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Commit | Line | Data |
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79bf2bb3 TG |
1 | # |
2 | # Timer subsystem related configuration options | |
3 | # | |
3872c48b | 4 | |
b5e498ad TG |
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 | ||
05ad717c | 15 | # Platforms has a persistent clock |
6f16eebe | 16 | config ALWAYS_USE_PERSISTENT_CLOCK |
05ad717c FT |
17 | bool |
18 | default n | |
19 | ||
576094b7 JS |
20 | # Timekeeping vsyscall support |
21 | config GENERIC_TIME_VSYSCALL | |
22 | bool | |
23 | ||
b5e498ad | 24 | # Timekeeping vsyscall support |
70639421 | 25 | config GENERIC_TIME_VSYSCALL_OLD |
b5e498ad TG |
26 | bool |
27 | ||
28 | # ktime_t scalar 64bit nsec representation | |
29 | config KTIME_SCALAR | |
30 | bool | |
31 | ||
32 | # Old style timekeeping | |
33 | config ARCH_USES_GETTIMEOFFSET | |
34 | bool | |
35 | ||
36 | # The generic clock events infrastructure | |
37 | config GENERIC_CLOCKEVENTS | |
38 | bool | |
39 | ||
764e0da1 TG |
40 | # Migration helper. Builds, but does not invoke |
41 | config GENERIC_CLOCKEVENTS_BUILD | |
42 | bool | |
43 | default y | |
44 | depends on GENERIC_CLOCKEVENTS | |
45 | ||
12ad1000 MR |
46 | # Architecture can handle broadcast in a driver-agnostic way |
47 | config ARCH_HAS_TICK_BROADCAST | |
48 | bool | |
49 | ||
b5e498ad TG |
50 | # Clockevents broadcasting infrastructure |
51 | config GENERIC_CLOCKEVENTS_BROADCAST | |
52 | bool | |
53 | depends on GENERIC_CLOCKEVENTS | |
54 | ||
764e0da1 TG |
55 | # Automatically adjust the min. reprogramming time for |
56 | # clock event device | |
57 | config GENERIC_CLOCKEVENTS_MIN_ADJUST | |
58 | bool | |
59 | ||
b5e498ad TG |
60 | # Generic update of CMOS clock |
61 | config GENERIC_CMOS_UPDATE | |
62 | bool | |
764e0da1 TG |
63 | |
64 | if GENERIC_CLOCKEVENTS | |
65 | menu "Timers subsystem" | |
66 | ||
3451d024 | 67 | # Core internal switch. Selected by NO_HZ_COMMON / HIGH_RES_TIMERS. This is |
764e0da1 TG |
68 | # only related to the tick functionality. Oneshot clockevent devices |
69 | # are supported independ of this. | |
70 | config TICK_ONESHOT | |
71 | bool | |
72 | ||
3451d024 FW |
73 | config NO_HZ_COMMON |
74 | bool | |
75 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS | |
76 | select TICK_ONESHOT | |
77 | ||
3ca277e4 | 78 | # Kept around for compatibility, maps to NO_HZ_IDLE |
764e0da1 | 79 | config NO_HZ |
3ca277e4 FW |
80 | bool |
81 | ||
82 | choice | |
83 | prompt "Timer tick handling" | |
84 | default NO_HZ_IDLE if NO_HZ | |
85 | ||
86 | config PERIODIC_HZ | |
87 | bool "Periodic timer ticks (constant rate, no dynticks)" | |
88 | help | |
89 | This option keeps the tick running periodically at a constant | |
90 | rate, even when the CPU doesn't need it. | |
91 | ||
92 | config NO_HZ_IDLE | |
93 | bool "Idle dynticks system (tickless idle)" | |
764e0da1 | 94 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS |
3451d024 | 95 | select NO_HZ_COMMON |
764e0da1 | 96 | help |
3ca277e4 FW |
97 | This option enables a tickless idle system: timer interrupts |
98 | will only trigger on an as-needed basis when the system is idle. | |
99 | This is usually interesting for energy saving. | |
100 | ||
101 | Most of the time you want to say Y here. | |
764e0da1 | 102 | |
a831881b | 103 | config NO_HZ_EXTENDED |
3ca277e4 | 104 | bool "Full dynticks system (tickless single task)" |
3451d024 | 105 | # NO_HZ_COMMON dependency |
ab71d36d FW |
106 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS |
107 | # RCU_USER_QS | |
108 | depends on HAVE_CONTEXT_TRACKING && SMP | |
109 | # RCU_NOCB_CPU dependency | |
110 | depends on TREE_RCU || TREE_PREEMPT_RCU | |
111 | depends on VIRT_CPU_ACCOUNTING_GEN | |
3451d024 | 112 | select NO_HZ_COMMON |
ab71d36d FW |
113 | select RCU_USER_QS |
114 | select RCU_NOCB_CPU | |
115 | select CONTEXT_TRACKING_FORCE | |
116 | help | |
117 | Adaptively try to shutdown the tick whenever possible, even when | |
a831881b FW |
118 | the CPU is running tasks. Typically this requires running a single |
119 | task on the CPU. Chances for running tickless are maximized when | |
120 | the task mostly runs in userspace and has few kernel activity. | |
121 | ||
122 | You need to fill up the nohz_extended boot parameter with the | |
123 | desired range of dynticks CPUs. | |
124 | ||
125 | This is implemented at the expense of some overhead in user <-> kernel | |
126 | transitions: syscalls, exceptions and interrupts. Even when it's | |
127 | dynamically off. | |
128 | ||
129 | Say N. | |
130 | ||
3ca277e4 FW |
131 | endchoice |
132 | ||
764e0da1 TG |
133 | config HIGH_RES_TIMERS |
134 | bool "High Resolution Timer Support" | |
135 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS | |
136 | select TICK_ONESHOT | |
137 | help | |
138 | This option enables high resolution timer support. If your | |
139 | hardware is not capable then this option only increases | |
140 | the size of the kernel image. | |
141 | ||
142 | endmenu | |
143 | endif |