1# SPDX-License-Identifier: GPL-2.0-only 2menu "CPU Frequency scaling" 3 4config CPU_FREQ 5 bool "CPU Frequency scaling" 6 help 7 CPU Frequency scaling allows you to change the clock speed of 8 CPUs on the fly. This is a nice method to save power, because 9 the lower the CPU clock speed, the less power the CPU consumes. 10 11 Note that this driver doesn't automatically change the CPU 12 clock speed, you need to either enable a dynamic cpufreq governor 13 (see below) after boot, or use a userspace tool. 14 15 For details, take a look at 16 <file:Documentation/admin-guide/pm/cpufreq.rst>. 17 18 If in doubt, say N. 19 20if CPU_FREQ 21 22config CPU_FREQ_GOV_ATTR_SET 23 bool 24 25config CPU_FREQ_GOV_COMMON 26 select CPU_FREQ_GOV_ATTR_SET 27 select IRQ_WORK 28 bool 29 30config CPU_FREQ_STAT 31 bool "CPU frequency transition statistics" 32 help 33 Export CPU frequency statistics information through sysfs. 34 35 If in doubt, say N. 36 37choice 38 prompt "Default CPUFreq governor" 39 default CPU_FREQ_DEFAULT_GOV_USERSPACE if ARM_SA1110_CPUFREQ 40 default CPU_FREQ_DEFAULT_GOV_SCHEDUTIL if ARM64 || ARM 41 default CPU_FREQ_DEFAULT_GOV_SCHEDUTIL if (X86_INTEL_PSTATE || X86_AMD_PSTATE) && SMP 42 default CPU_FREQ_DEFAULT_GOV_PERFORMANCE 43 help 44 This option sets which CPUFreq governor shall be loaded at 45 startup. If in doubt, use the default setting. 46 47config CPU_FREQ_DEFAULT_GOV_PERFORMANCE 48 bool "performance" 49 select CPU_FREQ_GOV_PERFORMANCE 50 help 51 Use the CPUFreq governor 'performance' as default. This sets 52 the frequency statically to the highest frequency supported by 53 the CPU. 54 55config CPU_FREQ_DEFAULT_GOV_POWERSAVE 56 bool "powersave" 57 select CPU_FREQ_GOV_POWERSAVE 58 help 59 Use the CPUFreq governor 'powersave' as default. This sets 60 the frequency statically to the lowest frequency supported by 61 the CPU. 62 63config CPU_FREQ_DEFAULT_GOV_USERSPACE 64 bool "userspace" 65 select CPU_FREQ_GOV_USERSPACE 66 help 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. 71 72config CPU_FREQ_DEFAULT_GOV_ONDEMAND 73 bool "ondemand" 74 depends on !(X86_INTEL_PSTATE && SMP) 75 select CPU_FREQ_GOV_ONDEMAND 76 select CPU_FREQ_GOV_PERFORMANCE 77 help 78 Use the CPUFreq governor 'ondemand' as default. This allows 79 you to get a full dynamic frequency capable system by simply 80 loading your cpufreq low-level hardware driver. 81 Be aware that not all cpufreq drivers support the ondemand 82 governor. If unsure have a look at the help section of the 83 driver. Fallback governor will be the performance governor. 84 85config CPU_FREQ_DEFAULT_GOV_CONSERVATIVE 86 bool "conservative" 87 depends on !(X86_INTEL_PSTATE && SMP) 88 select CPU_FREQ_GOV_CONSERVATIVE 89 select CPU_FREQ_GOV_PERFORMANCE 90 help 91 Use the CPUFreq governor 'conservative' as default. This allows 92 you to get a full dynamic frequency capable system by simply 93 loading your cpufreq low-level hardware driver. 94 Be aware that not all cpufreq drivers support the conservative 95 governor. If unsure have a look at the help section of the 96 driver. Fallback governor will be the performance governor. 97 98config CPU_FREQ_DEFAULT_GOV_SCHEDUTIL 99 bool "schedutil" 100 depends on SMP 101 select CPU_FREQ_GOV_SCHEDUTIL 102 select CPU_FREQ_GOV_PERFORMANCE 103 help 104 Use the 'schedutil' CPUFreq governor by default. If unsure, 105 have a look at the help section of that governor. The fallback 106 governor will be 'performance'. 107 108endchoice 109 110config CPU_FREQ_GOV_PERFORMANCE 111 tristate "'performance' governor" 112 help 113 This cpufreq governor sets the frequency statically to the 114 highest available CPU frequency. 115 116 To compile this driver as a module, choose M here: the 117 module will be called cpufreq_performance. 118 119 If in doubt, say Y. 120 121config CPU_FREQ_GOV_POWERSAVE 122 tristate "'powersave' governor" 123 help 124 This cpufreq governor sets the frequency statically to the 125 lowest available CPU frequency. 126 127 To compile this driver as a module, choose M here: the 128 module will be called cpufreq_powersave. 129 130 If in doubt, say Y. 131 132config CPU_FREQ_GOV_USERSPACE 133 tristate "'userspace' governor for userspace frequency scaling" 134 help 135 Enable this cpufreq governor when you either want to set the 136 CPU frequency manually or when a userspace program shall 137 be able to set the CPU dynamically, like on LART 138 <http://www.lartmaker.nl/>. 139 140 To compile this driver as a module, choose M here: the 141 module will be called cpufreq_userspace. 142 143 If in doubt, say Y. 144 145config CPU_FREQ_GOV_ONDEMAND 146 tristate "'ondemand' cpufreq policy governor" 147 select CPU_FREQ_GOV_COMMON 148 help 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 154 transitions). 155 156 To compile this driver as a module, choose M here: the 157 module will be called cpufreq_ondemand. 158 159 For details, take a look at 160 <file:Documentation/admin-guide/pm/cpufreq.rst>. 161 162 If in doubt, say N. 163 164config CPU_FREQ_GOV_CONSERVATIVE 165 tristate "'conservative' cpufreq governor" 166 depends on CPU_FREQ 167 select CPU_FREQ_GOV_COMMON 168 help 169 'conservative' - this driver is rather similar to the 'ondemand' 170 governor both in its source code and its purpose, the difference is 171 its optimisation for better suitability in a battery powered 172 environment. The frequency is gracefully increased and decreased 173 rather than jumping to 100% when speed is required. 174 175 If you have a desktop machine then you should really be considering 176 the 'ondemand' governor instead, however if you are using a laptop, 177 PDA or even an AMD64 based computer (due to the unacceptable 178 step-by-step latency issues between the minimum and maximum frequency 179 transitions in the CPU) you will probably want to use this governor. 180 181 To compile this driver as a module, choose M here: the 182 module will be called cpufreq_conservative. 183 184 For details, take a look at 185 <file:Documentation/admin-guide/pm/cpufreq.rst>. 186 187 If in doubt, say N. 188 189config CPU_FREQ_GOV_SCHEDUTIL 190 bool "'schedutil' cpufreq policy governor" 191 depends on CPU_FREQ && SMP 192 select CPU_FREQ_GOV_ATTR_SET 193 select IRQ_WORK 194 help 195 This governor makes decisions based on the utilization data provided 196 by the scheduler. It sets the CPU frequency to be proportional to 197 the utilization/capacity ratio coming from the scheduler. If the 198 utilization is frequency-invariant, the new frequency is also 199 proportional to the maximum available frequency. If that is not the 200 case, it is proportional to the current frequency of the CPU. The 201 frequency tipping point is at utilization/capacity equal to 80% in 202 both cases. 203 204 If in doubt, say N. 205 206comment "CPU frequency scaling drivers" 207 208config CPUFREQ_DT 209 tristate "Generic DT based cpufreq driver" 210 depends on HAVE_CLK && OF 211 select CPUFREQ_DT_PLATDEV 212 select PM_OPP 213 help 214 This adds a generic DT based cpufreq driver for frequency management. 215 It supports both uniprocessor (UP) and symmetric multiprocessor (SMP) 216 systems. 217 218 If in doubt, say N. 219 220config CPUFREQ_VIRT 221 tristate "Virtual cpufreq driver" 222 depends on GENERIC_ARCH_TOPOLOGY 223 help 224 This adds a virtualized cpufreq driver for guest kernels that 225 read/writes to a MMIO region for a virtualized cpufreq device to 226 communicate with the host. It sends performance requests to the host 227 which gets used as a hint to schedule vCPU threads and select CPU 228 frequency. If a VM does not support a virtualized FIE such as AMUs, 229 it updates the frequency scaling factor by polling host CPU frequency 230 to enable accurate Per-Entity Load Tracking for tasks running in the guest. 231 232 If in doubt, say N. 233 234config CPUFREQ_DT_PLATDEV 235 tristate "Generic DT based cpufreq platdev driver" 236 depends on OF 237 help 238 This adds a generic DT based cpufreq platdev driver for frequency 239 management. This creates a 'cpufreq-dt' platform device, on the 240 supported platforms. 241 242 If in doubt, say N. 243 244if X86 245source "drivers/cpufreq/Kconfig.x86" 246endif 247 248source "drivers/cpufreq/Kconfig.arm" 249 250if PPC32 || PPC64 251source "drivers/cpufreq/Kconfig.powerpc" 252endif 253 254if MIPS 255config BMIPS_CPUFREQ 256 tristate "BMIPS CPUfreq Driver" 257 help 258 This option adds a CPUfreq driver for BMIPS processors with 259 support for configurable CPU frequency. 260 261 For now, BMIPS5 chips are supported (such as the Broadcom 7425). 262 263 If in doubt, say N. 264 265config LOONGSON2_CPUFREQ 266 tristate "Loongson2 CPUFreq Driver" 267 depends on LEMOTE_MACH2F 268 help 269 This option adds a CPUFreq driver for loongson processors which 270 support software configurable cpu frequency. 271 272 Loongson2F and its successors support this feature. 273 274 If in doubt, say N. 275endif 276 277if LOONGARCH 278config LOONGSON3_CPUFREQ 279 tristate "Loongson3 CPUFreq Driver" 280 help 281 This option adds a CPUFreq driver for Loongson processors which 282 support software configurable cpu frequency. 283 284 Loongson-3 family processors support this feature. 285 286 If in doubt, say N. 287endif 288 289if SPARC64 290config SPARC_US3_CPUFREQ 291 tristate "UltraSPARC-III CPU Frequency driver" 292 help 293 This adds the CPUFreq driver for UltraSPARC-III processors. 294 295 If in doubt, say N. 296 297config SPARC_US2E_CPUFREQ 298 tristate "UltraSPARC-IIe CPU Frequency driver" 299 help 300 This adds the CPUFreq driver for UltraSPARC-IIe processors. 301 302 If in doubt, say N. 303endif 304 305if SUPERH 306config SH_CPU_FREQ 307 tristate "SuperH CPU Frequency driver" 308 help 309 This adds the cpufreq driver for SuperH. Any CPU that supports 310 clock rate rounding through the clock framework can use this 311 driver. While it will make the kernel slightly larger, this is 312 harmless for CPUs that don't support rate rounding. The driver 313 will also generate a notice in the boot log before disabling 314 itself if the CPU in question is not capable of rate rounding. 315 316 If unsure, say N. 317endif 318 319config QORIQ_CPUFREQ 320 tristate "CPU frequency scaling driver for Freescale QorIQ SoCs" 321 depends on OF && COMMON_CLK 322 depends on PPC_E500MC || SOC_LS1021A || ARCH_LAYERSCAPE || COMPILE_TEST 323 select CLK_QORIQ 324 help 325 This adds the CPUFreq driver support for Freescale QorIQ SoCs 326 which are capable of changing the CPU's frequency dynamically. 327 328endif 329 330config ACPI_CPPC_CPUFREQ 331 tristate "CPUFreq driver based on the ACPI CPPC spec" 332 depends on ACPI_PROCESSOR 333 depends on ARM || ARM64 || RISCV 334 select ACPI_CPPC_LIB 335 help 336 This adds a CPUFreq driver which uses CPPC methods 337 as described in the ACPIv5.1 spec. CPPC stands for 338 Collaborative Processor Performance Controls. It 339 is based on an abstract continuous scale of CPU 340 performance values which allows the remote power 341 processor to flexibly optimize for power and 342 performance. CPPC relies on power management firmware 343 support for its operation. 344 345 If in doubt, say N. 346 347config ACPI_CPPC_CPUFREQ_FIE 348 bool "Frequency Invariance support for CPPC cpufreq driver" 349 depends on ACPI_CPPC_CPUFREQ && GENERIC_ARCH_TOPOLOGY 350 depends on ARM || ARM64 || RISCV 351 default y 352 help 353 This extends frequency invariance support in the CPPC cpufreq driver, 354 by using CPPC delivered and reference performance counters. 355 356 If in doubt, say N. 357 358endmenu 359