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docs: thermal: convert to ReST

Browse Source 
Rename the thermal documentation files to ReST, add an
index for them and adjust in order to produce a nice html
output via the Sphinx build system.

At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
This commit is contained in:
Mauro Carvalho Chehab
2019-06-27 21:22:15 +08:00
committed by Zhang Rui
parent 57c5b2ec90
commit 6bbe6f5732
12 changed files with 695 additions and 430 deletions
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Documentation/thermal/cpu-cooling-api.txt → Documentation/thermal/cpu-cooling-api.rst
+27 -12
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@@ -1,5 +1,6 @@
=======================
CPU cooling APIs How To
===================================
=======================
Written by Amit Daniel Kachhap <amit.kachhap@linaro.org>
@@ -8,40 +9,54 @@ Updated: 6 Jan 2015
Copyright (c) 2012 Samsung Electronics Co., Ltd(http://www.samsung.com)
0. Introduction
===============
The generic cpu cooling(freq clipping) provides registration/unregistration APIs
to the caller. The binding of the cooling devices to the trip point is left for
the user. The registration APIs returns the cooling device pointer.
1. cpu cooling APIs
===================
1.1 cpufreq registration/unregistration APIs
1.1.1 struct thermal_cooling_device *cpufreq_cooling_register(
struct cpumask *clip_cpus)
--------------------------------------------
::
struct thermal_cooling_device
*cpufreq_cooling_register(struct cpumask *clip_cpus)
This interface function registers the cpufreq cooling device with the name
"thermal-cpufreq-%x". This api can support multiple instances of cpufreq
cooling devices.
clip_cpus: cpumask of cpus where the frequency constraints will happen.
clip_cpus:
cpumask of cpus where the frequency constraints will happen.
1.1.2 struct thermal_cooling_device *of_cpufreq_cooling_register(
struct cpufreq_policy *policy)
::
struct thermal_cooling_device
*of_cpufreq_cooling_register(struct cpufreq_policy *policy)
This interface function registers the cpufreq cooling device with
the name "thermal-cpufreq-%x" linking it with a device tree node, in
order to bind it via the thermal DT code. This api can support multiple
instances of cpufreq cooling devices.
policy: CPUFreq policy.
policy:
CPUFreq policy.
1.1.3 void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
::
void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
This interface function unregisters the "thermal-cpufreq-%x" cooling device.
cdev: Cooling device pointer which has to be unregistered.
2. Power models
===============
The power API registration functions provide a simple power model for
CPUs. The current power is calculated as dynamic power (static power isn't
@@ -65,9 +80,9 @@ For a given processor implementation the primary factors are:
variation. In pathological cases this variation can be significant,
but typically it is of a much lesser impact than the factors above.
A high level dynamic power consumption model may then be represented as:
A high level dynamic power consumption model may then be represented as::
Pdyn = f(run) * Voltage^2 * Frequency * Utilisation
Pdyn = f(run) * Voltage^2 * Frequency * Utilisation
f(run) here represents the described execution behaviour and its
result has a units of Watts/Hz/Volt^2 (this often expressed in
@@ -80,9 +95,9 @@ factors. Therefore, in initial implementation that contribution is
represented as a constant coefficient. This is a simplification
consistent with the relative contribution to overall power variation.
In this simplified representation our model becomes:
In this simplified representation our model becomes::
Pdyn = Capacitance * Voltage^2 * Frequency * Utilisation
Pdyn = Capacitance * Voltage^2 * Frequency * Utilisation
Where `capacitance` is a constant that represents an indicative
running time dynamic power coefficient in fundamental units of
Documentation/thermal/exynos_thermal → Documentation/thermal/exynos_thermal.rst
+30 -17
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@@ -1,8 +1,11 @@
========================
Kernel driver exynos_tmu
=================
========================
Supported chips:
* ARM SAMSUNG EXYNOS4, EXYNOS5 series of SoC
Datasheet: Not publicly available
Authors: Donggeun Kim <dg77.kim@samsung.com>
@@ -19,32 +22,39 @@ Temperature can be taken from the temperature code.
There are three equations converting from temperature to temperature code.
The three equations are:
1. Two point trimming
1. Two point trimming::
Tc = (T - 25) * (TI2 - TI1) / (85 - 25) + TI1
2. One point trimming
2. One point trimming::
Tc = T + TI1 - 25
3. No trimming
3. No trimming::
Tc = T + 50
Tc: Temperature code, T: Temperature,
TI1: Trimming info for 25 degree Celsius (stored at TRIMINFO register)
Tc:
Temperature code, T: Temperature,
TI1:
Trimming info for 25 degree Celsius (stored at TRIMINFO register)
Temperature code measured at 25 degree Celsius which is unchanged
TI2: Trimming info for 85 degree Celsius (stored at TRIMINFO register)
TI2:
Trimming info for 85 degree Celsius (stored at TRIMINFO register)
Temperature code measured at 85 degree Celsius which is unchanged
TMU(Thermal Management Unit) in EXYNOS4/5 generates interrupt
when temperature exceeds pre-defined levels.
The maximum number of configurable threshold is five.
The threshold levels are defined as follows:
The threshold levels are defined as follows::
Level_0: current temperature > trigger_level_0 + threshold
Level_1: current temperature > trigger_level_1 + threshold
Level_2: current temperature > trigger_level_2 + threshold
Level_3: current temperature > trigger_level_3 + threshold
The threshold and each trigger_level are set
through the corresponding registers.
The threshold and each trigger_level are set
through the corresponding registers.
When an interrupt occurs, this driver notify kernel thermal framework
with the function exynos_report_trigger.
@@ -54,24 +64,27 @@ it can be used to synchronize the cooling action.
TMU driver description:
-----------------------
The exynos thermal driver is structured as,
The exynos thermal driver is structured as::
Kernel Core thermal framework
(thermal_core.c, step_wise.c, cpu_cooling.c)
^
|
|
TMU configuration data -------> TMU Driver <------> Exynos Core thermal wrapper
(exynos_tmu_data.c) (exynos_tmu.c) (exynos_thermal_common.c)
(exynos_tmu_data.h) (exynos_tmu.h) (exynos_thermal_common.h)
TMU configuration data -----> TMU Driver <----> Exynos Core thermal wrapper
(exynos_tmu_data.c) (exynos_tmu.c) (exynos_thermal_common.c)
(exynos_tmu_data.h) (exynos_tmu.h) (exynos_thermal_common.h)
a) TMU configuration data: This consist of TMU register offsets/bitfields
a) TMU configuration data:
This consist of TMU register offsets/bitfields
described through structure exynos_tmu_registers. Also several
other platform data (struct exynos_tmu_platform_data) members
are used to configure the TMU.
b) TMU driver: This component initialises the TMU controller and sets different
b) TMU driver:
This component initialises the TMU controller and sets different
thresholds. It invokes core thermal implementation with the call
exynos_report_trigger.
c) Exynos Core thermal wrapper: This provides 3 wrapper function to use the
c) Exynos Core thermal wrapper:
This provides 3 wrapper function to use the
Kernel core thermal framework. They are exynos_unregister_thermal,
exynos_register_thermal and exynos_report_trigger.
Documentation/thermal/exynos_thermal_emulation
-53
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@@ -1,53 +0,0 @@
EXYNOS EMULATION MODE
========================
Copyright (C) 2012 Samsung Electronics
Written by Jonghwa Lee <jonghwa3.lee@samsung.com>
Description
-----------
Exynos 4x12 (4212, 4412) and 5 series provide emulation mode for thermal management unit.
Thermal emulation mode supports software debug for TMU's operation. User can set temperature
manually with software code and TMU will read current temperature from user value not from
sensor's value.
Enabling CONFIG_THERMAL_EMULATION option will make this support available.
When it's enabled, sysfs node will be created as
/sys/devices/virtual/thermal/thermal_zone'zone id'/emul_temp.
The sysfs node, 'emul_node', will contain value 0 for the initial state. When you input any
temperature you want to update to sysfs node, it automatically enable emulation mode and
current temperature will be changed into it.
(Exynos also supports user changeable delay time which would be used to delay of
changing temperature. However, this node only uses same delay of real sensing time, 938us.)
Exynos emulation mode requires synchronous of value changing and enabling. It means when you
want to update the any value of delay or next temperature, then you have to enable emulation
mode at the same time. (Or you have to keep the mode enabling.) If you don't, it fails to
change the value to updated one and just use last succeessful value repeatedly. That's why
this node gives users the right to change termerpature only. Just one interface makes it more
simply to use.
Disabling emulation mode only requires writing value 0 to sysfs node.
TEMP 120 |
|
100 |
|
80 |
| +-----------
60 | | |
| +-------------| |
40 | | | |
| | | |
20 | | | +----------
| | | | |
0 |______________|_____________|__________|__________|_________
A A A A TIME
|<----->| |<----->| |<----->| |
| 938us | | | | | |
emulation : 0 50 | 70 | 20 | 0
current temp : sensor 50 70 20 sensor
Documentation/thermal/exynos_thermal_emulation.rst
+61
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@@ -0,0 +1,61 @@
=====================
Exynos Emulation Mode
=====================
Copyright (C) 2012 Samsung Electronics
Written by Jonghwa Lee <jonghwa3.lee@samsung.com>
Description
-----------
Exynos 4x12 (4212, 4412) and 5 series provide emulation mode for thermal
management unit. Thermal emulation mode supports software debug for
TMU's operation. User can set temperature manually with software code
and TMU will read current temperature from user value not from sensor's
value.
Enabling CONFIG_THERMAL_EMULATION option will make this support
available. When it's enabled, sysfs node will be created as
/sys/devices/virtual/thermal/thermal_zone'zone id'/emul_temp.
The sysfs node, 'emul_node', will contain value 0 for the initial state.
When you input any temperature you want to update to sysfs node, it
automatically enable emulation mode and current temperature will be
changed into it.
(Exynos also supports user changeable delay time which would be used to
delay of changing temperature. However, this node only uses same delay
of real sensing time, 938us.)
Exynos emulation mode requires synchronous of value changing and
enabling. It means when you want to update the any value of delay or
next temperature, then you have to enable emulation mode at the same
time. (Or you have to keep the mode enabling.) If you don't, it fails to
change the value to updated one and just use last succeessful value
repeatedly. That's why this node gives users the right to change
termerpature only. Just one interface makes it more simply to use.
Disabling emulation mode only requires writing value 0 to sysfs node.
::
TEMP 120 |
|
100 |
|
80 |
| +-----------
60 | | |
| +-------------| |
40 | | | |
| | | |
20 | | | +----------
| | | | |
0 |______________|_____________|__________|__________|_________
A A A A TIME
|<----->| |<----->| |<----->| |
| 938us | | | | | |
emulation : 0 50 | 70 | 20 | 0
current temp: sensor 50 70 20 sensor
Documentation/thermal/index.rst
+18
View File
@@ -0,0 +1,18 @@
:orphan:
=======
Thermal
=======
.. toctree::
:maxdepth: 1
cpu-cooling-api
sysfs-api
power_allocator
exynos_thermal
exynos_thermal_emulation
intel_powerclamp
nouveau_thermal
x86_pkg_temperature_thermal
Documentation/thermal/intel_powerclamp.txt → Documentation/thermal/intel_powerclamp.rst
+90 -87
View File
@@ -1,10 +1,13 @@
=======================
INTEL POWERCLAMP DRIVER
=======================
By: Arjan van de Ven <arjan@linux.intel.com>
Jacob Pan <jacob.jun.pan@linux.intel.com>
=======================
Intel Powerclamp Driver
=======================
By:
- Arjan van de Ven <arjan@linux.intel.com>
- Jacob Pan <jacob.jun.pan@linux.intel.com>
.. Contents:
Contents:
(*) Introduction
- Goals and Objectives
@@ -23,7 +26,6 @@ Contents:
- Generic Thermal Layer (sysfs)
- Kernel APIs (TBD)
============
INTRODUCTION
============
@@ -47,7 +49,6 @@ scalability, and user experience. In many cases, clear advantage is
shown over taking the CPU offline or modulating the CPU clock.
===================
THEORY OF OPERATION
===================
@@ -57,11 +58,12 @@ Idle Injection
On modern Intel processors (Nehalem or later), package level C-state
residency is available in MSRs, thus also available to the kernel.
These MSRs are:
#define MSR_PKG_C2_RESIDENCY 0x60D
#define MSR_PKG_C3_RESIDENCY 0x3F8
#define MSR_PKG_C6_RESIDENCY 0x3F9
#define MSR_PKG_C7_RESIDENCY 0x3FA
These MSRs are::
#define MSR_PKG_C2_RESIDENCY 0x60D
#define MSR_PKG_C3_RESIDENCY 0x3F8
#define MSR_PKG_C6_RESIDENCY 0x3F9
#define MSR_PKG_C7_RESIDENCY 0x3FA
If the kernel can also inject idle time to the system, then a
closed-loop control system can be established that manages package
@@ -96,19 +98,21 @@ are not masked. Tests show that the extra wakeups from scheduler tick
have a dramatic impact on the effectiveness of the powerclamp driver
on large scale systems (Westmere system with 80 processors).
CPU0
____________ ____________
kidle_inject/0 | sleep | mwait | sleep |
_________| |________| |_______
duration
CPU1
____________ ____________
kidle_inject/1 | sleep | mwait | sleep |
_________| |________| |_______
^
|
|
roundup(jiffies, interval)
::
CPU0
____________ ____________
kidle_inject/0 | sleep | mwait | sleep |
_________| |________| |_______
duration
CPU1
____________ ____________
kidle_inject/1 | sleep | mwait | sleep |
_________| |________| |_______
^
|
|
roundup(jiffies, interval)
Only one CPU is allowed to collect statistics and update global
control parameters. This CPU is referred to as the controlling CPU in
@@ -148,7 +152,7 @@ b) determine the amount of compensation needed at each target ratio
Compensation to each target ratio consists of two parts:
a) steady state error compensation
a) steady state error compensation
This is to offset the error occurring when the system can
enter idle without extra wakeups (such as external interrupts).
@@ -158,41 +162,42 @@ Compensation to each target ratio consists of two parts:
slowing down CPU activities.
A debugfs file is provided for the user to examine compensation
progress and results, such as on a Westmere system.
[jacob@nex01 ~]$ cat
/sys/kernel/debug/intel_powerclamp/powerclamp_calib
controlling cpu: 0
pct confidence steady dynamic (compensation)
0 0 0 0
1 1 0 0
2 1 1 0
3 3 1 0
4 3 1 0
5 3 1 0
6 3 1 0
7 3 1 0
8 3 1 0
...
30 3 2 0
31 3 2 0
32 3 1 0
33 3 2 0
34 3 1 0
35 3 2 0
36 3 1 0
37 3 2 0
38 3 1 0
39 3 2 0
40 3 3 0
41 3 1 0
42 3 2 0
43 3 1 0
44 3 1 0
45 3 2 0
46 3 3 0
47 3 0 0
48 3 2 0
49 3 3 0
progress and results, such as on a Westmere system::
[jacob@nex01 ~]$ cat
/sys/kernel/debug/intel_powerclamp/powerclamp_calib
controlling cpu: 0
pct confidence steady dynamic (compensation)
0 0 0 0
1 1 0 0
2 1 1 0
3 3 1 0
4 3 1 0
5 3 1 0
6 3 1 0
7 3 1 0
8 3 1 0
...
30 3 2 0
31 3 2 0
32 3 1 0
33 3 2 0
34 3 1 0
35 3 2 0
36 3 1 0
37 3 2 0
38 3 1 0
39 3 2 0
40 3 3 0
41 3 1 0
42 3 2 0
43 3 1 0
44 3 1 0
45 3 2 0
46 3 3 0
47 3 0 0
48 3 2 0
49 3 3 0
Calibration occurs during runtime. No offline method is available.
Steady state compensation is used only when confidence levels of all
@@ -217,9 +222,8 @@ keeps track of clamping kernel threads, even after they are migrated
to other CPUs, after a CPU offline event.
=====================
Performance Analysis
=====================
====================
This section describes the general performance data collected on
multiple systems, including Westmere (80P) and Ivy Bridge (4P, 8P).
@@ -257,16 +261,15 @@ achieve up to 40% better performance per watt. (measured by a spin
counter summed over per CPU counting threads spawned for all running
CPUs).
====================
Usage and Interfaces
====================
The powerclamp driver is registered to the generic thermal layer as a
cooling device. Currently, it’s not bound to any thermal zones.
cooling device. Currently, it’s not bound to any thermal zones::
jacob@chromoly:/sys/class/thermal/cooling_device14$ grep . *
cur_state:0
max_state:50
type:intel_powerclamp
jacob@chromoly:/sys/class/thermal/cooling_device14$ grep . *
cur_state:0
max_state:50
type:intel_powerclamp
cur_state allows user to set the desired idle percentage. Writing 0 to
cur_state will stop idle injection. Writing a value between 1 and
@@ -278,9 +281,9 @@ cur_state returns value -1 instead of 0 which is to avoid confusing
100% busy state with the disabled state.
Example usage:
- To inject 25% idle time
$ sudo sh -c "echo 25 > /sys/class/thermal/cooling_device80/cur_state
"
- To inject 25% idle time::
$ sudo sh -c "echo 25 > /sys/class/thermal/cooling_device80/cur_state
If the system is not busy and has more than 25% idle time already,
then the powerclamp driver will not start idle injection. Using Top
@@ -292,23 +295,23 @@ idle time is accounted as normal idle in that common code path is
taken as the idle task.
In this example, 24.1% idle is shown. This helps the system admin or
user determine the cause of slowdown, when a powerclamp driver is in action.
user determine the cause of slowdown, when a powerclamp driver is in action::
Tasks: 197 total, 1 running, 196 sleeping, 0 stopped, 0 zombie
Cpu(s): 71.2%us, 4.7%sy, 0.0%ni, 24.1%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 3943228k total, 1689632k used, 2253596k free, 74960k buffers
Swap: 4087804k total, 0k used, 4087804k free, 945336k cached
Tasks: 197 total, 1 running, 196 sleeping, 0 stopped, 0 zombie
Cpu(s): 71.2%us, 4.7%sy, 0.0%ni, 24.1%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 3943228k total, 1689632k used, 2253596k free, 74960k buffers
Swap: 4087804k total, 0k used, 4087804k free, 945336k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
3352 jacob 20 0 262m 644 428 S 286 0.0 0:17.16 spin
3341 root -51 0 0 0 0 D 25 0.0 0:01.62 kidle_inject/0
3344 root -51 0 0 0 0 D 25 0.0 0:01.60 kidle_inject/3
3342 root -51 0 0 0 0 D 25 0.0 0:01.61 kidle_inject/1
3343 root -51 0 0 0 0 D 25 0.0 0:01.60 kidle_inject/2
2935 jacob 20 0 696m 125m 35m S 5 3.3 0:31.11 firefox
1546 root 20 0 158m 20m 6640 S 3 0.5 0:26.97 Xorg
2100 jacob 20 0 1223m 88m 30m S 3 2.3 0:23.68 compiz
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
3352 jacob 20 0 262m 644 428 S 286 0.0 0:17.16 spin
3341 root -51 0 0 0 0 D 25 0.0 0:01.62 kidle_inject/0
3344 root -51 0 0 0 0 D 25 0.0 0:01.60 kidle_inject/3
3342 root -51 0 0 0 0 D 25 0.0 0:01.61 kidle_inject/1
3343 root -51 0 0 0 0 D 25 0.0 0:01.60 kidle_inject/2
2935 jacob 20 0 696m 125m 35m S 5 3.3 0:31.11 firefox
1546 root 20 0 158m 20m 6640 S 3 0.5 0:26.97 Xorg
2100 jacob 20 0 1223m 88m 30m S 3 2.3 0:23.68 compiz
Tests have shown that by using the powerclamp driver as a cooling
device, a PID based userspace thermal controller can manage to
Documentation/thermal/nouveau_thermal → Documentation/thermal/nouveau_thermal.rst
+34 -20
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@@ -1,13 +1,15 @@
=====================
Kernel driver nouveau
===================
=====================
Supported chips:
* NV43+
Authors: Martin Peres (mupuf) <martin.peres@free.fr>
Description
---------
-----------
This driver allows to read the GPU core temperature, drive the GPU fan and
set temperature alarms.
@@ -19,20 +21,25 @@ interface is likely not to work. This document may then not cover your situation
entirely.
Temperature management
--------------------
----------------------
Temperature is exposed under as a read-only HWMON attribute temp1_input.
In order to protect the GPU from overheating, Nouveau supports 4 configurable
temperature thresholds:
* Fan_boost: Fan speed is set to 100% when reaching this temperature;
* Downclock: The GPU will be downclocked to reduce its power dissipation;
* Critical: The GPU is put on hold to further lower power dissipation;
* Shutdown: Shut the computer down to protect your GPU.
* Fan_boost:
Fan speed is set to 100% when reaching this temperature;
* Downclock:
The GPU will be downclocked to reduce its power dissipation;
* Critical:
The GPU is put on hold to further lower power dissipation;
* Shutdown:
Shut the computer down to protect your GPU.
WARNING: Some of these thresholds may not be used by Nouveau depending
on your chipset.
WARNING:
Some of these thresholds may not be used by Nouveau depending
on your chipset.
The default value for these thresholds comes from the GPU's vbios. These
thresholds can be configured thanks to the following HWMON attributes:
@@ -46,19 +53,24 @@ NOTE: Remember that the values are stored as milli degrees Celsius. Don't forget
to multiply!
Fan management
------------
--------------
Not all cards have a drivable fan. If you do, then the following HWMON
attributes should be available:
* pwm1_enable: Current fan management mode (NONE, MANUAL or AUTO);
* pwm1: Current PWM value (power percentage);
* pwm1_min: The minimum PWM speed allowed;
* pwm1_max: The maximum PWM speed allowed (bypassed when hitting Fan_boost);
* pwm1_enable:
Current fan management mode (NONE, MANUAL or AUTO);
* pwm1:
Current PWM value (power percentage);
* pwm1_min:
The minimum PWM speed allowed;
* pwm1_max:
The maximum PWM speed allowed (bypassed when hitting Fan_boost);
You may also have the following attribute:
* fan1_input: Speed in RPM of your fan.
* fan1_input:
Speed in RPM of your fan.
Your fan can be driven in different modes:
@@ -66,14 +78,16 @@ Your fan can be driven in different modes:
* 1: The fan can be driven in manual (use pwm1 to change the speed);
* 2; The fan is driven automatically depending on the temperature.
NOTE: Be sure to use the manual mode if you want to drive the fan speed manually
NOTE:
Be sure to use the manual mode if you want to drive the fan speed manually
NOTE2: When operating in manual mode outside the vbios-defined
[PWM_min, PWM_max] range, the reported fan speed (RPM) may not be accurate
depending on your hardware.
NOTE2:
When operating in manual mode outside the vbios-defined
[PWM_min, PWM_max] range, the reported fan speed (RPM) may not be accurate
depending on your hardware.
Bug reports
---------
-----------
Thermal management on Nouveau is new and may not work on all cards. If you have
inquiries, please ping mupuf on IRC (#nouveau, freenode).
Documentation/thermal/power_allocator.txt → Documentation/thermal/power_allocator.rst
+83 -59
View File
@@ -1,3 +1,4 @@
=================================
Power allocator governor tunables
=================================
@@ -25,36 +26,36 @@ temperature as the control input and power as the controlled output:
P_max = k_p * e + k_i * err_integral + k_d * diff_err + sustainable_power
where
e = desired_temperature - current_temperature
err_integral is the sum of previous errors
diff_err = e - previous_error
- e = desired_temperature - current_temperature
- err_integral is the sum of previous errors
- diff_err = e - previous_error
It is similar to the one depicted below:
It is similar to the one depicted below::
k_d
|
current_temp |
| v
| +----------+ +---+
| +----->| diff_err |-->| X |------+
| | +----------+ +---+ |
| | | tdp actor
| | k_i | | get_requested_power()
| | | | | | |
| | | | | | | ...
v | v v v v v
+---+ | +-------+ +---+ +---+ +---+ +----------+
| S |-------+----->| sum e |----->| X |--->| S |-->| S |-->|power |
+---+ | +-------+ +---+ +---+ +---+ |allocation|
^ | ^ +----------+
| | | | |
| | +---+ | | |
| +------->| X |-------------------+ v v
| +---+ granted performance
desired_temperature ^
|
|
k_po/k_pu
k_d
|
current_temp |
| v
| +----------+ +---+
| +----->| diff_err |-->| X |------+
| | +----------+ +---+ |
| | | tdp actor
| | k_i | | get_requested_power()
| | | | | | |
| | | | | | | ...
v | v v v v v
+---+ | +-------+ +---+ +---+ +---+ +----------+
| S |-----+----->| sum e |----->| X |--->| S |-->| S |-->|power |
+---+ | +-------+ +---+ +---+ +---+ |allocation|
^ | ^ +----------+
| | | | |
| | +---+ | | |
| +------->| X |-------------------+ v v
| +---+ granted performance
desired_temperature ^
|
|
k_po/k_pu
Sustainable power
-----------------
@@ -73,7 +74,7 @@ is typically 2000mW, while on a 10" tablet is around 4500mW (may vary
depending on screen size).
If you are using device tree, do add it as a property of the
thermal-zone. For example:
thermal-zone. For example::
thermal-zones {
soc_thermal {
@@ -85,7 +86,7 @@ thermal-zone. For example:
Instead, if the thermal zone is registered from the platform code, pass a
`thermal_zone_params` that has a `sustainable_power`. If no
`thermal_zone_params` were being passed, then something like below
will suffice:
will suffice::
static const struct thermal_zone_params tz_params = {
.sustainable_power = 3500,
@@ -112,18 +113,18 @@ available capacity at a low temperature. On the other hand, a high
value of `k_pu` will result in the governor granting very high power
while temperature is low, and may lead to temperature overshooting.
The default value for `k_pu` is:
The default value for `k_pu` is::
2 * sustainable_power / (desired_temperature - switch_on_temp)
This means that at `switch_on_temp` the output of the controller's
proportional term will be 2 * `sustainable_power`. The default value
for `k_po` is:
for `k_po` is::
sustainable_power / (desired_temperature - switch_on_temp)
Focusing on the proportional and feed forward values of the PID
controller equation we have:
controller equation we have::
P_max = k_p * e + sustainable_power
@@ -134,21 +135,23 @@ is the desired one, then the proportional component is zero and
thermal equilibrium under constant load. `sustainable_power` is only
an estimate, which is the reason for closed-loop control such as this.
Expanding `k_pu` we get:
P_max = 2 * sustainable_power * (T_set - T) / (T_set - T_on) +
sustainable_power
Expanding `k_pu` we get::
where
T_set is the desired temperature
T is the current temperature
T_on is the switch on temperature
P_max = 2 * sustainable_power * (T_set - T) / (T_set - T_on) +
sustainable_power
where:
- T_set is the desired temperature
- T is the current temperature
- T_on is the switch on temperature
When the current temperature is the switch_on temperature, the above
formula becomes:
formula becomes::
P_max = 2 * sustainable_power * (T_set - T_on) / (T_set - T_on) +
sustainable_power = 2 * sustainable_power + sustainable_power =
3 * sustainable_power
sustainable_power = 2 * sustainable_power + sustainable_power =
3 * sustainable_power
Therefore, the proportional term alone linearly decreases power from
3 * `sustainable_power` to `sustainable_power` as the temperature
@@ -178,11 +181,18 @@ Cooling device power API
Cooling devices controlled by this governor must supply the additional
"power" API in their `cooling_device_ops`. It consists on three ops:
1. int get_requested_power(struct thermal_cooling_device *cdev,
struct thermal_zone_device *tz, u32 *power);
@cdev: The `struct thermal_cooling_device` pointer
@tz: thermal zone in which we are currently operating
@power: pointer in which to store the calculated power
1. ::
int get_requested_power(struct thermal_cooling_device *cdev,
struct thermal_zone_device *tz, u32 *power);
@cdev:
The `struct thermal_cooling_device` pointer
@tz:
thermal zone in which we are currently operating
@power:
pointer in which to store the calculated power
`get_requested_power()` calculates the power requested by the device
in milliwatts and stores it in @power . It should return 0 on
@@ -190,23 +200,37 @@ success, -E* on failure. This is currently used by the power
allocator governor to calculate how much power to give to each cooling
device.
2. int state2power(struct thermal_cooling_device *cdev, struct
thermal_zone_device *tz, unsigned long state, u32 *power);
@cdev: The `struct thermal_cooling_device` pointer
@tz: thermal zone in which we are currently operating
@state: A cooling device state
@power: pointer in which to store the equivalent power
2. ::
int state2power(struct thermal_cooling_device *cdev, struct
thermal_zone_device *tz, unsigned long state,
u32 *power);
@cdev:
The `struct thermal_cooling_device` pointer
@tz:
thermal zone in which we are currently operating
@state:
A cooling device state
@power:
pointer in which to store the equivalent power
Convert cooling device state @state into power consumption in
milliwatts and store it in @power. It should return 0 on success, -E*
on failure. This is currently used by thermal core to calculate the
maximum power that an actor can consume.
3. int power2state(struct thermal_cooling_device *cdev, u32 power,
unsigned long *state);
@cdev: The `struct thermal_cooling_device` pointer
@power: power in milliwatts
@state: pointer in which to store the resulting state
3. ::
int power2state(struct thermal_cooling_device *cdev, u32 power,
unsigned long *state);
@cdev:
The `struct thermal_cooling_device` pointer
@power:
power in milliwatts
@state:
pointer in which to store the resulting state
Calculate a cooling device state that would make the device consume at
most @power mW and store it in @state. It should return 0 on success,
Documentation/thermal/sysfs-api.txt → Documentation/thermal/sysfs-api.rst
+331 -169
View File
File diff suppressed because it is too large Load Diff
Documentation/thermal/x86_pkg_temperature_thermal → Documentation/thermal/x86_pkg_temperature_thermal.rst
+18 -10
View File
@@ -1,19 +1,23 @@
===================================
Kernel driver: x86_pkg_temp_thermal
===================
===================================
Supported chips:
* x86: with package level thermal management
(Verify using: CPUID.06H:EAX[bit 6] =1)
Authors: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Reference
---
---------
Intel® 64 and IA-32 Architectures Software Developer’s Manual (Jan, 2013):
Chapter 14.6: PACKAGE LEVEL THERMAL MANAGEMENT
Description
---------
-----------
This driver register CPU digital temperature package level sensor as a thermal
zone with maximum two user mode configurable trip points. Number of trip points
@@ -25,23 +29,27 @@ take any action to control temperature.
Threshold management
--------------------
Each package will register as a thermal zone under /sys/class/thermal.
Example:
/sys/class/thermal/thermal_zone1
Example::
/sys/class/thermal/thermal_zone1
This contains two trip points:
- trip_point_0_temp
- trip_point_1_temp
User can set any temperature between 0 to TJ-Max temperature. Temperature units
are in milli-degree Celsius. Refer to "Documentation/thermal/sysfs-api.txt" for
are in milli-degree Celsius. Refer to "Documentation/thermal/sysfs-api.rst" for
thermal sys-fs details.
Any value other than 0 in these trip points, can trigger thermal notifications.
Setting 0, stops sending thermal notifications.
Thermal notifications: To get kobject-uevent notifications, set the thermal zone
policy to "user_space". For example: echo -n "user_space" > policy
Thermal notifications:
To get kobject-uevent notifications, set the thermal zone
policy to "user_space".
For example::
echo -n "user_space" > policy
MAINTAINERS
+1 -1
View File
@@ -15618,7 +15618,7 @@ M: Viresh Kumar <viresh.kumar@linaro.org>
M: Javi Merino <javi.merino@kernel.org>
L: linux-pm@vger.kernel.org
S: Supported
F: Documentation/thermal/cpu-cooling-api.txt
F: Documentation/thermal/cpu-cooling-api.rst
F: drivers/thermal/cpu_cooling.c
F: include/linux/cpu_cooling.h
include/linux/thermal.h
+2 -2
View File
@@ -251,7 +251,7 @@ struct thermal_bind_params {
* platform characterization. This value is relative to the
* rest of the weights so a cooling device whose weight is
* double that of another cooling device is twice as
* effective. See Documentation/thermal/sysfs-api.txt for more
* effective. See Documentation/thermal/sysfs-api.rst for more
* information.
*/
int weight;
@@ -259,7 +259,7 @@ struct thermal_bind_params {
/*
* This is a bit mask that gives the binding relation between this
* thermal zone and cdev, for a particular trip point.
* See Documentation/thermal/sysfs-api.txt for more information.
* See Documentation/thermal/sysfs-api.rst for more information.
*/
int trip_mask;