1 # SPDX-License-Identifier: GPL-2.0-only
2 menu "CPU Frequency scaling"
5 bool "CPU Frequency scaling"
8 CPU Frequency scaling allows you to change the clock speed of
9 CPUs on the fly. This is a nice method to save power, because
10 the lower the CPU clock speed, the less power the CPU consumes.
12 Note that this driver doesn't automatically change the CPU
13 clock speed, you need to either enable a dynamic cpufreq governor
14 (see below) after boot, or use a userspace tool.
16 For details, take a look at <file:Documentation/cpu-freq>.
22 config CPU_FREQ_GOV_ATTR_SET
25 config CPU_FREQ_GOV_COMMON
26 select CPU_FREQ_GOV_ATTR_SET
31 bool "CPU frequency transition statistics"
33 Export CPU frequency statistics information through sysfs.
38 prompt "Default CPUFreq governor"
39 default CPU_FREQ_DEFAULT_GOV_USERSPACE if ARM_SA1100_CPUFREQ || ARM_SA1110_CPUFREQ
40 default CPU_FREQ_DEFAULT_GOV_SCHEDUTIL if ARM64 || ARM
41 default CPU_FREQ_DEFAULT_GOV_SCHEDUTIL if X86_INTEL_PSTATE && SMP
42 default CPU_FREQ_DEFAULT_GOV_PERFORMANCE
44 This option sets which CPUFreq governor shall be loaded at
45 startup. If in doubt, use the default setting.
47 config CPU_FREQ_DEFAULT_GOV_PERFORMANCE
49 select CPU_FREQ_GOV_PERFORMANCE
51 Use the CPUFreq governor 'performance' as default. This sets
52 the frequency statically to the highest frequency supported by
55 config CPU_FREQ_DEFAULT_GOV_POWERSAVE
57 select CPU_FREQ_GOV_POWERSAVE
59 Use the CPUFreq governor 'powersave' as default. This sets
60 the frequency statically to the lowest frequency supported by
63 config CPU_FREQ_DEFAULT_GOV_USERSPACE
65 select CPU_FREQ_GOV_USERSPACE
67 Use the CPUFreq governor 'userspace' as default. This allows
68 you to set the CPU frequency manually or when a userspace
69 program shall be able to set the CPU dynamically without having
70 to enable the userspace governor manually.
72 config CPU_FREQ_DEFAULT_GOV_ONDEMAND
74 select CPU_FREQ_GOV_ONDEMAND
75 select CPU_FREQ_GOV_PERFORMANCE
77 Use the CPUFreq governor 'ondemand' as default. This allows
78 you to get a full dynamic frequency capable system by simply
79 loading your cpufreq low-level hardware driver.
80 Be aware that not all cpufreq drivers support the ondemand
81 governor. If unsure have a look at the help section of the
82 driver. Fallback governor will be the performance governor.
84 config CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
86 select CPU_FREQ_GOV_CONSERVATIVE
87 select CPU_FREQ_GOV_PERFORMANCE
89 Use the CPUFreq governor 'conservative' as default. This allows
90 you to get a full dynamic frequency capable system by simply
91 loading your cpufreq low-level hardware driver.
92 Be aware that not all cpufreq drivers support the conservative
93 governor. If unsure have a look at the help section of the
94 driver. Fallback governor will be the performance governor.
96 config CPU_FREQ_DEFAULT_GOV_SCHEDUTIL
99 select CPU_FREQ_GOV_SCHEDUTIL
100 select CPU_FREQ_GOV_PERFORMANCE
102 Use the 'schedutil' CPUFreq governor by default. If unsure,
103 have a look at the help section of that governor. The fallback
104 governor will be 'performance'.
108 config CPU_FREQ_GOV_PERFORMANCE
109 tristate "'performance' governor"
111 This cpufreq governor sets the frequency statically to the
112 highest available CPU frequency.
114 To compile this driver as a module, choose M here: the
115 module will be called cpufreq_performance.
119 config CPU_FREQ_GOV_POWERSAVE
120 tristate "'powersave' governor"
122 This cpufreq governor sets the frequency statically to the
123 lowest available CPU frequency.
125 To compile this driver as a module, choose M here: the
126 module will be called cpufreq_powersave.
130 config CPU_FREQ_GOV_USERSPACE
131 tristate "'userspace' governor for userspace frequency scaling"
133 Enable this cpufreq governor when you either want to set the
134 CPU frequency manually or when a userspace program shall
135 be able to set the CPU dynamically, like on LART
136 <http://www.lartmaker.nl/>.
138 To compile this driver as a module, choose M here: the
139 module will be called cpufreq_userspace.
141 For details, take a look at <file:Documentation/cpu-freq/>.
145 config CPU_FREQ_GOV_ONDEMAND
146 tristate "'ondemand' cpufreq policy governor"
147 select CPU_FREQ_GOV_COMMON
149 'ondemand' - This driver adds a dynamic cpufreq policy governor.
150 The governor does a periodic polling and
151 changes frequency based on the CPU utilization.
152 The support for this governor depends on CPU capability to
153 do fast frequency switching (i.e, very low latency frequency
156 To compile this driver as a module, choose M here: the
157 module will be called cpufreq_ondemand.
159 For details, take a look at linux/Documentation/cpu-freq.
163 config CPU_FREQ_GOV_CONSERVATIVE
164 tristate "'conservative' cpufreq governor"
166 select CPU_FREQ_GOV_COMMON
168 'conservative' - this driver is rather similar to the 'ondemand'
169 governor both in its source code and its purpose, the difference is
170 its optimisation for better suitability in a battery powered
171 environment. The frequency is gracefully increased and decreased
172 rather than jumping to 100% when speed is required.
174 If you have a desktop machine then you should really be considering
175 the 'ondemand' governor instead, however if you are using a laptop,
176 PDA or even an AMD64 based computer (due to the unacceptable
177 step-by-step latency issues between the minimum and maximum frequency
178 transitions in the CPU) you will probably want to use this governor.
180 To compile this driver as a module, choose M here: the
181 module will be called cpufreq_conservative.
183 For details, take a look at linux/Documentation/cpu-freq.
187 config CPU_FREQ_GOV_SCHEDUTIL
188 bool "'schedutil' cpufreq policy governor"
189 depends on CPU_FREQ && SMP
190 select CPU_FREQ_GOV_ATTR_SET
193 This governor makes decisions based on the utilization data provided
194 by the scheduler. It sets the CPU frequency to be proportional to
195 the utilization/capacity ratio coming from the scheduler. If the
196 utilization is frequency-invariant, the new frequency is also
197 proportional to the maximum available frequency. If that is not the
198 case, it is proportional to the current frequency of the CPU. The
199 frequency tipping point is at utilization/capacity equal to 80% in
204 comment "CPU frequency scaling drivers"
207 tristate "Generic DT based cpufreq driver"
208 depends on HAVE_CLK && OF
209 select CPUFREQ_DT_PLATDEV
212 This adds a generic DT based cpufreq driver for frequency management.
213 It supports both uniprocessor (UP) and symmetric multiprocessor (SMP)
218 config CPUFREQ_DT_PLATDEV
221 This adds a generic DT based cpufreq platdev driver for frequency
222 management. This creates a 'cpufreq-dt' platform device, on the
228 source "drivers/cpufreq/Kconfig.x86"
232 source "drivers/cpufreq/Kconfig.arm"
236 source "drivers/cpufreq/Kconfig.powerpc"
240 config IA64_ACPI_CPUFREQ
241 tristate "ACPI Processor P-States driver"
242 depends on ACPI_PROCESSOR
244 This driver adds a CPUFreq driver which utilizes the ACPI
245 Processor Performance States.
247 For details, take a look at <file:Documentation/cpu-freq/>.
254 tristate "BMIPS CPUfreq Driver"
256 This option adds a CPUfreq driver for BMIPS processors with
257 support for configurable CPU frequency.
259 For now, BMIPS5 chips are supported (such as the Broadcom 7425).
263 config LOONGSON2_CPUFREQ
264 tristate "Loongson2 CPUFreq Driver"
265 depends on LEMOTE_MACH2F
267 This option adds a CPUFreq driver for loongson processors which
268 support software configurable cpu frequency.
270 Loongson2F and it's successors support this feature.
272 For details, take a look at <file:Documentation/cpu-freq/>.
276 config LOONGSON1_CPUFREQ
277 tristate "Loongson1 CPUFreq Driver"
278 depends on LOONGSON1_LS1B
280 This option adds a CPUFreq driver for loongson1 processors which
281 support software configurable cpu frequency.
283 For details, take a look at <file:Documentation/cpu-freq/>.
289 config SPARC_US3_CPUFREQ
290 tristate "UltraSPARC-III CPU Frequency driver"
292 This adds the CPUFreq driver for UltraSPARC-III processors.
294 For details, take a look at <file:Documentation/cpu-freq>.
298 config SPARC_US2E_CPUFREQ
299 tristate "UltraSPARC-IIe CPU Frequency driver"
301 This adds the CPUFreq driver for UltraSPARC-IIe processors.
303 For details, take a look at <file:Documentation/cpu-freq>.
310 tristate "SuperH CPU Frequency driver"
312 This adds the cpufreq driver for SuperH. Any CPU that supports
313 clock rate rounding through the clock framework can use this
314 driver. While it will make the kernel slightly larger, this is
315 harmless for CPUs that don't support rate rounding. The driver
316 will also generate a notice in the boot log before disabling
317 itself if the CPU in question is not capable of rate rounding.
319 For details, take a look at <file:Documentation/cpu-freq>.
325 tristate "CPU frequency scaling driver for Freescale QorIQ SoCs"
326 depends on OF && COMMON_CLK
327 depends on PPC_E500MC || SOC_LS1021A || ARCH_LAYERSCAPE || COMPILE_TEST
330 This adds the CPUFreq driver support for Freescale QorIQ SoCs
331 which are capable of changing the CPU's frequency dynamically.