cpuidle: Use nanoseconds as the unit of time
authorRafael J. Wysocki <rafael.j.wysocki@intel.com>
Thu, 7 Nov 2019 14:25:12 +0000 (15:25 +0100)
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>
Mon, 11 Nov 2019 20:56:07 +0000 (21:56 +0100)
Currently, the cpuidle subsystem uses microseconds as the unit of
time which (among other things) causes the idle loop to incur some
integer division overhead for no clear benefit.

In order to allow cpuidle to measure time in nanoseconds, add two
new fields, exit_latency_ns and target_residency_ns, to represent the
exit latency and target residency of an idle state in nanoseconds,
respectively, to struct cpuidle_state and initialize them with the
help of the corresponding values in microseconds provided by drivers.
Additionally, change cpuidle_governor_latency_req() to return the
idle state exit latency constraint in nanoseconds.

Also meeasure idle state residency (last_residency_ns in struct
cpuidle_device and time_ns in struct cpuidle_driver) in nanoseconds
and update the cpuidle core and governors accordingly.

However, the menu governor still computes typical intervals in
microseconds to avoid integer overflows.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Doug Smythies <dsmythies@telus.net>
Tested-by: Doug Smythies <dsmythies@telus.net>
drivers/cpuidle/cpuidle.c
drivers/cpuidle/driver.c
drivers/cpuidle/governor.c
drivers/cpuidle/governors/haltpoll.c
drivers/cpuidle/governors/ladder.c
drivers/cpuidle/governors/menu.c
drivers/cpuidle/governors/teo.c
drivers/cpuidle/poll_state.c
drivers/cpuidle/sysfs.c
include/linux/cpuidle.h
kernel/sched/idle.c

index 44ae39f2b47a2268d4a13f78edd689afed9e8b3c..bf9b030cd7e12f3b8e35424a91b8c7dbf0040e8e 100644 (file)
@@ -75,24 +75,24 @@ int cpuidle_play_dead(void)
 
 static int find_deepest_state(struct cpuidle_driver *drv,
                              struct cpuidle_device *dev,
-                             unsigned int max_latency,
+                             u64 max_latency_ns,
                              unsigned int forbidden_flags,
                              bool s2idle)
 {
-       unsigned int latency_req = 0;
+       u64 latency_req = 0;
        int i, ret = 0;
 
        for (i = 1; i < drv->state_count; i++) {
                struct cpuidle_state *s = &drv->states[i];
 
                if (dev->states_usage[i].disable ||
-                   s->exit_latency <= latency_req ||
-                   s->exit_latency > max_latency ||
+                   s->exit_latency_ns <= latency_req ||
+                   s->exit_latency_ns > max_latency_ns ||
                    (s->flags & forbidden_flags) ||
                    (s2idle && !s->enter_s2idle))
                        continue;
 
-               latency_req = s->exit_latency;
+               latency_req = s->exit_latency_ns;
                ret = i;
        }
        return ret;
@@ -124,7 +124,7 @@ void cpuidle_use_deepest_state(bool enable)
 int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
                               struct cpuidle_device *dev)
 {
-       return find_deepest_state(drv, dev, UINT_MAX, 0, false);
+       return find_deepest_state(drv, dev, U64_MAX, 0, false);
 }
 
 #ifdef CONFIG_SUSPEND
@@ -180,7 +180,7 @@ int cpuidle_enter_s2idle(struct cpuidle_driver *drv, struct cpuidle_device *dev)
         * that interrupts won't be enabled when it exits and allows the tick to
         * be frozen safely.
         */
-       index = find_deepest_state(drv, dev, UINT_MAX, 0, true);
+       index = find_deepest_state(drv, dev, U64_MAX, 0, true);
        if (index > 0)
                enter_s2idle_proper(drv, dev, index);
 
@@ -209,7 +209,7 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
         * CPU as a broadcast timer, this call may fail if it is not available.
         */
        if (broadcast && tick_broadcast_enter()) {
-               index = find_deepest_state(drv, dev, target_state->exit_latency,
+               index = find_deepest_state(drv, dev, target_state->exit_latency_ns,
                                           CPUIDLE_FLAG_TIMER_STOP, false);
                if (index < 0) {
                        default_idle_call();
@@ -247,7 +247,7 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
                local_irq_enable();
 
        if (entered_state >= 0) {
-               s64 diff, delay = drv->states[entered_state].exit_latency;
+               s64 diff, delay = drv->states[entered_state].exit_latency_ns;
                int i;
 
                /*
@@ -255,15 +255,13 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
                 * 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;
+               diff = ktime_sub(time_end, time_start);
 
-               dev->last_residency = (int)diff;
-               dev->states_usage[entered_state].time += dev->last_residency;
+               dev->last_residency_ns = diff;
+               dev->states_usage[entered_state].time_ns += diff;
                dev->states_usage[entered_state].usage++;
 
-               if (diff < drv->states[entered_state].target_residency) {
+               if (diff < drv->states[entered_state].target_residency_ns) {
                        for (i = entered_state - 1; i >= 0; i--) {
                                if (dev->states_usage[i].disable)
                                        continue;
@@ -281,14 +279,14 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
                                 * Update if a deeper state would have been a
                                 * better match for the observed idle duration.
                                 */
-                               if (diff - delay >= drv->states[i].target_residency)
+                               if (diff - delay >= drv->states[i].target_residency_ns)
                                        dev->states_usage[entered_state].below++;
 
                                break;
                        }
                }
        } else {
-               dev->last_residency = 0;
+               dev->last_residency_ns = 0;
        }
 
        return entered_state;
@@ -381,7 +379,7 @@ u64 cpuidle_poll_time(struct cpuidle_driver *drv,
                if (dev->states_usage[i].disable)
                        continue;
 
-               limit_ns = (u64)drv->states[i].target_residency * NSEC_PER_USEC;
+               limit_ns = (u64)drv->states[i].target_residency_ns;
        }
 
        dev->poll_limit_ns = limit_ns;
@@ -552,7 +550,7 @@ static void __cpuidle_unregister_device(struct cpuidle_device *dev)
 static void __cpuidle_device_init(struct cpuidle_device *dev)
 {
        memset(dev->states_usage, 0, sizeof(dev->states_usage));
-       dev->last_residency = 0;
+       dev->last_residency_ns = 0;
        dev->next_hrtimer = 0;
 }
 
index 9db154224999c9e6d7a2704b0b685bdb7658b134..fcaf8b2bab967b0ff1cd7680c17639324101adca 100644 (file)
@@ -165,16 +165,27 @@ static void __cpuidle_driver_init(struct cpuidle_driver *drv)
        if (!drv->cpumask)
                drv->cpumask = (struct cpumask *)cpu_possible_mask;
 
-       /*
-        * Look for the timer stop flag in the different states, so that we know
-        * if the broadcast timer has to be set up.  The loop is in the reverse
-        * order, because usually one of the deeper states have this flag set.
-        */
-       for (i = drv->state_count - 1; i >= 0 ; i--) {
-               if (drv->states[i].flags & CPUIDLE_FLAG_TIMER_STOP) {
+       for (i = 0; i < drv->state_count; i++) {
+               struct cpuidle_state *s = &drv->states[i];
+
+               /*
+                * Look for the timer stop flag in the different states and if
+                * it is found, indicate that the broadcast timer has to be set
+                * up.
+                */
+               if (s->flags & CPUIDLE_FLAG_TIMER_STOP)
                        drv->bctimer = 1;
-                       break;
-               }
+
+               /*
+                * The core will use the target residency and exit latency
+                * values in nanoseconds, but allow drivers to provide them in
+                * microseconds too.
+                */
+               if (s->target_residency > 0)
+                       s->target_residency_ns = s->target_residency * NSEC_PER_USEC;
+
+               if (s->exit_latency > 0)
+                       s->exit_latency_ns = s->exit_latency * NSEC_PER_USEC;
        }
 }
 
index e9801f26c73270c6665a117a60b1e45d32186217..e48271e117a32852eac4674a1f332f97db682834 100644 (file)
@@ -107,11 +107,14 @@ int cpuidle_register_governor(struct cpuidle_governor *gov)
  * cpuidle_governor_latency_req - Compute a latency constraint for CPU
  * @cpu: Target CPU
  */
-int cpuidle_governor_latency_req(unsigned int cpu)
+s64 cpuidle_governor_latency_req(unsigned int cpu)
 {
        int global_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY);
        struct device *device = get_cpu_device(cpu);
        int device_req = dev_pm_qos_raw_resume_latency(device);
 
-       return device_req < global_req ? device_req : global_req;
+       if (device_req > global_req)
+               device_req = global_req;
+
+       return (s64)device_req * NSEC_PER_USEC;
 }
index 7a703d2e006403cc73cd443a326c5adcb3bf58c9..cb2a96eafc02750acc5e7e66fa53cea18a50523a 100644 (file)
@@ -49,7 +49,7 @@ static int haltpoll_select(struct cpuidle_driver *drv,
                           struct cpuidle_device *dev,
                           bool *stop_tick)
 {
-       int latency_req = cpuidle_governor_latency_req(dev->cpu);
+       s64 latency_req = cpuidle_governor_latency_req(dev->cpu);
 
        if (!drv->state_count || latency_req == 0) {
                *stop_tick = false;
@@ -75,10 +75,9 @@ static int haltpoll_select(struct cpuidle_driver *drv,
        return 0;
 }
 
-static void adjust_poll_limit(struct cpuidle_device *dev, unsigned int block_us)
+static void adjust_poll_limit(struct cpuidle_device *dev, u64 block_ns)
 {
        unsigned int val;
-       u64 block_ns = block_us*NSEC_PER_USEC;
 
        /* Grow cpu_halt_poll_us if
         * cpu_halt_poll_us < block_ns < guest_halt_poll_us
@@ -115,7 +114,7 @@ static void haltpoll_reflect(struct cpuidle_device *dev, int index)
        dev->last_state_idx = index;
 
        if (index != 0)
-               adjust_poll_limit(dev, dev->last_residency);
+               adjust_poll_limit(dev, dev->last_residency_ns);
 }
 
 /**
index b0126b8c32fe94a8fadabb80ea2feeae6e2bd113..8e9058c4ea63e1217ad33d2f61dd8e768187af0a 100644 (file)
@@ -27,8 +27,8 @@ struct ladder_device_state {
        struct {
                u32 promotion_count;
                u32 demotion_count;
-               u32 promotion_time;
-               u32 demotion_time;
+               u64 promotion_time_ns;
+               u64 demotion_time_ns;
        } threshold;
        struct {
                int promotion_count;
@@ -68,9 +68,10 @@ static int ladder_select_state(struct cpuidle_driver *drv,
 {
        struct ladder_device *ldev = this_cpu_ptr(&ladder_devices);
        struct ladder_device_state *last_state;
-       int last_residency, last_idx = dev->last_state_idx;
+       int last_idx = dev->last_state_idx;
        int first_idx = drv->states[0].flags & CPUIDLE_FLAG_POLLING ? 1 : 0;
-       int latency_req = cpuidle_governor_latency_req(dev->cpu);
+       s64 latency_req = cpuidle_governor_latency_req(dev->cpu);
+       s64 last_residency;
 
        /* Special case when user has set very strict latency requirement */
        if (unlikely(latency_req == 0)) {
@@ -80,13 +81,13 @@ static int ladder_select_state(struct cpuidle_driver *drv,
 
        last_state = &ldev->states[last_idx];
 
-       last_residency = dev->last_residency - drv->states[last_idx].exit_latency;
+       last_residency = dev->last_residency_ns - drv->states[last_idx].exit_latency_ns;
 
        /* consider promotion */
        if (last_idx < drv->state_count - 1 &&
            !dev->states_usage[last_idx + 1].disable &&
-           last_residency > last_state->threshold.promotion_time &&
-           drv->states[last_idx + 1].exit_latency <= latency_req) {
+           last_residency > last_state->threshold.promotion_time_ns &&
+           drv->states[last_idx + 1].exit_latency_ns <= latency_req) {
                last_state->stats.promotion_count++;
                last_state->stats.demotion_count = 0;
                if (last_state->stats.promotion_count >= last_state->threshold.promotion_count) {
@@ -98,11 +99,11 @@ static int ladder_select_state(struct cpuidle_driver *drv,
        /* consider demotion */
        if (last_idx > first_idx &&
            (dev->states_usage[last_idx].disable ||
-           drv->states[last_idx].exit_latency > latency_req)) {
+           drv->states[last_idx].exit_latency_ns > latency_req)) {
                int i;
 
                for (i = last_idx - 1; i > first_idx; i--) {
-                       if (drv->states[i].exit_latency <= latency_req)
+                       if (drv->states[i].exit_latency_ns <= latency_req)
                                break;
                }
                ladder_do_selection(dev, ldev, last_idx, i);
@@ -110,7 +111,7 @@ static int ladder_select_state(struct cpuidle_driver *drv,
        }
 
        if (last_idx > first_idx &&
-           last_residency < last_state->threshold.demotion_time) {
+           last_residency < last_state->threshold.demotion_time_ns) {
                last_state->stats.demotion_count++;
                last_state->stats.promotion_count = 0;
                if (last_state->stats.demotion_count >= last_state->threshold.demotion_count) {
@@ -150,9 +151,9 @@ static int ladder_enable_device(struct cpuidle_driver *drv,
                lstate->threshold.demotion_count = DEMOTION_COUNT;
 
                if (i < drv->state_count - 1)
-                       lstate->threshold.promotion_time = state->exit_latency;
+                       lstate->threshold.promotion_time_ns = state->exit_latency_ns;
                if (i > first_idx)
-                       lstate->threshold.demotion_time = state->exit_latency;
+                       lstate->threshold.demotion_time_ns = state->exit_latency_ns;
        }
 
        return 0;
index 38b2b72102a8dc77bb46259b4f01693d6e4d8a96..b0a7ad566081a2f3d9b51f3a3d52ae9263064b33 100644 (file)
 #include <linux/sched/stat.h>
 #include <linux/math64.h>
 
-/*
- * Please note when changing the tuning values:
- * If (MAX_INTERESTING-1) * RESOLUTION > UINT_MAX, the result of
- * a scaling operation multiplication may overflow on 32 bit platforms.
- * In that case, #define RESOLUTION as ULL to get 64 bit result:
- * #define RESOLUTION 1024ULL
- *
- * The default values do not overflow.
- */
 #define BUCKETS 12
 #define INTERVAL_SHIFT 3
 #define INTERVALS (1UL << INTERVAL_SHIFT)
 #define RESOLUTION 1024
 #define DECAY 8
-#define MAX_INTERESTING 50000
-
+#define MAX_INTERESTING (50000 * NSEC_PER_USEC)
 
 /*
  * Concepts and ideas behind the menu governor
@@ -120,14 +110,14 @@ struct menu_device {
        int             needs_update;
        int             tick_wakeup;
 
-       unsigned int    next_timer_us;
+       u64             next_timer_ns;
        unsigned int    bucket;
        unsigned int    correction_factor[BUCKETS];
        unsigned int    intervals[INTERVALS];
        int             interval_ptr;
 };
 
-static inline int which_bucket(unsigned int duration, unsigned long nr_iowaiters)
+static inline int which_bucket(u64 duration_ns, unsigned long nr_iowaiters)
 {
        int bucket = 0;
 
@@ -140,15 +130,15 @@ static inline int which_bucket(unsigned int duration, unsigned long nr_iowaiters
        if (nr_iowaiters)
                bucket = BUCKETS/2;
 
-       if (duration < 10)
+       if (duration_ns < 10ULL * NSEC_PER_USEC)
                return bucket;
-       if (duration < 100)
+       if (duration_ns < 100ULL * NSEC_PER_USEC)
                return bucket + 1;
-       if (duration < 1000)
+       if (duration_ns < 1000ULL * NSEC_PER_USEC)
                return bucket + 2;
-       if (duration < 10000)
+       if (duration_ns < 10000ULL * NSEC_PER_USEC)
                return bucket + 3;
-       if (duration < 100000)
+       if (duration_ns < 100000ULL * NSEC_PER_USEC)
                return bucket + 4;
        return bucket + 5;
 }
@@ -276,13 +266,13 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
                       bool *stop_tick)
 {
        struct menu_device *data = this_cpu_ptr(&menu_devices);
-       int latency_req = cpuidle_governor_latency_req(dev->cpu);
-       int i;
-       int idx;
-       unsigned int interactivity_req;
+       s64 latency_req = cpuidle_governor_latency_req(dev->cpu);
        unsigned int predicted_us;
+       u64 predicted_ns;
+       u64 interactivity_req;
        unsigned long nr_iowaiters;
        ktime_t delta_next;
+       int i, idx;
 
        if (data->needs_update) {
                menu_update(drv, dev);
@@ -290,14 +280,14 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
        }
 
        /* determine the expected residency time, round up */
-       data->next_timer_us = ktime_to_us(tick_nohz_get_sleep_length(&delta_next));
+       data->next_timer_ns = tick_nohz_get_sleep_length(&delta_next);
 
        nr_iowaiters = nr_iowait_cpu(dev->cpu);
-       data->bucket = which_bucket(data->next_timer_us, nr_iowaiters);
+       data->bucket = which_bucket(data->next_timer_ns, 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) &&
+           ((data->next_timer_ns < drv->states[1].target_residency_ns ||
+             latency_req < drv->states[1].exit_latency_ns) &&
             !dev->states_usage[0].disable)) {
                /*
                 * In this case state[0] will be used no matter what, so return
@@ -308,18 +298,15 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
                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.
-        */
-       predicted_us = DIV_ROUND_CLOSEST_ULL((uint64_t)data->next_timer_us *
-                                        data->correction_factor[data->bucket],
-                                        RESOLUTION * DECAY);
-       /*
-        * Use the lowest expected idle interval to pick the idle state.
-        */
-       predicted_us = min(predicted_us, get_typical_interval(data, predicted_us));
+       /* Round up the result for half microseconds. */
+       predicted_us = div_u64(data->next_timer_ns *
+                              data->correction_factor[data->bucket] +
+                              (RESOLUTION * DECAY * NSEC_PER_USEC) / 2,
+                              RESOLUTION * DECAY * NSEC_PER_USEC);
+       /* Use the lowest expected idle interval to pick the idle state. */
+       predicted_ns = (u64)min(predicted_us,
+                               get_typical_interval(data, predicted_us)) *
+                               NSEC_PER_USEC;
 
        if (tick_nohz_tick_stopped()) {
                /*
@@ -330,14 +317,15 @@ 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 (predicted_us < TICK_USEC)
-                       predicted_us = ktime_to_us(delta_next);
+               if (predicted_ns < TICK_NSEC)
+                       predicted_ns = delta_next;
        } else {
                /*
                 * Use the performance multiplier and the user-configurable
                 * latency_req to determine the maximum exit latency.
                 */
-               interactivity_req = predicted_us / performance_multiplier(nr_iowaiters);
+               interactivity_req = div64_u64(predicted_ns,
+                                             performance_multiplier(nr_iowaiters));
                if (latency_req > interactivity_req)
                        latency_req = interactivity_req;
        }
@@ -356,19 +344,19 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
                if (idx == -1)
                        idx = i; /* first enabled state */
 
-               if (s->target_residency > predicted_us) {
+               if (s->target_residency_ns > predicted_ns) {
                        /*
                         * 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;
+                           s->exit_latency_ns <= latency_req &&
+                           s->target_residency_ns <= data->next_timer_ns) {
+                               predicted_ns = s->target_residency_ns;
                                idx = i;
                                break;
                        }
-                       if (predicted_us < TICK_USEC)
+                       if (predicted_ns < TICK_NSEC)
                                break;
 
                        if (!tick_nohz_tick_stopped()) {
@@ -378,7 +366,7 @@ 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.
                                 */
-                               predicted_us = drv->states[idx].target_residency;
+                               predicted_ns = drv->states[idx].target_residency_ns;
                                break;
                        }
 
@@ -388,13 +376,13 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
                         * closest timer event, select this one to avoid getting
                         * stuck in the shallow one for too long.
                         */
-                       if (drv->states[idx].target_residency < TICK_USEC &&
-                           s->target_residency <= ktime_to_us(delta_next))
+                       if (drv->states[idx].target_residency_ns < TICK_NSEC &&
+                           s->target_residency_ns <= delta_next)
                                idx = i;
 
                        return idx;
                }
-               if (s->exit_latency > latency_req)
+               if (s->exit_latency_ns > latency_req)
                        break;
 
                idx = i;
@@ -408,12 +396,10 @@ 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) ||
-            predicted_us < TICK_USEC) && !tick_nohz_tick_stopped()) {
-               unsigned int delta_next_us = ktime_to_us(delta_next);
-
+            predicted_ns < TICK_NSEC) && !tick_nohz_tick_stopped()) {
                *stop_tick = false;
 
-               if (idx > 0 && drv->states[idx].target_residency > delta_next_us) {
+               if (idx > 0 && drv->states[idx].target_residency_ns > delta_next) {
                        /*
                         * The tick is not going to be stopped and the target
                         * residency of the state to be returned is not within
@@ -425,7 +411,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
                                        continue;
 
                                idx = i;
-                               if (drv->states[i].target_residency <= delta_next_us)
+                               if (drv->states[i].target_residency_ns <= delta_next)
                                        break;
                        }
                }
@@ -461,7 +447,7 @@ static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
        struct menu_device *data = this_cpu_ptr(&menu_devices);
        int last_idx = dev->last_state_idx;
        struct cpuidle_state *target = &drv->states[last_idx];
-       unsigned int measured_us;
+       u64 measured_ns;
        unsigned int new_factor;
 
        /*
@@ -479,7 +465,7 @@ static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
         * assume the state was never reached and the exit latency is 0.
         */
 
-       if (data->tick_wakeup && data->next_timer_us > TICK_USEC) {
+       if (data->tick_wakeup && data->next_timer_ns > TICK_NSEC) {
                /*
                 * The nohz code said that there wouldn't be any events within
                 * the tick boundary (if the tick was stopped), but the idle
@@ -489,7 +475,7 @@ static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
                 * have been idle long (but not forever) to help the idle
                 * duration predictor do a better job next time.
                 */
-               measured_us = 9 * MAX_INTERESTING / 10;
+               measured_ns = 9 * MAX_INTERESTING / 10;
        } else if ((drv->states[last_idx].flags & CPUIDLE_FLAG_POLLING) &&
                   dev->poll_time_limit) {
                /*
@@ -499,28 +485,29 @@ static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
                 * 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;
+               measured_ns = data->next_timer_ns;
        } else {
                /* measured value */
-               measured_us = dev->last_residency;
+               measured_ns = dev->last_residency_ns;
 
                /* Deduct exit latency */
-               if (measured_us > 2 * target->exit_latency)
-                       measured_us -= target->exit_latency;
+               if (measured_ns > 2 * target->exit_latency_ns)
+                       measured_ns -= target->exit_latency_ns;
                else
-                       measured_us /= 2;
+                       measured_ns /= 2;
        }
 
        /* Make sure our coefficients do not exceed unity */
-       if (measured_us > data->next_timer_us)
-               measured_us = data->next_timer_us;
+       if (measured_ns > data->next_timer_ns)
+               measured_ns = data->next_timer_ns;
 
        /* Update our correction ratio */
        new_factor = data->correction_factor[data->bucket];
        new_factor -= new_factor / DECAY;
 
-       if (data->next_timer_us > 0 && measured_us < MAX_INTERESTING)
-               new_factor += RESOLUTION * measured_us / data->next_timer_us;
+       if (data->next_timer_ns > 0 && measured_ns < MAX_INTERESTING)
+               new_factor += div64_u64(RESOLUTION * measured_ns,
+                                       data->next_timer_ns);
        else
                /*
                 * we were idle so long that we count it as a perfect
@@ -540,7 +527,7 @@ static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
        data->correction_factor[data->bucket] = new_factor;
 
        /* update the repeating-pattern data */
-       data->intervals[data->interval_ptr++] = measured_us;
+       data->intervals[data->interval_ptr++] = ktime_to_us(measured_ns);
        if (data->interval_ptr >= INTERVALS)
                data->interval_ptr = 0;
 }
index 702d560eb34769ccb9895fa1f8ccc94e0766edda..ecbcfaefb0cd9198149ef4e2d4ad931d1c376300 100644 (file)
@@ -104,7 +104,7 @@ struct teo_cpu {
        u64 sleep_length_ns;
        struct teo_idle_state states[CPUIDLE_STATE_MAX];
        int interval_idx;
-       unsigned int intervals[INTERVALS];
+       u64 intervals[INTERVALS];
 };
 
 static DEFINE_PER_CPU(struct teo_cpu, teo_cpus);
@@ -117,9 +117,8 @@ static DEFINE_PER_CPU(struct teo_cpu, teo_cpus);
 static void teo_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
 {
        struct teo_cpu *cpu_data = per_cpu_ptr(&teo_cpus, dev->cpu);
-       unsigned int sleep_length_us = ktime_to_us(cpu_data->sleep_length_ns);
        int i, idx_hit = -1, idx_timer = -1;
-       unsigned int measured_us;
+       u64 measured_ns;
 
        if (cpu_data->time_span_ns >= cpu_data->sleep_length_ns) {
                /*
@@ -127,23 +126,21 @@ static void teo_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
                 * enough to the closest timer event expected at the idle state
                 * selection time to be discarded.
                 */
-               measured_us = UINT_MAX;
+               measured_ns = U64_MAX;
        } else {
-               unsigned int lat;
+               u64 lat_ns = drv->states[dev->last_state_idx].exit_latency_ns;
 
-               lat = drv->states[dev->last_state_idx].exit_latency;
-
-               measured_us = ktime_to_us(cpu_data->time_span_ns);
+               measured_ns = cpu_data->time_span_ns;
                /*
                 * The delay between the wakeup and the first instruction
                 * executed by the CPU is not likely to be worst-case every
                 * time, so take 1/2 of the exit latency as a very rough
                 * approximation of the average of it.
                 */
-               if (measured_us >= lat)
-                       measured_us -= lat / 2;
+               if (measured_ns >= lat_ns)
+                       measured_ns -= lat_ns / 2;
                else
-                       measured_us /= 2;
+                       measured_ns /= 2;
        }
 
        /*
@@ -155,9 +152,9 @@ static void teo_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
 
                cpu_data->states[i].early_hits -= early_hits >> DECAY_SHIFT;
 
-               if (drv->states[i].target_residency <= sleep_length_us) {
+               if (drv->states[i].target_residency_ns <= cpu_data->sleep_length_ns) {
                        idx_timer = i;
-                       if (drv->states[i].target_residency <= measured_us)
+                       if (drv->states[i].target_residency_ns <= measured_ns)
                                idx_hit = i;
                }
        }
@@ -193,7 +190,7 @@ static void teo_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
         * Save idle duration values corresponding to non-timer wakeups for
         * pattern detection.
         */
-       cpu_data->intervals[cpu_data->interval_idx++] = measured_us;
+       cpu_data->intervals[cpu_data->interval_idx++] = measured_ns;
        if (cpu_data->interval_idx > INTERVALS)
                cpu_data->interval_idx = 0;
 }
@@ -203,11 +200,11 @@ static void teo_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
  * @drv: cpuidle driver containing state data.
  * @dev: Target CPU.
  * @state_idx: Index of the capping idle state.
- * @duration_us: Idle duration value to match.
+ * @duration_ns: Idle duration value to match.
  */
 static int teo_find_shallower_state(struct cpuidle_driver *drv,
                                    struct cpuidle_device *dev, int state_idx,
-                                   unsigned int duration_us)
+                                   u64 duration_ns)
 {
        int i;
 
@@ -216,7 +213,7 @@ static int teo_find_shallower_state(struct cpuidle_driver *drv,
                        continue;
 
                state_idx = i;
-               if (drv->states[i].target_residency <= duration_us)
+               if (drv->states[i].target_residency_ns <= duration_ns)
                        break;
        }
        return state_idx;
@@ -232,8 +229,9 @@ static int teo_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
                      bool *stop_tick)
 {
        struct teo_cpu *cpu_data = per_cpu_ptr(&teo_cpus, dev->cpu);
-       int latency_req = cpuidle_governor_latency_req(dev->cpu);
-       unsigned int duration_us, hits, misses, early_hits;
+       s64 latency_req = cpuidle_governor_latency_req(dev->cpu);
+       u64 duration_ns;
+       unsigned int hits, misses, early_hits;
        int max_early_idx, constraint_idx, idx, i;
        ktime_t delta_tick;
 
@@ -244,8 +242,8 @@ static int teo_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
 
        cpu_data->time_span_ns = local_clock();
 
-       cpu_data->sleep_length_ns = tick_nohz_get_sleep_length(&delta_tick);
-       duration_us = ktime_to_us(cpu_data->sleep_length_ns);
+       duration_ns = tick_nohz_get_sleep_length(&delta_tick);
+       cpu_data->sleep_length_ns = duration_ns;
 
        hits = 0;
        misses = 0;
@@ -262,7 +260,7 @@ static int teo_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
                         * Ignore disabled states with target residencies beyond
                         * the anticipated idle duration.
                         */
-                       if (s->target_residency > duration_us)
+                       if (s->target_residency_ns > duration_ns)
                                continue;
 
                        /*
@@ -301,7 +299,7 @@ static int teo_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
                         * shallow for that role.
                         */
                        if (!(tick_nohz_tick_stopped() &&
-                             drv->states[idx].target_residency < TICK_USEC)) {
+                             drv->states[idx].target_residency_ns < TICK_NSEC)) {
                                early_hits = cpu_data->states[i].early_hits;
                                max_early_idx = idx;
                        }
@@ -315,10 +313,10 @@ static int teo_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
                        misses = cpu_data->states[i].misses;
                }
 
-               if (s->target_residency > duration_us)
+               if (s->target_residency_ns > duration_ns)
                        break;
 
-               if (s->exit_latency > latency_req && constraint_idx > i)
+               if (s->exit_latency_ns > latency_req && constraint_idx > i)
                        constraint_idx = i;
 
                idx = i;
@@ -327,7 +325,7 @@ static int teo_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
 
                if (early_hits < cpu_data->states[i].early_hits &&
                    !(tick_nohz_tick_stopped() &&
-                     drv->states[i].target_residency < TICK_USEC)) {
+                     drv->states[i].target_residency_ns < TICK_NSEC)) {
                        early_hits = cpu_data->states[i].early_hits;
                        max_early_idx = i;
                }
@@ -343,7 +341,7 @@ static int teo_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
         */
        if (hits <= misses && max_early_idx >= 0) {
                idx = max_early_idx;
-               duration_us = drv->states[idx].target_residency;
+               duration_ns = drv->states[idx].target_residency_ns;
        }
 
        /*
@@ -364,9 +362,9 @@ static int teo_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
                 * the current expected idle duration value.
                 */
                for (i = 0; i < INTERVALS; i++) {
-                       unsigned int val = cpu_data->intervals[i];
+                       u64 val = cpu_data->intervals[i];
 
-                       if (val >= duration_us)
+                       if (val >= duration_ns)
                                continue;
 
                        count++;
@@ -378,17 +376,17 @@ static int teo_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
                 * values are in the interesting range.
                 */
                if (count > INTERVALS / 2) {
-                       unsigned int avg_us = div64_u64(sum, count);
+                       u64 avg_ns = div64_u64(sum, count);
 
                        /*
                         * Avoid spending too much time in an idle state that
                         * would be too shallow.
                         */
-                       if (!(tick_nohz_tick_stopped() && avg_us < TICK_USEC)) {
-                               duration_us = avg_us;
-                               if (drv->states[idx].target_residency > avg_us)
+                       if (!(tick_nohz_tick_stopped() && avg_ns < TICK_NSEC)) {
+                               duration_ns = avg_ns;
+                               if (drv->states[idx].target_residency_ns > avg_ns)
                                        idx = teo_find_shallower_state(drv, dev,
-                                                                      idx, avg_us);
+                                                                      idx, avg_ns);
                        }
                }
        }
@@ -398,9 +396,7 @@ static int teo_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) ||
-           duration_us < TICK_USEC) && !tick_nohz_tick_stopped()) {
-               unsigned int delta_tick_us = ktime_to_us(delta_tick);
-
+           duration_ns < TICK_NSEC) && !tick_nohz_tick_stopped()) {
                *stop_tick = false;
 
                /*
@@ -409,8 +405,8 @@ static int teo_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
                 * till the closest timer including the tick, try to correct
                 * that.
                 */
-               if (idx > 0 && drv->states[idx].target_residency > delta_tick_us)
-                       idx = teo_find_shallower_state(drv, dev, idx, delta_tick_us);
+               if (idx > 0 && drv->states[idx].target_residency_ns > delta_tick)
+                       idx = teo_find_shallower_state(drv, dev, idx, delta_tick);
        }
 
        return idx;
@@ -454,7 +450,7 @@ static int teo_enable_device(struct cpuidle_driver *drv,
        memset(cpu_data, 0, sizeof(*cpu_data));
 
        for (i = 0; i < INTERVALS; i++)
-               cpu_data->intervals[i] = UINT_MAX;
+               cpu_data->intervals[i] = U64_MAX;
 
        return 0;
 }
index c8fa5f41dfc4cfdc5c0a33d091f748f747ad1b31..9f1ace9c53da56b627319bba97f9e2c93004a9e5 100644 (file)
@@ -49,6 +49,8 @@ void cpuidle_poll_state_init(struct cpuidle_driver *drv)
        snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE");
        state->exit_latency = 0;
        state->target_residency = 0;
+       state->exit_latency_ns = 0;
+       state->target_residency_ns = 0;
        state->power_usage = -1;
        state->enter = poll_idle;
        state->disabled = false;
index 9f3755ac8f8743bfb77c0c1f7fc9605af2b572c0..38ef770be90db82f1574fb6f85b2e951748413ae 100644 (file)
@@ -273,16 +273,30 @@ static ssize_t show_state_##_name(struct cpuidle_state *state, \
        return sprintf(buf, "%s\n", state->_name);\
 }
 
-define_show_state_function(exit_latency)
-define_show_state_function(target_residency)
+#define define_show_state_time_function(_name) \
+static ssize_t show_state_##_name(struct cpuidle_state *state, \
+                                 struct cpuidle_state_usage *state_usage, \
+                                 char *buf) \
+{ \
+       return sprintf(buf, "%llu\n", ktime_to_us(state->_name##_ns)); \
+}
+
+define_show_state_time_function(exit_latency)
+define_show_state_time_function(target_residency)
 define_show_state_function(power_usage)
 define_show_state_ull_function(usage)
-define_show_state_ull_function(time)
 define_show_state_str_function(name)
 define_show_state_str_function(desc)
 define_show_state_ull_function(above)
 define_show_state_ull_function(below)
 
+static ssize_t show_state_time(struct cpuidle_state *state,
+                              struct cpuidle_state_usage *state_usage,
+                              char *buf)
+{
+       return sprintf(buf, "%llu\n", ktime_to_us(state_usage->time_ns));
+}
+
 static ssize_t show_state_disable(struct cpuidle_state *state,
                                  struct cpuidle_state_usage *state_usage,
                                  char *buf)
index d23a3b1ddcf6243c284b3f3129a36757d8fadc3a..22602747f468035d19f383f3a1790d0d1bf28e1f 100644 (file)
@@ -35,7 +35,7 @@ struct cpuidle_driver;
 struct cpuidle_state_usage {
        unsigned long long      disable;
        unsigned long long      usage;
-       unsigned long long      time; /* in US */
+       u64                     time_ns;
        unsigned long long      above; /* Number of times it's been too deep */
        unsigned long long      below; /* Number of times it's been too shallow */
 #ifdef CONFIG_SUSPEND
@@ -48,6 +48,8 @@ struct cpuidle_state {
        char            name[CPUIDLE_NAME_LEN];
        char            desc[CPUIDLE_DESC_LEN];
 
+       u64             exit_latency_ns;
+       u64             target_residency_ns;
        unsigned int    flags;
        unsigned int    exit_latency; /* in US */
        int             power_usage; /* in mW */
@@ -89,7 +91,7 @@ struct cpuidle_device {
        ktime_t                 next_hrtimer;
 
        int                     last_state_idx;
-       int                     last_residency;
+       u64                     last_residency_ns;
        u64                     poll_limit_ns;
        struct cpuidle_state_usage      states_usage[CPUIDLE_STATE_MAX];
        struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
@@ -263,7 +265,7 @@ struct cpuidle_governor {
 
 #ifdef CONFIG_CPU_IDLE
 extern int cpuidle_register_governor(struct cpuidle_governor *gov);
-extern int cpuidle_governor_latency_req(unsigned int cpu);
+extern s64 cpuidle_governor_latency_req(unsigned int cpu);
 #else
 static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
 {return 0;}
index 8dad5aa600eacbff82480ef84eae684308e6da54..1aa260702b3861af5de658514c2d5f2fe4a5e522 100644 (file)
@@ -104,7 +104,7 @@ static int call_cpuidle(struct cpuidle_driver *drv, struct cpuidle_device *dev,
         * update no idle residency and return.
         */
        if (current_clr_polling_and_test()) {
-               dev->last_residency = 0;
+               dev->last_residency_ns = 0;
                local_irq_enable();
                return -EBUSY;
        }