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Merge branch 'pm-cpuidle' 

* pm-cpuidle:
  cpuidle: menu: Avoid computations when result will be discarded
  cpuidle: menu: Drop redundant comparison
  cpuidle: menu: Simplify checks related to the polling state
  cpuidle: poll_state: Revise loop termination condition
  cpuidle: menu: Move the latency_req == 0 special case check
  cpuidle: menu: Avoid computations for very close timers
  cpuidle: menu: Do not update last_state_idx in menu_select()
  cpuidle: menu: Get rid of first_idx from menu_select()
  cpuidle: menu: Compute first_idx when latency_req is known
  cpuidle: menu: Fix wakeup statistics updates for polling state
  cpuidle: menu: Replace data->predicted_us with local variable
  cpuidle: enter_state: Don't needlessly calculate diff time
  cpuidle: Remove unnecessary wrapper cpuidle_get_last_residency()
  intel_idle: Get rid of custom ICPU() macro
This commit is contained in:
Rafael J. Wysocki 2018-10-18 12:26:00 +02:00
parent e5089c2c73 f1c8e410cd
commit 41fd838cda
6 changed files with 117 additions and 109 deletions
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16
drivers/cpuidle/cpuidle.c
View File

@ -247,17 +247,17 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
if (!cpuidle_state_is_coupled(drv, index))
local_irq_enable();
diff = ktime_us_delta(time_end, time_start);
if (diff > INT_MAX)
diff = INT_MAX;
dev->last_residency = (int) diff;
if (entered_state >= 0) {
/* Update cpuidle counters */
/* This can be moved to within driver enter routine
/*
* Update cpuidle counters
* This can be moved to within driver enter routine,
* but that results in multiple copies of same code.
*/
diff = ktime_us_delta(time_end, time_start);
if (diff > INT_MAX)
diff = INT_MAX;
dev->last_residency = (int)diff;
dev->states_usage[entered_state].time += dev->last_residency;
dev->states_usage[entered_state].usage++;
} else {

2
drivers/cpuidle/governors/ladder.c
View File

@ -80,7 +80,7 @@ static int ladder_select_state(struct cpuidle_driver *drv,
last_state = &ldev->states[last_idx];
last_residency = cpuidle_get_last_residency(dev) - drv->states[last_idx].exit_latency;
last_residency = dev->last_residency - drv->states[last_idx].exit_latency;
/* consider promotion */
if (last_idx < drv->state_count - 1 &&

114
drivers/cpuidle/governors/menu.c
View File

@ -124,7 +124,6 @@ struct menu_device {
int tick_wakeup;
unsigned int next_timer_us;
unsigned int predicted_us;
unsigned int bucket;
unsigned int correction_factor[BUCKETS];
unsigned int intervals[INTERVALS];
@ -197,10 +196,11 @@ static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev);
* of points is below a threshold. If it is... then use the
* average of these 8 points as the estimated value.
*/
static unsigned int get_typical_interval(struct menu_device *data)
static unsigned int get_typical_interval(struct menu_device *data,
unsigned int predicted_us)
{
int i, divisor;
unsigned int max, thresh, avg;
unsigned int min, max, thresh, avg;
uint64_t sum, variance;
thresh = UINT_MAX; /* Discard outliers above this value */
@ -208,6 +208,7 @@ static unsigned int get_typical_interval(struct menu_device *data)
again:
/* First calculate the average of past intervals */
min = UINT_MAX;
max = 0;
sum = 0;
divisor = 0;
@ -218,8 +219,19 @@ static unsigned int get_typical_interval(struct menu_device *data)
divisor++;
if (value > max)
max = value;
if (value < min)
min = value;
}
}
/*
* If the result of the computation is going to be discarded anyway,
* avoid the computation altogether.
*/
if (min >= predicted_us)
return UINT_MAX;
if (divisor == INTERVALS)
avg = sum >> INTERVAL_SHIFT;
else
@ -286,10 +298,9 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
struct menu_device *data = this_cpu_ptr(&menu_devices);
int latency_req = cpuidle_governor_latency_req(dev->cpu);
int i;
int first_idx;
int idx;
unsigned int interactivity_req;
unsigned int expected_interval;
unsigned int predicted_us;
unsigned long nr_iowaiters, cpu_load;
ktime_t delta_next;
@ -298,50 +309,36 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
data->needs_update = 0;
}
/* Special case when user has set very strict latency requirement */
if (unlikely(latency_req == 0)) {
*stop_tick = false;
return 0;
}
/* determine the expected residency time, round up */
data->next_timer_us = ktime_to_us(tick_nohz_get_sleep_length(&delta_next));
get_iowait_load(&nr_iowaiters, &cpu_load);
data->bucket = which_bucket(data->next_timer_us, nr_iowaiters);
if (unlikely(drv->state_count <= 1 || latency_req == 0) ||
((data->next_timer_us < drv->states[1].target_residency ||
latency_req < drv->states[1].exit_latency) &&
!drv->states[0].disabled && !dev->states_usage[0].disable)) {
/*
* In this case state[0] will be used no matter what, so return
* it right away and keep the tick running.
*/
*stop_tick = false;
return 0;
}
/*
* Force the result of multiplication to be 64 bits even if both
* operands are 32 bits.
* Make sure to round up for half microseconds.
*/
data->predicted_us = DIV_ROUND_CLOSEST_ULL((uint64_t)data->next_timer_us *
predicted_us = DIV_ROUND_CLOSEST_ULL((uint64_t)data->next_timer_us *
data->correction_factor[data->bucket],
RESOLUTION * DECAY);
expected_interval = get_typical_interval(data);
expected_interval = min(expected_interval, data->next_timer_us);
first_idx = 0;
if (drv->states[0].flags & CPUIDLE_FLAG_POLLING) {
struct cpuidle_state *s = &drv->states[1];
unsigned int polling_threshold;
/*
* Default to a physical idle state, not to busy polling, unless
* a timer is going to trigger really really soon.
*/
polling_threshold = max_t(unsigned int, 20, s->target_residency);
if (data->next_timer_us > polling_threshold &&
latency_req > s->exit_latency && !s->disabled &&
!dev->states_usage[1].disable)
first_idx = 1;
}
/*
* Use the lowest expected idle interval to pick the idle state.
*/
data->predicted_us = min(data->predicted_us, expected_interval);
predicted_us = min(predicted_us, get_typical_interval(data, predicted_us));
if (tick_nohz_tick_stopped()) {
/*
@ -352,34 +349,46 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
* the known time till the closest timer event for the idle
* state selection.
*/
if (data->predicted_us < TICK_USEC)
data->predicted_us = ktime_to_us(delta_next);
if (predicted_us < TICK_USEC)
predicted_us = ktime_to_us(delta_next);
} else {
/*
* Use the performance multiplier and the user-configurable
* latency_req to determine the maximum exit latency.
*/
interactivity_req = data->predicted_us / performance_multiplier(nr_iowaiters, cpu_load);
interactivity_req = predicted_us / performance_multiplier(nr_iowaiters, cpu_load);
if (latency_req > interactivity_req)
latency_req = interactivity_req;
}
expected_interval = data->predicted_us;
/*
* Find the idle state with the lowest power while satisfying
* our constraints.
*/
idx = -1;
for (i = first_idx; i < drv->state_count; i++) {
for (i = 0; i < drv->state_count; i++) {
struct cpuidle_state *s = &drv->states[i];
struct cpuidle_state_usage *su = &dev->states_usage[i];
if (s->disabled || su->disable)
continue;
if (idx == -1)
idx = i; /* first enabled state */
if (s->target_residency > data->predicted_us) {
if (data->predicted_us < TICK_USEC)
if (s->target_residency > predicted_us) {
/*
* Use a physical idle state, not busy polling, unless
* a timer is going to trigger soon enough.
*/
if ((drv->states[idx].flags & CPUIDLE_FLAG_POLLING) &&
s->exit_latency <= latency_req &&
s->target_residency <= data->next_timer_us) {
predicted_us = s->target_residency;
idx = i;
break;
}
if (predicted_us < TICK_USEC)
break;
if (!tick_nohz_tick_stopped()) {
@ -389,7 +398,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
* tick in that case and let the governor run
* again in the next iteration of the loop.
*/
expected_interval = drv->states[idx].target_residency;
predicted_us = drv->states[idx].target_residency;
break;
}
@ -403,7 +412,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
s->target_residency <= ktime_to_us(delta_next))
idx = i;
goto out;
return idx;
}
if (s->exit_latency > latency_req) {
/*
@ -412,7 +421,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
* expected idle duration so that the tick is retained
* as long as that target residency is low enough.
*/
expected_interval = drv->states[idx].target_residency;
predicted_us = drv->states[idx].target_residency;
break;
}
idx = i;
@ -426,7 +435,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
* expected idle duration is shorter than the tick period length.
*/
if (((drv->states[idx].flags & CPUIDLE_FLAG_POLLING) ||
expected_interval < TICK_USEC) && !tick_nohz_tick_stopped()) {
predicted_us < TICK_USEC) && !tick_nohz_tick_stopped()) {
unsigned int delta_next_us = ktime_to_us(delta_next);
*stop_tick = false;
@ -450,10 +459,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
}
}
out:
data->last_state_idx = idx;
return data->last_state_idx;
return idx;
}
/**
@ -512,9 +518,19 @@ static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
* duration predictor do a better job next time.
*/
measured_us = 9 * MAX_INTERESTING / 10;
} else if ((drv->states[last_idx].flags & CPUIDLE_FLAG_POLLING) &&
dev->poll_time_limit) {
/*
* The CPU exited the "polling" state due to a time limit, so
* the idle duration prediction leading to the selection of that
* state was inaccurate. If a better prediction had been made,
* the CPU might have been woken up from idle by the next timer.
* Assume that to be the case.
*/
measured_us = data->next_timer_us;
} else {
/* measured value */
measured_us = cpuidle_get_last_residency(dev);
measured_us = dev->last_residency;
/* Deduct exit latency */
if (measured_us > 2 * target->exit_latency)

8
drivers/cpuidle/poll_state.c
View File

@ -9,7 +9,6 @@
#include <linux/sched/clock.h>
#include <linux/sched/idle.h>
#define POLL_IDLE_TIME_LIMIT (TICK_NSEC / 16)
#define POLL_IDLE_RELAX_COUNT 200
static int __cpuidle poll_idle(struct cpuidle_device *dev,
@ -17,8 +16,11 @@ static int __cpuidle poll_idle(struct cpuidle_device *dev,
{
u64 time_start = local_clock();
dev->poll_time_limit = false;
local_irq_enable();
if (!current_set_polling_and_test()) {
u64 limit = (u64)drv->states[1].target_residency * NSEC_PER_USEC;
unsigned int loop_count = 0;
while (!need_resched()) {
@ -27,8 +29,10 @@ static int __cpuidle poll_idle(struct cpuidle_device *dev,
continue;
loop_count = 0;
if (local_clock() - time_start > POLL_IDLE_TIME_LIMIT)
if (local_clock() - time_start > limit) {
dev->poll_time_limit = true;
break;
}
}
}
current_clr_polling();

75
drivers/idle/intel_idle.c
View File

@ -1066,46 +1066,43 @@ static const struct idle_cpu idle_cpu_dnv = {
.disable_promotion_to_c1e = true,
};
#define ICPU(model, cpu) \
{ X86_VENDOR_INTEL, 6, model, X86_FEATURE_ANY, (unsigned long)&cpu }
static const struct x86_cpu_id intel_idle_ids[] __initconst = {
ICPU(INTEL_FAM6_NEHALEM_EP, idle_cpu_nehalem),
ICPU(INTEL_FAM6_NEHALEM, idle_cpu_nehalem),
ICPU(INTEL_FAM6_NEHALEM_G, idle_cpu_nehalem),
ICPU(INTEL_FAM6_WESTMERE, idle_cpu_nehalem),
ICPU(INTEL_FAM6_WESTMERE_EP, idle_cpu_nehalem),
ICPU(INTEL_FAM6_NEHALEM_EX, idle_cpu_nehalem),
ICPU(INTEL_FAM6_ATOM_PINEVIEW, idle_cpu_atom),
ICPU(INTEL_FAM6_ATOM_LINCROFT, idle_cpu_lincroft),
ICPU(INTEL_FAM6_WESTMERE_EX, idle_cpu_nehalem),
ICPU(INTEL_FAM6_SANDYBRIDGE, idle_cpu_snb),
ICPU(INTEL_FAM6_SANDYBRIDGE_X, idle_cpu_snb),
ICPU(INTEL_FAM6_ATOM_CEDARVIEW, idle_cpu_atom),
ICPU(INTEL_FAM6_ATOM_SILVERMONT1, idle_cpu_byt),
ICPU(INTEL_FAM6_ATOM_MERRIFIELD, idle_cpu_tangier),
ICPU(INTEL_FAM6_ATOM_AIRMONT, idle_cpu_cht),
ICPU(INTEL_FAM6_IVYBRIDGE, idle_cpu_ivb),
ICPU(INTEL_FAM6_IVYBRIDGE_X, idle_cpu_ivt),
ICPU(INTEL_FAM6_HASWELL_CORE, idle_cpu_hsw),
ICPU(INTEL_FAM6_HASWELL_X, idle_cpu_hsw),
ICPU(INTEL_FAM6_HASWELL_ULT, idle_cpu_hsw),
ICPU(INTEL_FAM6_HASWELL_GT3E, idle_cpu_hsw),
ICPU(INTEL_FAM6_ATOM_SILVERMONT2, idle_cpu_avn),
ICPU(INTEL_FAM6_BROADWELL_CORE, idle_cpu_bdw),
ICPU(INTEL_FAM6_BROADWELL_GT3E, idle_cpu_bdw),
ICPU(INTEL_FAM6_BROADWELL_X, idle_cpu_bdw),
ICPU(INTEL_FAM6_BROADWELL_XEON_D, idle_cpu_bdw),
ICPU(INTEL_FAM6_SKYLAKE_MOBILE, idle_cpu_skl),
ICPU(INTEL_FAM6_SKYLAKE_DESKTOP, idle_cpu_skl),
ICPU(INTEL_FAM6_KABYLAKE_MOBILE, idle_cpu_skl),
ICPU(INTEL_FAM6_KABYLAKE_DESKTOP, idle_cpu_skl),
ICPU(INTEL_FAM6_SKYLAKE_X, idle_cpu_skx),
ICPU(INTEL_FAM6_XEON_PHI_KNL, idle_cpu_knl),
ICPU(INTEL_FAM6_XEON_PHI_KNM, idle_cpu_knl),
ICPU(INTEL_FAM6_ATOM_GOLDMONT, idle_cpu_bxt),
ICPU(INTEL_FAM6_ATOM_GEMINI_LAKE, idle_cpu_bxt),
ICPU(INTEL_FAM6_ATOM_DENVERTON, idle_cpu_dnv),
INTEL_CPU_FAM6(NEHALEM_EP, idle_cpu_nehalem),
INTEL_CPU_FAM6(NEHALEM, idle_cpu_nehalem),
INTEL_CPU_FAM6(NEHALEM_G, idle_cpu_nehalem),
INTEL_CPU_FAM6(WESTMERE, idle_cpu_nehalem),
INTEL_CPU_FAM6(WESTMERE_EP, idle_cpu_nehalem),
INTEL_CPU_FAM6(NEHALEM_EX, idle_cpu_nehalem),
INTEL_CPU_FAM6(ATOM_PINEVIEW, idle_cpu_atom),
INTEL_CPU_FAM6(ATOM_LINCROFT, idle_cpu_lincroft),
INTEL_CPU_FAM6(WESTMERE_EX, idle_cpu_nehalem),
INTEL_CPU_FAM6(SANDYBRIDGE, idle_cpu_snb),
INTEL_CPU_FAM6(SANDYBRIDGE_X, idle_cpu_snb),
INTEL_CPU_FAM6(ATOM_CEDARVIEW, idle_cpu_atom),
INTEL_CPU_FAM6(ATOM_SILVERMONT1, idle_cpu_byt),
INTEL_CPU_FAM6(ATOM_MERRIFIELD, idle_cpu_tangier),
INTEL_CPU_FAM6(ATOM_AIRMONT, idle_cpu_cht),
INTEL_CPU_FAM6(IVYBRIDGE, idle_cpu_ivb),
INTEL_CPU_FAM6(IVYBRIDGE_X, idle_cpu_ivt),
INTEL_CPU_FAM6(HASWELL_CORE, idle_cpu_hsw),
INTEL_CPU_FAM6(HASWELL_X, idle_cpu_hsw),
INTEL_CPU_FAM6(HASWELL_ULT, idle_cpu_hsw),
INTEL_CPU_FAM6(HASWELL_GT3E, idle_cpu_hsw),
INTEL_CPU_FAM6(ATOM_SILVERMONT2, idle_cpu_avn),
INTEL_CPU_FAM6(BROADWELL_CORE, idle_cpu_bdw),
INTEL_CPU_FAM6(BROADWELL_GT3E, idle_cpu_bdw),
INTEL_CPU_FAM6(BROADWELL_X, idle_cpu_bdw),
INTEL_CPU_FAM6(BROADWELL_XEON_D, idle_cpu_bdw),
INTEL_CPU_FAM6(SKYLAKE_MOBILE, idle_cpu_skl),
INTEL_CPU_FAM6(SKYLAKE_DESKTOP, idle_cpu_skl),
INTEL_CPU_FAM6(KABYLAKE_MOBILE, idle_cpu_skl),
INTEL_CPU_FAM6(KABYLAKE_DESKTOP, idle_cpu_skl),
INTEL_CPU_FAM6(SKYLAKE_X, idle_cpu_skx),
INTEL_CPU_FAM6(XEON_PHI_KNL, idle_cpu_knl),
INTEL_CPU_FAM6(XEON_PHI_KNM, idle_cpu_knl),
INTEL_CPU_FAM6(ATOM_GOLDMONT, idle_cpu_bxt),
INTEL_CPU_FAM6(ATOM_GEMINI_LAKE, idle_cpu_bxt),
INTEL_CPU_FAM6(ATOM_DENVERTON, idle_cpu_dnv),
{}
};

11
include/linux/cpuidle.h
View File

@ -81,6 +81,7 @@ struct cpuidle_device {
unsigned int registered:1;
unsigned int enabled:1;
unsigned int use_deepest_state:1;
unsigned int poll_time_limit:1;
unsigned int cpu;
int last_residency;
@ -99,16 +100,6 @@ struct cpuidle_device {
DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
DECLARE_PER_CPU(struct cpuidle_device, cpuidle_dev);
/**
* cpuidle_get_last_residency - retrieves the last state's residency time
* @dev: the target CPU
*/
static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
{
return dev->last_residency;
}
/****************************
* CPUIDLE DRIVER INTERFACE *
****************************/