| /linux/Documentation/devicetree/bindings/powerpc/opal/ |
| H A D | power-mgt.txt | 1 IBM Power-Management Bindings
5 idle states. The description of these idle states is exposed via the
6 node @power-mgt in the device-tree by the firmware.
9 ----------------
10 Typically each idle state has the following associated properties:
12 - name: The name of the idle state as defined by the firmware.
14 - flags: indicating some aspects of this idle states such as the
15 extent of state-loss, whether timebase is stopped on this
16 idle states and so on. The flag bits are as follows:
18 - exit-latency: The latency involved in transitioning the state of the
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| /linux/Documentation/admin-guide/pm/ |
| H A D | cpuidle.rst | 1 .. SPDX-License-Identifier: GPL-2.0
8 CPU Idle Time Management
21 memory or executed. Those states are the *idle* states of the processor.
23 Since part of the processor hardware is not used in idle states, entering them
27 CPU idle time management is an energy-efficiency feature concerned about using
28 the idle states of processors for this purpose.
31 ------------
33 CPU idle time management operates on CPUs as seen by the *CPU scheduler* (that
37 software as individual single-core processors. In other words, a CPU is an
44 enter an idle state, that applies to the processor as a whole.
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| H A D | intel_idle.rst | 1 .. SPDX-License-Identifier: GPL-2.0
5 ``intel_idle`` CPU Idle Time Management Driver
17 :doc:`CPU idle time management subsystem <cpuidle>` in the Linux kernel
18 (``CPUIdle``). It is the default CPU idle time management driver for the
24 Documentation/admin-guide/pm/cpuidle.rst if you have not done that yet.]
27 logical CPU executing it is idle and so it may be possible to put some of the
28 processor's functional blocks into low-power states. That instruction takes two
38 only way to pass early-configuration-time parameters to it is via the kernel
42 .. _intel-idle-enumeration-of-states:
44 Enumeration of Idle States
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| H A D | suspend-flows.rst | 1 .. SPDX-License-Identifier: GPL-2.0
12 At least one global system-wide transition needs to be carried out for the
13 system to get from the working state into one of the supported
14 :doc:`sleep states <sleep-states>`. Hibernation requires more than one
16 referred to as *system-wide suspend* (or simply *system suspend*) states, need
19 For those sleep states, the transition from the working state of the system into
20 the target sleep state is referred to as *system suspend* too (in the majority
21 of cases, whether this means a transition or a sleep state of the system should
22 be clear from the context) and the transition back from the sleep state into the
23 working state is referred to as *system resume*.
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| /linux/Documentation/devicetree/bindings/cpu/ |
| H A D | idle-states.yaml | 1 # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
3 ---
4 $id: http://devicetree.org/schemas/cpu/idle-states.yaml#
5 $schema: http://devicetree.org/meta-schemas/core.yaml#
7 title: Idle states
10 - Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
11 - Anup Patel <anup@brainfault.org>
15 1 - Introduction
18 ARM and RISC-V systems contain HW capable of managing power consumption
19 dynamically, where cores can be put in different low-power states (ranging
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| /linux/drivers/cpuidle/governors/ |
| H A D | teo.c | 1 // SPDX-License-Identifier: GPL-2.0
3 * Timer events oriented CPU idle governor
5 * Copyright (C) 2018 - 2021 Intel Corporation
10 * DOC: teo-description
15 * wakeups from idle states. Moreover, information about what happened in the
17 * idle state with target residency within the (known) time till the closest
19 * the upcoming CPU idle period and, if not, then which of the shallower idle
22 * Of course, non-timer wakeup sources are more important in some use cases
23 * which can be covered by taking a few most recent idle time intervals of the
25 * consider idle duration values greater than the sleep length, because the
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| /linux/drivers/thermal/ |
| H A D | cpuidle_cooling.c | 1 // SPDX-License-Identifier: GPL-2.0
21 * struct cpuidle_cooling_device - data for the idle cooling device
22 * @ii_dev: an atomic to keep track of the last task exiting the idle cycle
23 * @state: a normalized integer giving the state of the cooling device
27 unsigned long state; member
31 * cpuidle_cooling_runtime - Running time computation
32 * @idle_duration_us: CPU idle time to inject in microseconds
33 * @state: a percentile based number
35 * The running duration is computed from the idle injection duration
36 * which is fixed. If we reach 100% of idle injection ratio, that
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| /linux/Documentation/driver-api/pm/ |
| H A D | cpuidle.rst | 1 .. SPDX-License-Identifier: GPL-2.0
5 CPU Idle Time Management
13 CPU Idle Time Management Subsystem
18 cores) is idle after an interrupt or equivalent wakeup event, which means that
19 there are no tasks to run on it except for the special "idle" task associated
21 belongs to. That can be done by making the idle logical CPU stop fetching
23 depended on by it into an idle state in which they will draw less power.
25 However, there may be multiple different idle states that can be used in such a
28 particular idle state. That is the role of the CPU idle time management
35 units: *governors* responsible for selecting idle states to ask the processor
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| /linux/Documentation/devicetree/bindings/mux/ |
| H A D | mux-controller.yaml | 1 # SPDX-License-Identifier: GPL-2.0
3 ---
4 $id: http://devicetree.org/schemas/mux/mux-controller.yaml#
5 $schema: http://devicetree.org/meta-schemas/core.yaml#
10 - Peter Rosin <peda@axentia.se>
19 A mux controller provides a number of states to its consumers, and the state
20 space is a simple zero-based enumeration. I.e. 0-1 for a 2-way multiplexer,
21 0-7 for an 8-way multiplexer, etc.
25 --------------------
28 specifier using the '#mux-control-cells' or '#mux-state-cells' property.
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| /linux/tools/power/cpupower/man/ |
| H A D | cpupower-idle-info.1 | 1 .TH "CPUPOWER-IDLE-INFO" "1" "0.1" "" "cpupower Manual"
4 cpupower\-idle\-info \- Utility to retrieve cpu idle kernel information
7 cpupower [ \-c cpulist ] idle\-info [\fIoptions\fP]
10 A tool which prints out per cpu idle information helpful to developers and interested users.
14 \fB\-f\fR \fB\-\-silent\fR
15 Only print a summary of all available C-states in the system.
17 \fB\-e\fR \fB\-\-proc\fR
19 Prints out idle information in old /proc/acpi/processor/*/power format. This
23 .SH IDLE\-INFO DESCRIPTIONS
24 CPU sleep state statistics and descriptions are retrieved from sysfs files,
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| H A D | cpupower-idle-set.1 | 1 .TH "CPUPOWER-IDLE-SET" "1" "0.1" "" "cpupower Manual"
4 cpupower\-idle\-set \- Utility to set cpu idle state specific kernel options
7 cpupower [ \-c cpulist ] idle\-set [\fIoptions\fP]
10 The cpupower idle\-set subcommand allows to set cpu idle, also called cpu
11 sleep state, specific options offered by the kernel. One example is disabling
16 \fB\-d\fR \fB\-\-disable\fR <STATE_NO>
17 Disable a specific processor sleep state.
19 \fB\-e\fR \fB\-\-enable\fR <STATE_NO>
20 Enable a specific processor sleep state.
22 \fB\-D\fR \fB\-\-disable-by-latency\fR <LATENCY>
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| H A D | cpupower-monitor.1 | 1 .TH CPUPOWER\-MONITOR "1" "22/02/2011" "" "cpupower Manual"
3 cpupower\-monitor \- Report processor frequency and idle statistics
7 .RB "\-l"
10 .RB [ -c ] [ "\-m <mon1>," [ "<mon2>,..." ] ]
11 .RB [ "\-i seconds" ]
14 .RB [ -c ][ "\-m <mon1>," [ "<mon2>,..." ] ]
18 \fBcpupower-monitor \fP reports processor topology, frequency and idle power
19 state statistics. Either \fBcommand\fP is forked and
22 \fBcpupower-monitor \fP implements independent processor sleep state and
24 directly reading out hardware registers. Use \-l to get an overview which are
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| /linux/Documentation/devicetree/bindings/power/ |
| H A D | domain-idle-state.yaml | 1 # SPDX-License-Identifier: GPL-2.0
3 ---
4 $id: http://devicetree.org/schemas/power/domain-idle-state.yaml#
5 $schema: http://devicetree.org/meta-schemas/core.yaml#
7 title: PM Domain Idle States
10 - Ulf Hansson <ulf.hansson@linaro.org>
13 A domain idle state node represents the state parameters that will be used to
14 select the state when there are no active components in the PM domain.
18 const: domain-idle-states
21 "^(cpu|cluster|domain)-":
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| /linux/Documentation/driver-api/thermal/ |
| H A D | cpu-idle-cooling.rst | 1 .. SPDX-License-Identifier: GPL-2.0
4 CPU Idle Cooling
8 ----------
26 budget lower than the requested one and under-utilize the CPU, thus
27 losing performance. In other words, one OPP under-utilizes the CPU
33 ----------
37 decrease. Acting on the idle state duration or the idle cycle
47 At a specific OPP, we can assume that injecting idle cycle on all CPUs
49 idle state target residency, we lead to dropping the static and the
51 this state). So the sustainable power with idle cycles has a linear
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| /linux/drivers/cpuidle/ |
| H A D | coupled.c | 1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * coupled.c - helper functions to enter the same idle state on multiple cpus
27 * will corrupt the gic state unless the other cpu runs a work
28 * around). Each cpu has a power state that it can enter without
32 * sometimes the whole SoC). Entering a coupled power state must
36 * WFI state until all cpus are ready to enter a coupled state, at
37 * which point the coupled state function will be called on all
40 * Once all cpus are ready to enter idle, they are woken by an smp
42 * cpus will find work to do, and choose not to enter idle. A
44 * power state enter function at the same time. During this pass,
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| H A D | dt_idle_states.c | 1 // SPDX-License-Identifier: GPL-2.0-only
3 * DT idle states parsing code.
9 #define pr_fmt(fmt) "DT idle-states: " fmt
29 * pointer of the passed in struct of_device_id array to the idle in init_state_node()
30 * state enter function. in init_state_node()
32 idle_state->enter = match_id->data; in init_state_node()
34 * Since this is not a "coupled" state, it's safe to assume interrupts in init_state_node()
38 idle_state->enter_s2idle = match_id->data; in init_state_node()
40 err = of_property_read_u32(state_node, "wakeup-latency-us", in init_state_node()
41 &idle_state->exit_latency); in init_state_node()
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| H A D | cpuidle-arm.c | 1 // SPDX-License-Identifier: GPL-2.0-only
3 * ARM/ARM64 generic CPU idle driver.
25 * arm_enter_idle_state - Programs CPU to enter the specified state
29 * idx: state index
32 * specified target state selected by the governor.
38 * Pass idle state index to arm_cpuidle_suspend which in turn in arm_enter_idle_state()
39 * will call the CPU ops suspend protocol with idle index as a in arm_enter_idle_state()
49 * State at index 0 is standby wfi and considered standard
51 * can't be used as "state 0", DT bindings must be implemented
53 * handler for idle state index 0.
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| H A D | cpuidle.c | 2 * cpuidle.c - core cpuidle infrastructure
4 * (C) 2006-2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
11 #include "linux/percpu-defs.h"
17 #include <linux/sched/idle.h>
55 return off || !initialized || !drv || !dev || !dev->enabled; in cpuidle_not_available()
59 * cpuidle_play_dead - cpu off-lining
70 return -ENODEV; in cpuidle_play_dead()
72 /* Find lowest-power state that supports long-term idle */ in cpuidle_play_dead()
73 for (i = drv->state_count - 1; i >= 0; i--) in cpuidle_play_dead()
74 if (drv->states[i].enter_dead) in cpuidle_play_dead()
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| /linux/kernel/ |
| H A D | context_tracking.c | 1 // SPDX-License-Identifier: GPL-2.0-only
4 * userspace, guest or idle.
7 * runs in idle, userspace or guest mode.
13 * Many thanks to Gilad Ben-Yossef, Paul McKenney, Ingo Molnar, Andrew Morton,
16 * RCU extended quiescent state bits imported from kernel/rcu/tree.c
34 .state = ATOMIC_INIT(CT_RCU_WATCHING),
41 /* Record the current task on exiting RCU-tasks (dyntick-idle entry). */
45 WRITE_ONCE(current->rcu_tasks_idle_cpu, smp_processor_id()); in rcu_task_exit()
49 /* Record no current task on entering RCU-tasks (dyntick-idle exit). */
53 WRITE_ONCE(current->rcu_tasks_idle_cpu, -1); in rcu_task_enter()
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| /linux/arch/powerpc/platforms/powernv/ |
| H A D | idle.c | 1 // SPDX-License-Identifier: GPL-2.0-or-later
21 #include <asm/code-patching.h>
29 /* Power ISA 3.0 allows for stop states 0x0 - 0xF */
40 * The default stop state that will be used by ppc_md.power_save
48 * First stop state levels when SPR and TB loss can occur.
54 * psscr value and mask of the deepest stop idle state.
165 * Used to store fastsleep workaround state
166 * 0 - Workaround applied/undone at fastsleep entry/exit path (Default)
167 * 1 - Workaround applied once, never undone.
185 return -EINVAL; in store_fastsleep_workaround_applyonce()
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| /linux/Documentation/admin-guide/thermal/ |
| H A D | intel_powerclamp.rst | 6 - Arjan van de Ven <arjan@linux.intel.com>
7 - Jacob Pan <jacob.jun.pan@linux.intel.com>
12 - Goals and Objectives
15 - Idle Injection
16 - Calibration
19 - Effectiveness and Limitations
20 - Power vs Performance
21 - Scalability
22 - Calibration
23 - Comparison with Alternative Techniques
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| /linux/kernel/time/ |
| H A D | timer_migration.c | 1 // SPDX-License-Identifier: GPL-2.0-only
15 #include "tick-internal.h"
34 * GRP0:0 - GRP0:2 GRP0:3 - GRP0:5
37 * CPUS 0-7 8-15 16-23 24-31 32-39 40-47
40 * queues are updated when CPUs go in idle. When they come out of idle
54 * from the idle CPU and runs the timer function. After that it updates the
57 * CPUs which go idle arm their CPU local timer hardware for the next local
62 * in the LVL0 group. In both cases the CPU marks itself idle in the LVL0
65 * When CPU comes out of idle and when a group has at least a single active
79 * When the last CPU in the system goes idle, then it drops all migrator
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| /linux/kernel/sched/ |
| H A D | idle.c | 1 // SPDX-License-Identifier: GPL-2.0-only
3 * Generic entry points for the idle threads and
4 * implementation of the idle task scheduling class.
14 * sched_idle_set_state - Record idle state for the current CPU.
15 * @idle_state: State to record.
29 cpu_idle_force_poll--; in cpu_idle_poll_ctrl()
104 * default_idle_call - Default CPU idle routine.
132 return -EBUSY; in call_cpuidle_s2idle()
141 * The idle task must be scheduled, it is pointless to go to idle, just in call_cpuidle()
142 * update no idle residency and return. in call_cpuidle()
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| /linux/Documentation/devicetree/bindings/thermal/ |
| H A D | thermal-idle.yaml | 1 # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
4 ---
5 $id: http://devicetree.org/schemas/thermal/thermal-idle.yaml#
6 $schema: http://devicetree.org/meta-schemas/core.yaml#
8 title: Thermal idle cooling device
11 - Daniel Lezcano <daniel.lezcano@linaro.org>
14 The thermal idle cooling device allows the system to passively
15 mitigate the temperature on the device by injecting idle cycles,
18 This binding describes the thermal idle node.
22 const: thermal-idle
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| /linux/Documentation/devicetree/bindings/i2c/ |
| H A D | i2c-mux-pinctrl.yaml | 1 # SPDX-License-Identifier: GPL-2.0-only
3 ---
4 $id: http://devicetree.org/schemas/i2c/i2c-mux-pinctrl.yaml#
5 $schema: http://devicetree.org/meta-schemas/core.yaml#
7 title: Pinctrl-based I2C Bus Mux
10 - Wolfram Sang <wsa@kernel.org>
17 +-----+ +-----+
19 +------------------------+ +-----+ +-----+
21 | /----|------+--------+
22 | +---+ +------+ | child bus A, on first set of pins
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