Thomas Gleixner | 79bf2bb | 2007-02-16 01:28:03 -0800 | [diff] [blame] | 1 | # |
| 2 | # Timer subsystem related configuration options |
| 3 | # |
Thomas Gleixner | 3872c48 | 2012-03-31 12:45:43 +0200 | [diff] [blame] | 4 | |
Thomas Gleixner | b5e498a | 2012-05-18 09:59:57 +0200 | [diff] [blame] | 5 | # Options selectable by arch Kconfig |
| 6 | |
| 7 | # Watchdog function for clocksources to detect instabilities |
| 8 | config CLOCKSOURCE_WATCHDOG |
| 9 | bool |
| 10 | |
| 11 | # Architecture has extra clocksource data |
| 12 | config ARCH_CLOCKSOURCE_DATA |
| 13 | bool |
| 14 | |
| 15 | # Timekeeping vsyscall support |
John Stultz | 576094b | 2012-09-11 19:58:13 -0400 | [diff] [blame] | 16 | config GENERIC_TIME_VSYSCALL |
| 17 | bool |
| 18 | |
| 19 | # Timekeeping vsyscall support |
John Stultz | 7063942 | 2012-09-04 15:34:21 -0400 | [diff] [blame] | 20 | config GENERIC_TIME_VSYSCALL_OLD |
Thomas Gleixner | b5e498a | 2012-05-18 09:59:57 +0200 | [diff] [blame] | 21 | bool |
| 22 | |
| 23 | # ktime_t scalar 64bit nsec representation |
| 24 | config KTIME_SCALAR |
| 25 | bool |
| 26 | |
| 27 | # Old style timekeeping |
| 28 | config ARCH_USES_GETTIMEOFFSET |
| 29 | bool |
| 30 | |
| 31 | # The generic clock events infrastructure |
| 32 | config GENERIC_CLOCKEVENTS |
| 33 | bool |
| 34 | |
Thomas Gleixner | 764e0da | 2012-05-21 23:16:18 +0200 | [diff] [blame] | 35 | # Migration helper. Builds, but does not invoke |
| 36 | config GENERIC_CLOCKEVENTS_BUILD |
| 37 | bool |
| 38 | default y |
| 39 | depends on GENERIC_CLOCKEVENTS |
| 40 | |
Mark Rutland | 12ad100 | 2013-01-14 17:05:22 +0000 | [diff] [blame] | 41 | # Architecture can handle broadcast in a driver-agnostic way |
| 42 | config ARCH_HAS_TICK_BROADCAST |
| 43 | bool |
| 44 | |
Thomas Gleixner | b5e498a | 2012-05-18 09:59:57 +0200 | [diff] [blame] | 45 | # Clockevents broadcasting infrastructure |
| 46 | config GENERIC_CLOCKEVENTS_BROADCAST |
| 47 | bool |
| 48 | depends on GENERIC_CLOCKEVENTS |
| 49 | |
Thomas Gleixner | 764e0da | 2012-05-21 23:16:18 +0200 | [diff] [blame] | 50 | # Automatically adjust the min. reprogramming time for |
| 51 | # clock event device |
| 52 | config GENERIC_CLOCKEVENTS_MIN_ADJUST |
| 53 | bool |
| 54 | |
Thomas Gleixner | b5e498a | 2012-05-18 09:59:57 +0200 | [diff] [blame] | 55 | # Generic update of CMOS clock |
| 56 | config GENERIC_CMOS_UPDATE |
| 57 | bool |
Thomas Gleixner | 764e0da | 2012-05-21 23:16:18 +0200 | [diff] [blame] | 58 | |
| 59 | if GENERIC_CLOCKEVENTS |
| 60 | menu "Timers subsystem" |
| 61 | |
Frederic Weisbecker | 3451d02 | 2011-08-10 23:21:01 +0200 | [diff] [blame] | 62 | # Core internal switch. Selected by NO_HZ_COMMON / HIGH_RES_TIMERS. This is |
Thomas Gleixner | 764e0da | 2012-05-21 23:16:18 +0200 | [diff] [blame] | 63 | # only related to the tick functionality. Oneshot clockevent devices |
| 64 | # are supported independ of this. |
| 65 | config TICK_ONESHOT |
| 66 | bool |
| 67 | |
Frederic Weisbecker | 3451d02 | 2011-08-10 23:21:01 +0200 | [diff] [blame] | 68 | config NO_HZ_COMMON |
| 69 | bool |
| 70 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS |
| 71 | select TICK_ONESHOT |
| 72 | |
Frederic Weisbecker | 3ca277e | 2011-08-10 23:21:01 +0200 | [diff] [blame] | 73 | choice |
| 74 | prompt "Timer tick handling" |
| 75 | default NO_HZ_IDLE if NO_HZ |
| 76 | |
Frederic Weisbecker | 5b533f4 | 2013-04-13 16:53:35 +0200 | [diff] [blame] | 77 | config HZ_PERIODIC |
Frederic Weisbecker | 3ca277e | 2011-08-10 23:21:01 +0200 | [diff] [blame] | 78 | bool "Periodic timer ticks (constant rate, no dynticks)" |
| 79 | help |
| 80 | This option keeps the tick running periodically at a constant |
| 81 | rate, even when the CPU doesn't need it. |
| 82 | |
| 83 | config NO_HZ_IDLE |
| 84 | bool "Idle dynticks system (tickless idle)" |
Thomas Gleixner | 764e0da | 2012-05-21 23:16:18 +0200 | [diff] [blame] | 85 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS |
Frederic Weisbecker | 3451d02 | 2011-08-10 23:21:01 +0200 | [diff] [blame] | 86 | select NO_HZ_COMMON |
Thomas Gleixner | 764e0da | 2012-05-21 23:16:18 +0200 | [diff] [blame] | 87 | help |
Frederic Weisbecker | 3ca277e | 2011-08-10 23:21:01 +0200 | [diff] [blame] | 88 | This option enables a tickless idle system: timer interrupts |
| 89 | will only trigger on an as-needed basis when the system is idle. |
| 90 | This is usually interesting for energy saving. |
| 91 | |
| 92 | Most of the time you want to say Y here. |
Thomas Gleixner | 764e0da | 2012-05-21 23:16:18 +0200 | [diff] [blame] | 93 | |
Frederic Weisbecker | c5bfece | 2013-04-12 16:45:34 +0200 | [diff] [blame] | 94 | config NO_HZ_FULL |
Frederic Weisbecker | fae30dd | 2013-04-13 17:04:04 +0200 | [diff] [blame] | 95 | bool "Full dynticks system (tickless)" |
Frederic Weisbecker | 3451d02 | 2011-08-10 23:21:01 +0200 | [diff] [blame] | 96 | # NO_HZ_COMMON dependency |
Frederic Weisbecker | ab71d36 | 2011-08-10 23:21:01 +0200 | [diff] [blame] | 97 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS |
Frederic Weisbecker | fae30dd | 2013-04-13 17:04:04 +0200 | [diff] [blame] | 98 | # We need at least one periodic CPU for timekeeping |
| 99 | depends on SMP |
| 100 | # RCU_USER_QS dependency |
| 101 | depends on HAVE_CONTEXT_TRACKING |
Frederic Weisbecker | c58b0df | 2013-04-26 15:16:31 +0200 | [diff] [blame] | 102 | # VIRT_CPU_ACCOUNTING_GEN dependency |
| 103 | depends on 64BIT |
Frederic Weisbecker | 3451d02 | 2011-08-10 23:21:01 +0200 | [diff] [blame] | 104 | select NO_HZ_COMMON |
Frederic Weisbecker | ab71d36 | 2011-08-10 23:21:01 +0200 | [diff] [blame] | 105 | select RCU_USER_QS |
| 106 | select RCU_NOCB_CPU |
Frederic Weisbecker | c58b0df | 2013-04-26 15:16:31 +0200 | [diff] [blame] | 107 | select VIRT_CPU_ACCOUNTING_GEN |
Frederic Weisbecker | ab71d36 | 2011-08-10 23:21:01 +0200 | [diff] [blame] | 108 | select CONTEXT_TRACKING_FORCE |
Frederic Weisbecker | 76c24fb | 2013-04-18 00:15:40 +0200 | [diff] [blame] | 109 | select IRQ_WORK |
Frederic Weisbecker | ab71d36 | 2011-08-10 23:21:01 +0200 | [diff] [blame] | 110 | help |
| 111 | Adaptively try to shutdown the tick whenever possible, even when |
Frederic Weisbecker | a831881 | 2012-12-18 17:32:19 +0100 | [diff] [blame] | 112 | the CPU is running tasks. Typically this requires running a single |
| 113 | task on the CPU. Chances for running tickless are maximized when |
| 114 | the task mostly runs in userspace and has few kernel activity. |
| 115 | |
Frederic Weisbecker | c5bfece | 2013-04-12 16:45:34 +0200 | [diff] [blame] | 116 | You need to fill up the nohz_full boot parameter with the |
Frederic Weisbecker | a831881 | 2012-12-18 17:32:19 +0100 | [diff] [blame] | 117 | desired range of dynticks CPUs. |
| 118 | |
| 119 | This is implemented at the expense of some overhead in user <-> kernel |
| 120 | transitions: syscalls, exceptions and interrupts. Even when it's |
| 121 | dynamically off. |
| 122 | |
| 123 | Say N. |
| 124 | |
Frederic Weisbecker | 3ca277e | 2011-08-10 23:21:01 +0200 | [diff] [blame] | 125 | endchoice |
| 126 | |
Frederic Weisbecker | f98823a | 2013-03-27 01:17:22 +0100 | [diff] [blame] | 127 | config NO_HZ_FULL_ALL |
| 128 | bool "Full dynticks system on all CPUs by default" |
| 129 | depends on NO_HZ_FULL |
| 130 | help |
| 131 | If the user doesn't pass the nohz_full boot option to |
| 132 | define the range of full dynticks CPUs, consider that all |
| 133 | CPUs in the system are full dynticks by default. |
| 134 | Note the boot CPU will still be kept outside the range to |
| 135 | handle the timekeeping duty. |
| 136 | |
Frederic Weisbecker | 0644ca5 | 2013-04-12 16:40:12 +0200 | [diff] [blame] | 137 | config NO_HZ |
| 138 | bool "Old Idle dynticks config" |
| 139 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS |
| 140 | help |
| 141 | This is the old config entry that enables dynticks idle. |
| 142 | We keep it around for a little while to enforce backward |
| 143 | compatibility with older config files. |
| 144 | |
Thomas Gleixner | 764e0da | 2012-05-21 23:16:18 +0200 | [diff] [blame] | 145 | config HIGH_RES_TIMERS |
| 146 | bool "High Resolution Timer Support" |
| 147 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS |
| 148 | select TICK_ONESHOT |
| 149 | help |
| 150 | This option enables high resolution timer support. If your |
| 151 | hardware is not capable then this option only increases |
| 152 | the size of the kernel image. |
| 153 | |
| 154 | endmenu |
| 155 | endif |