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_DT_RUST 221 tristate "Rust based Generic DT based cpufreq driver" 222 depends on HAVE_CLK && OF && RUST 223 select CPUFREQ_DT_PLATDEV 224 select PM_OPP 225 help 226 This adds a Rust based generic DT based cpufreq driver for frequency 227 management. It supports both uniprocessor (UP) and symmetric 228 multiprocessor (SMP) systems. 229 230 If in doubt, say N. 231 232config CPUFREQ_VIRT 233 tristate "Virtual cpufreq driver" 234 depends on GENERIC_ARCH_TOPOLOGY 235 help 236 This adds a virtualized cpufreq driver for guest kernels that 237 read/writes to a MMIO region for a virtualized cpufreq device to 238 communicate with the host. It sends performance requests to the host 239 which gets used as a hint to schedule vCPU threads and select CPU 240 frequency. If a VM does not support a virtualized FIE such as AMUs, 241 it updates the frequency scaling factor by polling host CPU frequency 242 to enable accurate Per-Entity Load Tracking for tasks running in the guest. 243 244 If in doubt, say N. 245 246config CPUFREQ_DT_PLATDEV 247 bool "Generic DT based cpufreq platdev driver" 248 depends on OF 249 help 250 This adds a generic DT based cpufreq platdev driver for frequency 251 management. This creates a 'cpufreq-dt' platform device, on the 252 supported platforms. 253 254 If in doubt, say N. 255 256if X86 257source "drivers/cpufreq/Kconfig.x86" 258endif 259 260source "drivers/cpufreq/Kconfig.arm" 261 262if PPC32 || PPC64 263source "drivers/cpufreq/Kconfig.powerpc" 264endif 265 266if MIPS 267config BMIPS_CPUFREQ 268 tristate "BMIPS CPUfreq Driver" 269 help 270 This option adds a CPUfreq driver for BMIPS processors with 271 support for configurable CPU frequency. 272 273 For now, BMIPS5 chips are supported (such as the Broadcom 7425). 274 275 If in doubt, say N. 276 277config LOONGSON2_CPUFREQ 278 tristate "Loongson2 CPUFreq Driver" 279 depends on LEMOTE_MACH2F 280 help 281 This option adds a CPUFreq driver for loongson processors which 282 support software configurable cpu frequency. 283 284 Loongson2F and its successors support this feature. 285 286 If in doubt, say N. 287endif 288 289if LOONGARCH 290config LOONGSON3_CPUFREQ 291 tristate "Loongson3 CPUFreq Driver" 292 help 293 This option adds a CPUFreq driver for Loongson processors which 294 support software configurable cpu frequency. 295 296 Loongson-3 family processors support this feature. 297 298 If in doubt, say N. 299endif 300 301if SPARC64 302config SPARC_US3_CPUFREQ 303 tristate "UltraSPARC-III CPU Frequency driver" 304 help 305 This adds the CPUFreq driver for UltraSPARC-III processors. 306 307 If in doubt, say N. 308 309config SPARC_US2E_CPUFREQ 310 tristate "UltraSPARC-IIe CPU Frequency driver" 311 help 312 This adds the CPUFreq driver for UltraSPARC-IIe processors. 313 314 If in doubt, say N. 315endif 316 317if SUPERH 318config SH_CPU_FREQ 319 tristate "SuperH CPU Frequency driver" 320 help 321 This adds the cpufreq driver for SuperH. Any CPU that supports 322 clock rate rounding through the clock framework can use this 323 driver. While it will make the kernel slightly larger, this is 324 harmless for CPUs that don't support rate rounding. The driver 325 will also generate a notice in the boot log before disabling 326 itself if the CPU in question is not capable of rate rounding. 327 328 If unsure, say N. 329endif 330 331config QORIQ_CPUFREQ 332 tristate "CPU frequency scaling driver for Freescale QorIQ SoCs" 333 depends on OF && COMMON_CLK 334 depends on PPC_E500MC || SOC_LS1021A || ARCH_LAYERSCAPE || COMPILE_TEST 335 select CLK_QORIQ 336 help 337 This adds the CPUFreq driver support for Freescale QorIQ SoCs 338 which are capable of changing the CPU's frequency dynamically. 339 340config ACPI_CPPC_CPUFREQ 341 tristate "CPUFreq driver based on the ACPI CPPC spec" 342 depends on ACPI_PROCESSOR 343 depends on ARM || ARM64 || RISCV 344 select ACPI_CPPC_LIB 345 help 346 This adds a CPUFreq driver which uses CPPC methods 347 as described in the ACPIv5.1 spec. CPPC stands for 348 Collaborative Processor Performance Controls. It 349 is based on an abstract continuous scale of CPU 350 performance values which allows the remote power 351 processor to flexibly optimize for power and 352 performance. CPPC relies on power management firmware 353 support for its operation. 354 355 If in doubt, say N. 356 357config ACPI_CPPC_CPUFREQ_FIE 358 bool "Frequency Invariance support for CPPC cpufreq driver" 359 depends on ACPI_CPPC_CPUFREQ && GENERIC_ARCH_TOPOLOGY 360 depends on ARM || ARM64 || RISCV 361 default y 362 help 363 This extends frequency invariance support in the CPPC cpufreq driver, 364 by using CPPC delivered and reference performance counters. 365 366 If in doubt, say N. 367 368endif 369 370endmenu 371