Linux/kernel/time/Kconfig

Version: ~ [ linux-6.12-rc7 ] ~ [ linux-6.11.7 ] ~ [ linux-6.10.14 ] ~ [ linux-6.9.12 ] ~ [ linux-6.8.12 ] ~ [ linux-6.7.12 ] ~ [ linux-6.6.60 ] ~ [ linux-6.5.13 ] ~ [ linux-6.4.16 ] ~ [ linux-6.3.13 ] ~ [ linux-6.2.16 ] ~ [ linux-6.1.116 ] ~ [ linux-6.0.19 ] ~ [ linux-5.19.17 ] ~ [ linux-5.18.19 ] ~ [ linux-5.17.15 ] ~ [ linux-5.16.20 ] ~ [ linux-5.15.171 ] ~ [ linux-5.14.21 ] ~ [ linux-5.13.19 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.229 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.285 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.323 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.336 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.337 ] ~ [ linux-4.4.302 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.12 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

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1 # SPDX-License-Identifier: GPL-2.0-only << 2 # 1 # 3 # Timer subsystem related configuration option 2 # Timer subsystem related configuration options 4 # 3 # 5 4 6 # Options selectable by arch Kconfig 5 # Options selectable by arch Kconfig 7 6 8 # Watchdog function for clocksources to detect 7 # Watchdog function for clocksources to detect instabilities 9 config CLOCKSOURCE_WATCHDOG 8 config CLOCKSOURCE_WATCHDOG 10 bool 9 bool 11 10 12 # Architecture has extra clocksource data 11 # Architecture has extra clocksource data 13 config ARCH_CLOCKSOURCE_DATA 12 config ARCH_CLOCKSOURCE_DATA 14 bool 13 bool 15 14 16 # Architecture has extra clocksource init call << 17 config ARCH_CLOCKSOURCE_INIT << 18 bool << 19 << 20 # Clocksources require validation of the clock 15 # Clocksources require validation of the clocksource against the last 21 # cycle update - x86/TSC misfeature 16 # cycle update - x86/TSC misfeature 22 config CLOCKSOURCE_VALIDATE_LAST_CYCLE 17 config CLOCKSOURCE_VALIDATE_LAST_CYCLE 23 bool 18 bool 24 19 25 # Timekeeping vsyscall support 20 # Timekeeping vsyscall support 26 config GENERIC_TIME_VSYSCALL 21 config GENERIC_TIME_VSYSCALL 27 bool 22 bool 28 23 >> 24 # Old style timekeeping >> 25 config ARCH_USES_GETTIMEOFFSET >> 26 bool >> 27 29 # The generic clock events infrastructure 28 # The generic clock events infrastructure 30 config GENERIC_CLOCKEVENTS 29 config GENERIC_CLOCKEVENTS 31 def_bool !LEGACY_TIMER_TICK !! 30 bool 32 31 33 # Architecture can handle broadcast in a drive 32 # Architecture can handle broadcast in a driver-agnostic way 34 config ARCH_HAS_TICK_BROADCAST 33 config ARCH_HAS_TICK_BROADCAST 35 bool 34 bool 36 35 37 # Clockevents broadcasting infrastructure 36 # Clockevents broadcasting infrastructure 38 config GENERIC_CLOCKEVENTS_BROADCAST 37 config GENERIC_CLOCKEVENTS_BROADCAST 39 bool 38 bool 40 depends on GENERIC_CLOCKEVENTS 39 depends on GENERIC_CLOCKEVENTS 41 40 42 # Handle broadcast in default_idle_call() << 43 config GENERIC_CLOCKEVENTS_BROADCAST_IDLE << 44 bool << 45 depends on GENERIC_CLOCKEVENTS_BROADCA << 46 << 47 # Automatically adjust the min. reprogramming 41 # Automatically adjust the min. reprogramming time for 48 # clock event device 42 # clock event device 49 config GENERIC_CLOCKEVENTS_MIN_ADJUST 43 config GENERIC_CLOCKEVENTS_MIN_ADJUST 50 bool 44 bool 51 45 52 # Generic update of CMOS clock 46 # Generic update of CMOS clock 53 config GENERIC_CMOS_UPDATE 47 config GENERIC_CMOS_UPDATE 54 bool 48 bool 55 49 56 # Select to handle posix CPU timers from task_ << 57 # and not from the timer interrupt context << 58 config HAVE_POSIX_CPU_TIMERS_TASK_WORK << 59 bool << 60 << 61 config POSIX_CPU_TIMERS_TASK_WORK << 62 bool << 63 default y if POSIX_TIMERS && HAVE_POSI << 64 << 65 config LEGACY_TIMER_TICK << 66 bool << 67 help << 68 The legacy timer tick helper is used << 69 lack support for the generic clockev << 70 New platforms should use generic clo << 71 << 72 config TIME_KUNIT_TEST << 73 tristate "KUnit test for kernel/time f << 74 depends on KUNIT << 75 default KUNIT_ALL_TESTS << 76 help << 77 Enable this option to test RTC libra << 78 << 79 If unsure, say N. << 80 << 81 config CONTEXT_TRACKING << 82 bool << 83 << 84 config CONTEXT_TRACKING_IDLE << 85 bool << 86 select CONTEXT_TRACKING << 87 help << 88 Tracks idle state on behalf of RCU. << 89 << 90 if GENERIC_CLOCKEVENTS 50 if GENERIC_CLOCKEVENTS 91 menu "Timers subsystem" 51 menu "Timers subsystem" 92 52 93 # Core internal switch. Selected by NO_HZ_COMM 53 # Core internal switch. Selected by NO_HZ_COMMON / HIGH_RES_TIMERS. This is 94 # only related to the tick functionality. Ones 54 # only related to the tick functionality. Oneshot clockevent devices 95 # are supported independent of this. 55 # are supported independent of this. 96 config TICK_ONESHOT 56 config TICK_ONESHOT 97 bool 57 bool 98 58 99 config NO_HZ_COMMON 59 config NO_HZ_COMMON 100 bool 60 bool >> 61 depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS 101 select TICK_ONESHOT 62 select TICK_ONESHOT 102 63 103 choice 64 choice 104 prompt "Timer tick handling" 65 prompt "Timer tick handling" 105 default NO_HZ_IDLE if NO_HZ 66 default NO_HZ_IDLE if NO_HZ 106 67 107 config HZ_PERIODIC 68 config HZ_PERIODIC 108 bool "Periodic timer ticks (constant r 69 bool "Periodic timer ticks (constant rate, no dynticks)" 109 help 70 help 110 This option keeps the tick running p 71 This option keeps the tick running periodically at a constant 111 rate, even when the CPU doesn't need 72 rate, even when the CPU doesn't need it. 112 73 113 config NO_HZ_IDLE 74 config NO_HZ_IDLE 114 bool "Idle dynticks system (tickless i 75 bool "Idle dynticks system (tickless idle)" >> 76 depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS 115 select NO_HZ_COMMON 77 select NO_HZ_COMMON 116 help 78 help 117 This option enables a tickless idle 79 This option enables a tickless idle system: timer interrupts 118 will only trigger on an as-needed ba 80 will only trigger on an as-needed basis when the system is idle. 119 This is usually interesting for ener 81 This is usually interesting for energy saving. 120 82 121 Most of the time you want to say Y h 83 Most of the time you want to say Y here. 122 84 123 config NO_HZ_FULL 85 config NO_HZ_FULL 124 bool "Full dynticks system (tickless)" 86 bool "Full dynticks system (tickless)" 125 # NO_HZ_COMMON dependency 87 # NO_HZ_COMMON dependency >> 88 depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS 126 # We need at least one periodic CPU fo 89 # We need at least one periodic CPU for timekeeping 127 depends on SMP 90 depends on SMP 128 depends on HAVE_CONTEXT_TRACKING_USER !! 91 depends on HAVE_CONTEXT_TRACKING 129 # VIRT_CPU_ACCOUNTING_GEN dependency 92 # VIRT_CPU_ACCOUNTING_GEN dependency 130 depends on HAVE_VIRT_CPU_ACCOUNTING_GE 93 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN 131 select NO_HZ_COMMON 94 select NO_HZ_COMMON 132 select RCU_NOCB_CPU 95 select RCU_NOCB_CPU 133 select VIRT_CPU_ACCOUNTING_GEN 96 select VIRT_CPU_ACCOUNTING_GEN 134 select IRQ_WORK 97 select IRQ_WORK 135 select CPU_ISOLATION 98 select CPU_ISOLATION 136 help 99 help 137 Adaptively try to shutdown the tick w 100 Adaptively try to shutdown the tick whenever possible, even when 138 the CPU is running tasks. Typically t 101 the CPU is running tasks. Typically this requires running a single 139 task on the CPU. Chances for running 102 task on the CPU. Chances for running tickless are maximized when 140 the task mostly runs in userspace and 103 the task mostly runs in userspace and has few kernel activity. 141 104 142 You need to fill up the nohz_full boo 105 You need to fill up the nohz_full boot parameter with the 143 desired range of dynticks CPUs to use !! 106 desired range of dynticks CPUs. 144 the expense of some overhead in user << 145 syscalls, exceptions and interrupts. << 146 107 147 By default, without passing the nohz_ !! 108 This is implemented at the expense of some overhead in user <-> kernel 148 like NO_HZ_IDLE. !! 109 transitions: syscalls, exceptions and interrupts. Even when it's >> 110 dynamically off. 149 111 150 If you're a distro say Y. !! 112 Say N. 151 113 152 endchoice 114 endchoice 153 115 154 config CONTEXT_TRACKING_USER << 155 bool << 156 depends on HAVE_CONTEXT_TRACKING_USER << 157 select CONTEXT_TRACKING << 158 help << 159 Track transitions between kernel and << 160 tickless cputime accounting. The for << 161 tracking to enter/exit RCU extended << 162 << 163 config CONTEXT_TRACKING_USER_FORCE << 164 bool "Force user context tracking" << 165 depends on CONTEXT_TRACKING_USER << 166 default y if !NO_HZ_FULL << 167 help << 168 The major pre-requirement for full d << 169 support the user context tracking su << 170 other dependencies to provide in ord << 171 dynticks working. << 172 << 173 This option stands for testing when << 174 user context tracking backend but do << 175 requirements to make the full dyntic << 176 Without the full dynticks, there is << 177 for user context tracking and the su << 178 userspace extended quiescent state a << 179 accounting. This option copes with t << 180 dynticks subsystem by forcing the us << 181 CPUs in the system. << 182 << 183 Say Y only if you're working on the << 184 architecture backend for the user co << 185 << 186 Say N otherwise, this option brings << 187 don't want in production. << 188 << 189 config NO_HZ 116 config NO_HZ 190 bool "Old Idle dynticks config" 117 bool "Old Idle dynticks config" >> 118 depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS 191 help 119 help 192 This is the old config entry that en 120 This is the old config entry that enables dynticks idle. 193 We keep it around for a little while 121 We keep it around for a little while to enforce backward 194 compatibility with older config file 122 compatibility with older config files. 195 123 196 config HIGH_RES_TIMERS 124 config HIGH_RES_TIMERS 197 bool "High Resolution Timer Support" 125 bool "High Resolution Timer Support" >> 126 depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS 198 select TICK_ONESHOT 127 select TICK_ONESHOT 199 help 128 help 200 This option enables high resolution 129 This option enables high resolution timer support. If your 201 hardware is not capable then this op 130 hardware is not capable then this option only increases 202 the size of the kernel image. 131 the size of the kernel image. 203 << 204 config CLOCKSOURCE_WATCHDOG_MAX_SKEW_US << 205 int "Clocksource watchdog maximum allo << 206 depends on CLOCKSOURCE_WATCHDOG << 207 range 50 1000 << 208 default 125 << 209 help << 210 Specify the maximum amount of allowa << 211 microseconds before reporting the cl << 212 The default is based on a half-secon << 213 interval and NTP's maximum frequency << 214 per million. If the clocksource is << 215 it is good enough for the clocksourc << 216 132 217 endmenu 133 endmenu 218 endif 134 endif

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TOMOYO Linux Cross Reference
Linux/kernel/time/Kconfig

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Differences between /kernel/time/Kconfig (Version linux-6.12-rc7) and /kernel/time/Kconfig (Version linux-4.18.20)

TOMOYO Linux Cross Reference Linux/kernel/time/Kconfig

Diff markup

Differences between /kernel/time/Kconfig (Version linux-6.12-rc7) and /kernel/time/Kconfig (Version linux-4.18.20)

TOMOYO Linux Cross Reference
Linux/kernel/time/Kconfig