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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 | ||
09ec5442 TG |
15 | # Clocksources require validation of the clocksource against the last |
16 | # cycle update - x86/TSC misfeature | |
17 | config CLOCKSOURCE_VALIDATE_LAST_CYCLE | |
18 | bool | |
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 | ||
b5e498ad TG |
28 | # Old style timekeeping |
29 | config ARCH_USES_GETTIMEOFFSET | |
30 | bool | |
31 | ||
32 | # The generic clock events infrastructure | |
33 | config GENERIC_CLOCKEVENTS | |
34 | bool | |
35 | ||
12ad1000 MR |
36 | # Architecture can handle broadcast in a driver-agnostic way |
37 | config ARCH_HAS_TICK_BROADCAST | |
38 | bool | |
39 | ||
b5e498ad TG |
40 | # Clockevents broadcasting infrastructure |
41 | config GENERIC_CLOCKEVENTS_BROADCAST | |
42 | bool | |
43 | depends on GENERIC_CLOCKEVENTS | |
44 | ||
764e0da1 TG |
45 | # Automatically adjust the min. reprogramming time for |
46 | # clock event device | |
47 | config GENERIC_CLOCKEVENTS_MIN_ADJUST | |
48 | bool | |
49 | ||
b5e498ad TG |
50 | # Generic update of CMOS clock |
51 | config GENERIC_CMOS_UPDATE | |
52 | bool | |
764e0da1 TG |
53 | |
54 | if GENERIC_CLOCKEVENTS | |
55 | menu "Timers subsystem" | |
56 | ||
3451d024 | 57 | # Core internal switch. Selected by NO_HZ_COMMON / HIGH_RES_TIMERS. This is |
764e0da1 TG |
58 | # only related to the tick functionality. Oneshot clockevent devices |
59 | # are supported independ of this. | |
60 | config TICK_ONESHOT | |
61 | bool | |
62 | ||
3451d024 FW |
63 | config NO_HZ_COMMON |
64 | bool | |
65 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS | |
66 | select TICK_ONESHOT | |
67 | ||
3ca277e4 FW |
68 | choice |
69 | prompt "Timer tick handling" | |
70 | default NO_HZ_IDLE if NO_HZ | |
71 | ||
5b533f4f | 72 | config HZ_PERIODIC |
3ca277e4 FW |
73 | bool "Periodic timer ticks (constant rate, no dynticks)" |
74 | help | |
75 | This option keeps the tick running periodically at a constant | |
76 | rate, even when the CPU doesn't need it. | |
77 | ||
78 | config NO_HZ_IDLE | |
79 | bool "Idle dynticks system (tickless idle)" | |
764e0da1 | 80 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS |
3451d024 | 81 | select NO_HZ_COMMON |
764e0da1 | 82 | help |
3ca277e4 FW |
83 | This option enables a tickless idle system: timer interrupts |
84 | will only trigger on an as-needed basis when the system is idle. | |
85 | This is usually interesting for energy saving. | |
86 | ||
87 | Most of the time you want to say Y here. | |
764e0da1 | 88 | |
c5bfece2 | 89 | config NO_HZ_FULL |
fae30dd6 | 90 | bool "Full dynticks system (tickless)" |
3451d024 | 91 | # NO_HZ_COMMON dependency |
ab71d36d | 92 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS |
fae30dd6 FW |
93 | # We need at least one periodic CPU for timekeeping |
94 | depends on SMP | |
fae30dd6 | 95 | depends on HAVE_CONTEXT_TRACKING |
c58b0df1 | 96 | # VIRT_CPU_ACCOUNTING_GEN dependency |
554b0004 | 97 | depends on HAVE_VIRT_CPU_ACCOUNTING_GEN |
3451d024 | 98 | select NO_HZ_COMMON |
ab71d36d | 99 | select RCU_NOCB_CPU |
c58b0df1 | 100 | select VIRT_CPU_ACCOUNTING_GEN |
76c24fb0 | 101 | select IRQ_WORK |
ab71d36d FW |
102 | help |
103 | Adaptively try to shutdown the tick whenever possible, even when | |
a831881b FW |
104 | the CPU is running tasks. Typically this requires running a single |
105 | task on the CPU. Chances for running tickless are maximized when | |
106 | the task mostly runs in userspace and has few kernel activity. | |
107 | ||
c5bfece2 | 108 | You need to fill up the nohz_full boot parameter with the |
a831881b FW |
109 | desired range of dynticks CPUs. |
110 | ||
111 | This is implemented at the expense of some overhead in user <-> kernel | |
112 | transitions: syscalls, exceptions and interrupts. Even when it's | |
113 | dynamically off. | |
114 | ||
115 | Say N. | |
116 | ||
3ca277e4 FW |
117 | endchoice |
118 | ||
f98823ac | 119 | config NO_HZ_FULL_ALL |
f96a34e2 | 120 | bool "Full dynticks system on all CPUs by default (except CPU 0)" |
f98823ac FW |
121 | depends on NO_HZ_FULL |
122 | help | |
123 | If the user doesn't pass the nohz_full boot option to | |
124 | define the range of full dynticks CPUs, consider that all | |
125 | CPUs in the system are full dynticks by default. | |
126 | Note the boot CPU will still be kept outside the range to | |
127 | handle the timekeeping duty. | |
128 | ||
0644ca5c FW |
129 | config NO_HZ |
130 | bool "Old Idle dynticks config" | |
131 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS | |
132 | help | |
133 | This is the old config entry that enables dynticks idle. | |
134 | We keep it around for a little while to enforce backward | |
135 | compatibility with older config files. | |
136 | ||
764e0da1 TG |
137 | config HIGH_RES_TIMERS |
138 | bool "High Resolution Timer Support" | |
139 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS | |
140 | select TICK_ONESHOT | |
141 | help | |
142 | This option enables high resolution timer support. If your | |
143 | hardware is not capable then this option only increases | |
144 | the size of the kernel image. | |
145 | ||
146 | endmenu | |
147 | endif |