpu, target_pstate);
+ }
}

static void intel_pstate_update_util(struct update_util_data *data, u64 time,
@@ -1860,13 +1868,13 @@ static void intel_pstate_update_util(str
if ((s64)delta_ns < INTEL_PSTATE_DEFAULT_SAMPLING_INTERVAL)
return;

- if (intel_pstate_sample(cpu, time))
- intel_pstate_adjust_busy_pstate(cpu);
-}
+ if (intel_pstate_sample(cpu, time)) {
+ int target_pstate;

-/* Utilization update callback to register in the active mode. */
-static void (*update_util_cb)(struct update_util_data *data, u64 time,
- unsigned int flags) = intel_pstate_update_util;
+ target_pstate = get_target_pstate_use_cpu_load(cpu);
+ intel_pstate_adjust_pstate(cpu, target_pstate);
+ }
+}

#define ICPU(model, policy) \
{ X86_VENDOR_INTEL, 6, model, X86_FEATURE_APERFMPERF,\
@@ -1938,7 +1946,7 @@ static int intel_pstate_init_cpu(unsigne
intel_pstate_disable_ee(cpunum);

intel_pstate_hwp_enable(cpu);
- } else if (pstate_funcs.get_target_pstate == get_target_pstate_use_performance) {
+ } else if (pstate_funcs.update_util == intel_pstate_update_util_pid) {
intel_pstate_pid_reset(cpu);
}

@@ -1965,7 +1973,8 @@ static void intel_pstate_set_update_util

/* Prevent intel_pstate_update_util() from using stale data. */
cpu->sample.time = 0;
- cpufreq_add_update_util_hook(cpu_num, &cpu->update_util, update_util_cb);
+ cpufreq_add_update_util_hook(cpu_num, &cpu->update_util,
+ pstate_funcs.update_util);
cpu->update_util_set = true;
}

@@ -2318,7 +2327,7 @@ static int intel_pstate_register_driver(
global.min_perf_pct = min_perf_pct_min();

if (intel_pstate_driver == &intel_pstate && !hwp_active &&
- pstate_funcs.get_target_pstate != get_target_pstate_use_cpu_load)
+ pstate_funcs.update_util == intel_pstate_update_util_pid)
intel_pstate_debug_expose_params();

return 0;
@@ -2329,8 +2338,8 @@ static int intel_pstate_unregister_drive
if (hwp_active)
return -EBUSY;

- if (intel_pstate_driver == &intel_pstate && !hwp_active &&
- pstate_funcs.get_target_pstate != get_target_pstate_use_cpu_load)
+ if (intel_pstate_driver == &intel_pstate &&
+ pstate_funcs.update_util == intel_pstate_update_util_pid)
intel_pstate_debug_hide_params();

cpufreq_unregister_driver(intel_pstate_driver);
@@ -2409,8 +2418,7 @@ static void intel_pstate_use_acpi_profil
case PM_APPLIANCE_PC:
case PM_DESKTOP:
case PM_WORKSTATION:
- pstate_funcs.get_target_pstate =
- get_target_pstate_use_cpu_load;
+ pstate_funcs.update_util = intel_pstate_update_util;
}
}
#else
@@ -2428,12 +2436,9 @@ static void __init copy_cpu_funcs(struct
pstate_funcs.get_scaling = funcs->get_scaling;
pstate_funcs.get_val = funcs->get_val;
pstate_funcs.get_vid = funcs->get_vid;
- pstate_funcs.get_target_pstate = funcs->get_target_pstate;
+ pstate_funcs.update_util = funcs->update_util;

intel_pstate_use_acpi_profile();
-
- if (pstate_funcs.get_target_pstate == get_target_pstate_use_performance)
- update_util_cb = intel_pstate_update_util_pid;
}

#ifdef CONFIG_ACPI
@@ -2578,11 +2583,11 @@ static int __init intel_pstate_init(void
if (x86_match_cpu(hwp_support_ids)) {
copy_cpu_funcs(&core_params.funcs);
if (no_hwp) {
- update_util_cb = intel_pstate_update_util;
+ pstate_funcs.update_util = intel_pstate_update_util;
} else {
hwp_active++;
intel_pstate.attr = hwp_cpufreq_attrs;
- update_util_cb = intel_pstate_update_util_hwp;
+ pstate_funcs.update_util = intel_pstate_update_util_hwp;
goto hwp_cpu_matched;
}
} else {