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authorLinus Torvalds <torvalds@linux-foundation.org>2019-03-06 12:59:46 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-03-06 12:59:46 -0800
commitef8006846a3a97d9d8bf49e63dba948d0d2dbbf0 (patch)
tree5929135c14913ba7aebe538567d0550b80a61d73 /drivers/cpuidle
parentMerge branch 'akpm' (patches from Andrew) (diff)
parentMerge branch 'pm-opp' (diff)
downloadlinux-dev-ef8006846a3a97d9d8bf49e63dba948d0d2dbbf0.tar.xz
linux-dev-ef8006846a3a97d9d8bf49e63dba948d0d2dbbf0.zip
Merge tag 'pm-5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management updates from Rafael Wysocki: "These are PM-runtime framework changes to use ktime instead of jiffies for accounting, new PM core flag to mark devices that don't need any form of power management, cpuidle updates including driver API documentation and a new governor, cpufreq updates including a new driver for Armada 8K, thermal cleanups and more, some energy-aware scheduling (EAS) enabling changes, new chips support in the intel_idle and RAPL drivers and assorted cleanups in some other places. Specifics: - Update the PM-runtime framework to use ktime instead of jiffies for accounting (Thara Gopinath, Vincent Guittot) - Optimize the autosuspend code in the PM-runtime framework somewhat (Ladislav Michl) - Add a PM core flag to mark devices that don't need any form of power management (Sudeep Holla) - Introduce driver API documentation for cpuidle and add a new cpuidle governor for tickless systems (Rafael Wysocki) - Add Jacobsville support to the intel_idle driver (Zhang Rui) - Clean up a cpuidle core header file and the cpuidle-dt and ACPI processor-idle drivers (Yangtao Li, Joseph Lo, Yazen Ghannam) - Add new cpufreq driver for Armada 8K (Gregory Clement) - Fix and clean up cpufreq core (Rafael Wysocki, Viresh Kumar, Amit Kucheria) - Add support for light-weight tear-down and bring-up of CPUs to the cpufreq core and use it in the cpufreq-dt driver (Viresh Kumar) - Fix cpu_cooling Kconfig dependencies, add support for CPU cooling auto-registration to the cpufreq core and use it in multiple cpufreq drivers (Amit Kucheria) - Fix some minor issues and do some cleanups in the davinci, e_powersaver, ap806, s5pv210, qcom and kryo cpufreq drivers (Bartosz Golaszewski, Gustavo Silva, Julia Lawall, Paweł Chmiel, Taniya Das, Viresh Kumar) - Add a Hisilicon CPPC quirk to the cppc_cpufreq driver (Xiongfeng Wang) - Clean up the intel_pstate and acpi-cpufreq drivers (Erwan Velu, Rafael Wysocki) - Clean up multiple cpufreq drivers (Yangtao Li) - Update cpufreq-related MAINTAINERS entries (Baruch Siach, Lukas Bulwahn) - Add support for exposing the Energy Model via debugfs and make multiple cpufreq drivers register an Energy Model to support energy-aware scheduling (Quentin Perret, Dietmar Eggemann, Matthias Kaehlcke) - Add Ice Lake mobile and Jacobsville support to the Intel RAPL power-capping driver (Gayatri Kammela, Zhang Rui) - Add a power estimation helper to the operating performance points (OPP) framework and clean up a core function in it (Quentin Perret, Viresh Kumar) - Make minor improvements in the generic power domains (genpd), OPP and system suspend frameworks and in the PM core (Aditya Pakki, Douglas Anderson, Greg Kroah-Hartman, Rafael Wysocki, Yangtao Li)" * tag 'pm-5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (80 commits) cpufreq: kryo: Release OPP tables on module removal cpufreq: ap806: add missing of_node_put after of_device_is_available cpufreq: acpi-cpufreq: Report if CPU doesn't support boost technologies cpufreq: Pass updated policy to driver ->setpolicy() callback cpufreq: Fix two debug messages in cpufreq_set_policy() cpufreq: Reorder and simplify cpufreq_update_policy() cpufreq: Add kerneldoc comments for two core functions PM / core: Add support to skip power management in device/driver model cpufreq: intel_pstate: Rework iowait boosting to be less aggressive cpufreq: intel_pstate: Eliminate intel_pstate_get_base_pstate() cpufreq: intel_pstate: Avoid redundant initialization of local vars powercap/intel_rapl: add Ice Lake mobile ACPI / processor: Set P_LVL{2,3} idle state descriptions cpufreq / cppc: Work around for Hisilicon CPPC cpufreq ACPI / CPPC: Add a helper to get desired performance cpufreq: davinci: move configuration to include/linux/platform_data cpufreq: speedstep: convert BUG() to BUG_ON() cpufreq: powernv: fix missing check of return value in init_powernv_pstates() cpufreq: longhaul: remove unneeded semicolon cpufreq: pcc-cpufreq: remove unneeded semicolon ..
Diffstat (limited to 'drivers/cpuidle')
-rw-r--r--drivers/cpuidle/Kconfig11
-rw-r--r--drivers/cpuidle/dt_idle_states.c15
-rw-r--r--drivers/cpuidle/governors/Makefile1
-rw-r--r--drivers/cpuidle/governors/teo.c444
4 files changed, 464 insertions, 7 deletions
diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
index 7e48eb5bf0a7..8caccbbd7353 100644
--- a/drivers/cpuidle/Kconfig
+++ b/drivers/cpuidle/Kconfig
@@ -4,7 +4,7 @@ config CPU_IDLE
bool "CPU idle PM support"
default y if ACPI || PPC_PSERIES
select CPU_IDLE_GOV_LADDER if (!NO_HZ && !NO_HZ_IDLE)
- select CPU_IDLE_GOV_MENU if (NO_HZ || NO_HZ_IDLE)
+ select CPU_IDLE_GOV_MENU if (NO_HZ || NO_HZ_IDLE) && !CPU_IDLE_GOV_TEO
help
CPU idle is a generic framework for supporting software-controlled
idle processor power management. It includes modular cross-platform
@@ -23,6 +23,15 @@ config CPU_IDLE_GOV_LADDER
config CPU_IDLE_GOV_MENU
bool "Menu governor (for tickless system)"
+config CPU_IDLE_GOV_TEO
+ bool "Timer events oriented (TEO) governor (for tickless systems)"
+ help
+ This governor implements a simplified idle state selection method
+ focused on timer events and does not do any interactivity boosting.
+
+ Some workloads benefit from using it and it generally should be safe
+ to use. Say Y here if you are not happy with the alternatives.
+
config DT_IDLE_STATES
bool
diff --git a/drivers/cpuidle/dt_idle_states.c b/drivers/cpuidle/dt_idle_states.c
index 53342b7f1010..add9569636b5 100644
--- a/drivers/cpuidle/dt_idle_states.c
+++ b/drivers/cpuidle/dt_idle_states.c
@@ -22,16 +22,12 @@
#include "dt_idle_states.h"
static int init_state_node(struct cpuidle_state *idle_state,
- const struct of_device_id *matches,
+ const struct of_device_id *match_id,
struct device_node *state_node)
{
int err;
- const struct of_device_id *match_id;
const char *desc;
- match_id = of_match_node(matches, state_node);
- if (!match_id)
- return -ENODEV;
/*
* CPUidle drivers are expected to initialize the const void *data
* pointer of the passed in struct of_device_id array to the idle
@@ -160,6 +156,7 @@ int dt_init_idle_driver(struct cpuidle_driver *drv,
{
struct cpuidle_state *idle_state;
struct device_node *state_node, *cpu_node;
+ const struct of_device_id *match_id;
int i, err = 0;
const cpumask_t *cpumask;
unsigned int state_idx = start_idx;
@@ -180,6 +177,12 @@ int dt_init_idle_driver(struct cpuidle_driver *drv,
if (!state_node)
break;
+ match_id = of_match_node(matches, state_node);
+ if (!match_id) {
+ err = -ENODEV;
+ break;
+ }
+
if (!of_device_is_available(state_node)) {
of_node_put(state_node);
continue;
@@ -198,7 +201,7 @@ int dt_init_idle_driver(struct cpuidle_driver *drv,
}
idle_state = &drv->states[state_idx++];
- err = init_state_node(idle_state, matches, state_node);
+ err = init_state_node(idle_state, match_id, state_node);
if (err) {
pr_err("Parsing idle state node %pOF failed with err %d\n",
state_node, err);
diff --git a/drivers/cpuidle/governors/Makefile b/drivers/cpuidle/governors/Makefile
index 1b512722689f..4d8aff5248a8 100644
--- a/drivers/cpuidle/governors/Makefile
+++ b/drivers/cpuidle/governors/Makefile
@@ -4,3 +4,4 @@
obj-$(CONFIG_CPU_IDLE_GOV_LADDER) += ladder.o
obj-$(CONFIG_CPU_IDLE_GOV_MENU) += menu.o
+obj-$(CONFIG_CPU_IDLE_GOV_TEO) += teo.o
diff --git a/drivers/cpuidle/governors/teo.c b/drivers/cpuidle/governors/teo.c
new file mode 100644
index 000000000000..7d05efdbd3c6
--- /dev/null
+++ b/drivers/cpuidle/governors/teo.c
@@ -0,0 +1,444 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Timer events oriented CPU idle governor
+ *
+ * Copyright (C) 2018 Intel Corporation
+ * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+ *
+ * The idea of this governor is based on the observation that on many systems
+ * timer events are two or more orders of magnitude more frequent than any
+ * other interrupts, so they are likely to be the most significant source of CPU
+ * wakeups from idle states. Moreover, information about what happened in the
+ * (relatively recent) past can be used to estimate whether or not the deepest
+ * idle state with target residency within the time to the closest timer is
+ * likely to be suitable for the upcoming idle time of the CPU and, if not, then
+ * which of the shallower idle states to choose.
+ *
+ * Of course, non-timer wakeup sources are more important in some use cases and
+ * they can be covered by taking a few most recent idle time intervals of the
+ * CPU into account. However, even in that case it is not necessary to consider
+ * idle duration values greater than the time till the closest timer, as the
+ * patterns that they may belong to produce average values close enough to
+ * the time till the closest timer (sleep length) anyway.
+ *
+ * Thus this governor estimates whether or not the upcoming idle time of the CPU
+ * is likely to be significantly shorter than the sleep length and selects an
+ * idle state for it in accordance with that, as follows:
+ *
+ * - Find an idle state on the basis of the sleep length and state statistics
+ * collected over time:
+ *
+ * o Find the deepest idle state whose target residency is less than or equal
+ * to the sleep length.
+ *
+ * o Select it if it matched both the sleep length and the observed idle
+ * duration in the past more often than it matched the sleep length alone
+ * (i.e. the observed idle duration was significantly shorter than the sleep
+ * length matched by it).
+ *
+ * o Otherwise, select the shallower state with the greatest matched "early"
+ * wakeups metric.
+ *
+ * - If the majority of the most recent idle duration values are below the
+ * target residency of the idle state selected so far, use those values to
+ * compute the new expected idle duration and find an idle state matching it
+ * (which has to be shallower than the one selected so far).
+ */
+
+#include <linux/cpuidle.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/sched/clock.h>
+#include <linux/tick.h>
+
+/*
+ * The PULSE value is added to metrics when they grow and the DECAY_SHIFT value
+ * is used for decreasing metrics on a regular basis.
+ */
+#define PULSE 1024
+#define DECAY_SHIFT 3
+
+/*
+ * Number of the most recent idle duration values to take into consideration for
+ * the detection of wakeup patterns.
+ */
+#define INTERVALS 8
+
+/**
+ * struct teo_idle_state - Idle state data used by the TEO cpuidle governor.
+ * @early_hits: "Early" CPU wakeups "matching" this state.
+ * @hits: "On time" CPU wakeups "matching" this state.
+ * @misses: CPU wakeups "missing" this state.
+ *
+ * A CPU wakeup is "matched" by a given idle state if the idle duration measured
+ * after the wakeup is between the target residency of that state and the target
+ * residency of the next one (or if this is the deepest available idle state, it
+ * "matches" a CPU wakeup when the measured idle duration is at least equal to
+ * its target residency).
+ *
+ * Also, from the TEO governor perspective, a CPU wakeup from idle is "early" if
+ * it occurs significantly earlier than the closest expected timer event (that
+ * is, early enough to match an idle state shallower than the one matching the
+ * time till the closest timer event). Otherwise, the wakeup is "on time", or
+ * it is a "hit".
+ *
+ * A "miss" occurs when the given state doesn't match the wakeup, but it matches
+ * the time till the closest timer event used for idle state selection.
+ */
+struct teo_idle_state {
+ unsigned int early_hits;
+ unsigned int hits;
+ unsigned int misses;
+};
+
+/**
+ * struct teo_cpu - CPU data used by the TEO cpuidle governor.
+ * @time_span_ns: Time between idle state selection and post-wakeup update.
+ * @sleep_length_ns: Time till the closest timer event (at the selection time).
+ * @states: Idle states data corresponding to this CPU.
+ * @last_state: Idle state entered by the CPU last time.
+ * @interval_idx: Index of the most recent saved idle interval.
+ * @intervals: Saved idle duration values.
+ */
+struct teo_cpu {
+ u64 time_span_ns;
+ u64 sleep_length_ns;
+ struct teo_idle_state states[CPUIDLE_STATE_MAX];
+ int last_state;
+ int interval_idx;
+ unsigned int intervals[INTERVALS];
+};
+
+static DEFINE_PER_CPU(struct teo_cpu, teo_cpus);
+
+/**
+ * teo_update - Update CPU data after wakeup.
+ * @drv: cpuidle driver containing state data.
+ * @dev: Target CPU.
+ */
+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;
+
+ if (cpu_data->time_span_ns >= cpu_data->sleep_length_ns) {
+ /*
+ * One of the safety nets has triggered or this was a timer
+ * wakeup (or equivalent).
+ */
+ measured_us = sleep_length_us;
+ } else {
+ unsigned int lat = drv->states[cpu_data->last_state].exit_latency;
+
+ measured_us = ktime_to_us(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;
+ else
+ measured_us /= 2;
+ }
+
+ /*
+ * Decay the "early hits" metric for all of the states and find the
+ * states matching the sleep length and the measured idle duration.
+ */
+ for (i = 0; i < drv->state_count; i++) {
+ unsigned int early_hits = cpu_data->states[i].early_hits;
+
+ cpu_data->states[i].early_hits -= early_hits >> DECAY_SHIFT;
+
+ if (drv->states[i].target_residency <= sleep_length_us) {
+ idx_timer = i;
+ if (drv->states[i].target_residency <= measured_us)
+ idx_hit = i;
+ }
+ }
+
+ /*
+ * Update the "hits" and "misses" data for the state matching the sleep
+ * length. If it matches the measured idle duration too, this is a hit,
+ * so increase the "hits" metric for it then. Otherwise, this is a
+ * miss, so increase the "misses" metric for it. In the latter case
+ * also increase the "early hits" metric for the state that actually
+ * matches the measured idle duration.
+ */
+ if (idx_timer >= 0) {
+ unsigned int hits = cpu_data->states[idx_timer].hits;
+ unsigned int misses = cpu_data->states[idx_timer].misses;
+
+ hits -= hits >> DECAY_SHIFT;
+ misses -= misses >> DECAY_SHIFT;
+
+ if (idx_timer > idx_hit) {
+ misses += PULSE;
+ if (idx_hit >= 0)
+ cpu_data->states[idx_hit].early_hits += PULSE;
+ } else {
+ hits += PULSE;
+ }
+
+ cpu_data->states[idx_timer].misses = misses;
+ cpu_data->states[idx_timer].hits = hits;
+ }
+
+ /*
+ * If the total time span between idle state selection and the "reflect"
+ * callback is greater than or equal to the sleep length determined at
+ * the idle state selection time, the wakeup is likely to be due to a
+ * timer event.
+ */
+ if (cpu_data->time_span_ns >= cpu_data->sleep_length_ns)
+ measured_us = UINT_MAX;
+
+ /*
+ * Save idle duration values corresponding to non-timer wakeups for
+ * pattern detection.
+ */
+ cpu_data->intervals[cpu_data->interval_idx++] = measured_us;
+ if (cpu_data->interval_idx > INTERVALS)
+ cpu_data->interval_idx = 0;
+}
+
+/**
+ * teo_find_shallower_state - Find shallower idle state matching given duration.
+ * @drv: cpuidle driver containing state data.
+ * @dev: Target CPU.
+ * @state_idx: Index of the capping idle state.
+ * @duration_us: 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)
+{
+ int i;
+
+ for (i = state_idx - 1; i >= 0; i--) {
+ if (drv->states[i].disabled || dev->states_usage[i].disable)
+ continue;
+
+ state_idx = i;
+ if (drv->states[i].target_residency <= duration_us)
+ break;
+ }
+ return state_idx;
+}
+
+/**
+ * teo_select - Selects the next idle state to enter.
+ * @drv: cpuidle driver containing state data.
+ * @dev: Target CPU.
+ * @stop_tick: Indication on whether or not to stop the scheduler tick.
+ */
+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, count;
+ int max_early_idx, idx, i;
+ ktime_t delta_tick;
+
+ if (cpu_data->last_state >= 0) {
+ teo_update(drv, dev);
+ cpu_data->last_state = -1;
+ }
+
+ 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);
+
+ count = 0;
+ max_early_idx = -1;
+ idx = -1;
+
+ 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) {
+ /*
+ * If the "early hits" metric of a disabled state is
+ * greater than the current maximum, it should be taken
+ * into account, because it would be a mistake to select
+ * a deeper state with lower "early hits" metric. The
+ * index cannot be changed to point to it, however, so
+ * just increase the max count alone and let the index
+ * still point to a shallower idle state.
+ */
+ if (max_early_idx >= 0 &&
+ count < cpu_data->states[i].early_hits)
+ count = cpu_data->states[i].early_hits;
+
+ continue;
+ }
+
+ if (idx < 0)
+ idx = i; /* first enabled state */
+
+ if (s->target_residency > duration_us)
+ break;
+
+ if (s->exit_latency > latency_req) {
+ /*
+ * If we break out of the loop for latency reasons, use
+ * the target residency of the selected state as the
+ * expected idle duration to avoid stopping the tick
+ * as long as that target residency is low enough.
+ */
+ duration_us = drv->states[idx].target_residency;
+ goto refine;
+ }
+
+ idx = i;
+
+ if (count < cpu_data->states[i].early_hits &&
+ !(tick_nohz_tick_stopped() &&
+ drv->states[i].target_residency < TICK_USEC)) {
+ count = cpu_data->states[i].early_hits;
+ max_early_idx = i;
+ }
+ }
+
+ /*
+ * If the "hits" metric of the idle state matching the sleep length is
+ * greater than its "misses" metric, that is the one to use. Otherwise,
+ * it is more likely that one of the shallower states will match the
+ * idle duration observed after wakeup, so take the one with the maximum
+ * "early hits" metric, but if that cannot be determined, just use the
+ * state selected so far.
+ */
+ if (cpu_data->states[idx].hits <= cpu_data->states[idx].misses &&
+ max_early_idx >= 0) {
+ idx = max_early_idx;
+ duration_us = drv->states[idx].target_residency;
+ }
+
+refine:
+ if (idx < 0) {
+ idx = 0; /* No states enabled. Must use 0. */
+ } else if (idx > 0) {
+ u64 sum = 0;
+
+ count = 0;
+
+ /*
+ * Count and sum the most recent idle duration values less than
+ * the target residency of the state selected so far, find the
+ * max.
+ */
+ for (i = 0; i < INTERVALS; i++) {
+ unsigned int val = cpu_data->intervals[i];
+
+ if (val >= drv->states[idx].target_residency)
+ continue;
+
+ count++;
+ sum += val;
+ }
+
+ /*
+ * Give up unless the majority of the most recent idle duration
+ * values are in the interesting range.
+ */
+ if (count > INTERVALS / 2) {
+ unsigned int avg_us = 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)) {
+ idx = teo_find_shallower_state(drv, dev, idx, avg_us);
+ duration_us = avg_us;
+ }
+ }
+ }
+
+ /*
+ * Don't stop the tick if the selected state is a polling one or if the
+ * 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);
+
+ *stop_tick = false;
+
+ /*
+ * The tick is not going to be stopped, so if the target
+ * residency of the state to be returned is not within the time
+ * 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);
+ }
+
+ return idx;
+}
+
+/**
+ * teo_reflect - Note that governor data for the CPU need to be updated.
+ * @dev: Target CPU.
+ * @state: Entered state.
+ */
+static void teo_reflect(struct cpuidle_device *dev, int state)
+{
+ struct teo_cpu *cpu_data = per_cpu_ptr(&teo_cpus, dev->cpu);
+
+ cpu_data->last_state = state;
+ /*
+ * If the wakeup was not "natural", but triggered by one of the safety
+ * nets, assume that the CPU might have been idle for the entire sleep
+ * length time.
+ */
+ if (dev->poll_time_limit ||
+ (tick_nohz_idle_got_tick() && cpu_data->sleep_length_ns > TICK_NSEC)) {
+ dev->poll_time_limit = false;
+ cpu_data->time_span_ns = cpu_data->sleep_length_ns;
+ } else {
+ cpu_data->time_span_ns = local_clock() - cpu_data->time_span_ns;
+ }
+}
+
+/**
+ * teo_enable_device - Initialize the governor's data for the target CPU.
+ * @drv: cpuidle driver (not used).
+ * @dev: Target CPU.
+ */
+static int teo_enable_device(struct cpuidle_driver *drv,
+ struct cpuidle_device *dev)
+{
+ struct teo_cpu *cpu_data = per_cpu_ptr(&teo_cpus, dev->cpu);
+ int i;
+
+ memset(cpu_data, 0, sizeof(*cpu_data));
+
+ for (i = 0; i < INTERVALS; i++)
+ cpu_data->intervals[i] = UINT_MAX;
+
+ return 0;
+}
+
+static struct cpuidle_governor teo_governor = {
+ .name = "teo",
+ .rating = 19,
+ .enable = teo_enable_device,
+ .select = teo_select,
+ .reflect = teo_reflect,
+};
+
+static int __init teo_governor_init(void)
+{
+ return cpuidle_register_governor(&teo_governor);
+}
+
+postcore_initcall(teo_governor_init);