1 # SPDX-License-Identifier: GPL-2.0-only 2 # 3 # Timer subsystem related configuration option 4 # 5 6 # Options selectable by arch Kconfig 7 8 # Watchdog function for clocksources to detect 9 config CLOCKSOURCE_WATCHDOG 10 bool 11 12 # Architecture has extra clocksource data 13 config ARCH_CLOCKSOURCE_DATA 14 bool 15 16 # Architecture has extra clocksource init call 17 config ARCH_CLOCKSOURCE_INIT 18 bool 19 20 # Clocksources require validation of the clock 21 # cycle update - x86/TSC misfeature 22 config CLOCKSOURCE_VALIDATE_LAST_CYCLE 23 bool 24 25 # Timekeeping vsyscall support 26 config GENERIC_TIME_VSYSCALL 27 bool 28 29 # The generic clock events infrastructure 30 config GENERIC_CLOCKEVENTS 31 def_bool !LEGACY_TIMER_TICK 32 33 # Architecture can handle broadcast in a drive 34 config ARCH_HAS_TICK_BROADCAST 35 bool 36 37 # Clockevents broadcasting infrastructure 38 config GENERIC_CLOCKEVENTS_BROADCAST 39 bool 40 depends on GENERIC_CLOCKEVENTS 41 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 48 # clock event device 49 config GENERIC_CLOCKEVENTS_MIN_ADJUST 50 bool 51 52 # Generic update of CMOS clock 53 config GENERIC_CMOS_UPDATE 54 bool 55 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 91 menu "Timers subsystem" 92 93 # Core internal switch. Selected by NO_HZ_COMM 94 # only related to the tick functionality. Ones 95 # are supported independent of this. 96 config TICK_ONESHOT 97 bool 98 99 config NO_HZ_COMMON 100 bool 101 select TICK_ONESHOT 102 103 choice 104 prompt "Timer tick handling" 105 default NO_HZ_IDLE if NO_HZ 106 107 config HZ_PERIODIC 108 bool "Periodic timer ticks (constant r 109 help 110 This option keeps the tick running p 111 rate, even when the CPU doesn't need 112 113 config NO_HZ_IDLE 114 bool "Idle dynticks system (tickless i 115 select NO_HZ_COMMON 116 help 117 This option enables a tickless idle 118 will only trigger on an as-needed ba 119 This is usually interesting for ener 120 121 Most of the time you want to say Y h 122 123 config NO_HZ_FULL 124 bool "Full dynticks system (tickless)" 125 # NO_HZ_COMMON dependency 126 # We need at least one periodic CPU fo 127 depends on SMP 128 depends on HAVE_CONTEXT_TRACKING_USER 129 # VIRT_CPU_ACCOUNTING_GEN dependency 130 depends on HAVE_VIRT_CPU_ACCOUNTING_GE 131 select NO_HZ_COMMON 132 select RCU_NOCB_CPU 133 select VIRT_CPU_ACCOUNTING_GEN 134 select IRQ_WORK 135 select CPU_ISOLATION 136 help 137 Adaptively try to shutdown the tick w 138 the CPU is running tasks. Typically t 139 task on the CPU. Chances for running 140 the task mostly runs in userspace and 141 142 You need to fill up the nohz_full boo 143 desired range of dynticks CPUs to use 144 the expense of some overhead in user 145 syscalls, exceptions and interrupts. 146 147 By default, without passing the nohz_ 148 like NO_HZ_IDLE. 149 150 If you're a distro say Y. 151 152 endchoice 153 154 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 190 bool "Old Idle dynticks config" 191 help 192 This is the old config entry that en 193 We keep it around for a little while 194 compatibility with older config file 195 196 config HIGH_RES_TIMERS 197 bool "High Resolution Timer Support" 198 select TICK_ONESHOT 199 help 200 This option enables high resolution 201 hardware is not capable then this op 202 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 216 217 endmenu 218 endif
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