179bf2bb3SThomas Gleixner# 279bf2bb3SThomas Gleixner# Timer subsystem related configuration options 379bf2bb3SThomas Gleixner# 43872c48bSThomas Gleixner 5b5e498adSThomas Gleixner# Options selectable by arch Kconfig 6b5e498adSThomas Gleixner 7b5e498adSThomas Gleixner# Watchdog function for clocksources to detect instabilities 8b5e498adSThomas Gleixnerconfig CLOCKSOURCE_WATCHDOG 9b5e498adSThomas Gleixner bool 10b5e498adSThomas Gleixner 11b5e498adSThomas Gleixner# Architecture has extra clocksource data 12b5e498adSThomas Gleixnerconfig ARCH_CLOCKSOURCE_DATA 13b5e498adSThomas Gleixner bool 14b5e498adSThomas Gleixner 1505ad717cSFeng Tang# Platforms has a persistent clock 166f16eebeSJohn Stultzconfig ALWAYS_USE_PERSISTENT_CLOCK 1705ad717cSFeng Tang bool 1805ad717cSFeng Tang default n 1905ad717cSFeng Tang 20b5e498adSThomas Gleixner# Timekeeping vsyscall support 21576094b7SJohn Stultzconfig GENERIC_TIME_VSYSCALL 22576094b7SJohn Stultz bool 23576094b7SJohn Stultz 24576094b7SJohn Stultz# Timekeeping vsyscall support 2570639421SJohn Stultzconfig GENERIC_TIME_VSYSCALL_OLD 26b5e498adSThomas Gleixner bool 27b5e498adSThomas Gleixner 28b5e498adSThomas Gleixner# ktime_t scalar 64bit nsec representation 29b5e498adSThomas Gleixnerconfig KTIME_SCALAR 30b5e498adSThomas Gleixner bool 31b5e498adSThomas Gleixner 32b5e498adSThomas Gleixner# Old style timekeeping 33b5e498adSThomas Gleixnerconfig ARCH_USES_GETTIMEOFFSET 34b5e498adSThomas Gleixner bool 35b5e498adSThomas Gleixner 36b5e498adSThomas Gleixner# The generic clock events infrastructure 37b5e498adSThomas Gleixnerconfig GENERIC_CLOCKEVENTS 38b5e498adSThomas Gleixner bool 39b5e498adSThomas Gleixner 40764e0da1SThomas Gleixner# Migration helper. Builds, but does not invoke 41764e0da1SThomas Gleixnerconfig GENERIC_CLOCKEVENTS_BUILD 42764e0da1SThomas Gleixner bool 43764e0da1SThomas Gleixner default y 44764e0da1SThomas Gleixner depends on GENERIC_CLOCKEVENTS 45764e0da1SThomas Gleixner 4612ad1000SMark Rutland# Architecture can handle broadcast in a driver-agnostic way 4712ad1000SMark Rutlandconfig ARCH_HAS_TICK_BROADCAST 4812ad1000SMark Rutland bool 4912ad1000SMark Rutland 50b5e498adSThomas Gleixner# Clockevents broadcasting infrastructure 51b5e498adSThomas Gleixnerconfig GENERIC_CLOCKEVENTS_BROADCAST 52b5e498adSThomas Gleixner bool 53b5e498adSThomas Gleixner depends on GENERIC_CLOCKEVENTS 54b5e498adSThomas Gleixner 55764e0da1SThomas Gleixner# Automatically adjust the min. reprogramming time for 56764e0da1SThomas Gleixner# clock event device 57764e0da1SThomas Gleixnerconfig GENERIC_CLOCKEVENTS_MIN_ADJUST 58764e0da1SThomas Gleixner bool 59764e0da1SThomas Gleixner 60b5e498adSThomas Gleixner# Generic update of CMOS clock 61b5e498adSThomas Gleixnerconfig GENERIC_CMOS_UPDATE 62b5e498adSThomas Gleixner bool 63764e0da1SThomas Gleixner 64764e0da1SThomas Gleixnerif GENERIC_CLOCKEVENTS 65764e0da1SThomas Gleixnermenu "Timers subsystem" 66764e0da1SThomas Gleixner 67764e0da1SThomas Gleixner# Core internal switch. Selected by NO_HZ / HIGH_RES_TIMERS. This is 68764e0da1SThomas Gleixner# only related to the tick functionality. Oneshot clockevent devices 69764e0da1SThomas Gleixner# are supported independ of this. 70764e0da1SThomas Gleixnerconfig TICK_ONESHOT 71764e0da1SThomas Gleixner bool 72764e0da1SThomas Gleixner 73764e0da1SThomas Gleixnerconfig NO_HZ 74764e0da1SThomas Gleixner bool "Tickless System (Dynamic Ticks)" 75764e0da1SThomas Gleixner depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS 76764e0da1SThomas Gleixner select TICK_ONESHOT 77764e0da1SThomas Gleixner help 78764e0da1SThomas Gleixner This option enables a tickless system: timer interrupts will 79764e0da1SThomas Gleixner only trigger on an as-needed basis both when the system is 80764e0da1SThomas Gleixner busy and when the system is idle. 81764e0da1SThomas Gleixner 82a831881bSFrederic Weisbeckerconfig NO_HZ_EXTENDED 83a831881bSFrederic Weisbecker bool "Full dynticks system" 84*ab71d36dSFrederic Weisbecker # NO_HZ dependency 85*ab71d36dSFrederic Weisbecker depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS 86*ab71d36dSFrederic Weisbecker # RCU_USER_QS 87*ab71d36dSFrederic Weisbecker depends on HAVE_CONTEXT_TRACKING && SMP 88*ab71d36dSFrederic Weisbecker # RCU_NOCB_CPU dependency 89*ab71d36dSFrederic Weisbecker depends on TREE_RCU || TREE_PREEMPT_RCU 90*ab71d36dSFrederic Weisbecker depends on VIRT_CPU_ACCOUNTING_GEN 91*ab71d36dSFrederic Weisbecker select NO_HZ 92*ab71d36dSFrederic Weisbecker select RCU_USER_QS 93*ab71d36dSFrederic Weisbecker select RCU_NOCB_CPU 94a831881bSFrederic Weisbecker select CONTEXT_TRACKING_FORCE 95a831881bSFrederic Weisbecker help 96a831881bSFrederic Weisbecker Adaptively try to shutdown the tick whenever possible, even when 97a831881bSFrederic Weisbecker the CPU is running tasks. Typically this requires running a single 98a831881bSFrederic Weisbecker task on the CPU. Chances for running tickless are maximized when 99a831881bSFrederic Weisbecker the task mostly runs in userspace and has few kernel activity. 100a831881bSFrederic Weisbecker 101a831881bSFrederic Weisbecker You need to fill up the nohz_extended boot parameter with the 102a831881bSFrederic Weisbecker desired range of dynticks CPUs. 103a831881bSFrederic Weisbecker 104a831881bSFrederic Weisbecker This is implemented at the expense of some overhead in user <-> kernel 105a831881bSFrederic Weisbecker transitions: syscalls, exceptions and interrupts. Even when it's 106a831881bSFrederic Weisbecker dynamically off. 107a831881bSFrederic Weisbecker 108a831881bSFrederic Weisbecker Say N. 109a831881bSFrederic Weisbecker 110764e0da1SThomas Gleixnerconfig HIGH_RES_TIMERS 111764e0da1SThomas Gleixner bool "High Resolution Timer Support" 112764e0da1SThomas Gleixner depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS 113764e0da1SThomas Gleixner select TICK_ONESHOT 114764e0da1SThomas Gleixner help 115764e0da1SThomas Gleixner This option enables high resolution timer support. If your 116764e0da1SThomas Gleixner hardware is not capable then this option only increases 117764e0da1SThomas Gleixner the size of the kernel image. 118764e0da1SThomas Gleixner 119764e0da1SThomas Gleixnerendmenu 120764e0da1SThomas Gleixnerendif 121