Commit | Line | Data |
---|---|---|
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 FW |
78 | choice |
79 | prompt "Timer tick handling" | |
80 | default NO_HZ_IDLE if NO_HZ | |
81 | ||
5b533f4f | 82 | config HZ_PERIODIC |
3ca277e4 FW |
83 | bool "Periodic timer ticks (constant rate, no dynticks)" |
84 | help | |
85 | This option keeps the tick running periodically at a constant | |
86 | rate, even when the CPU doesn't need it. | |
87 | ||
88 | config NO_HZ_IDLE | |
89 | bool "Idle dynticks system (tickless idle)" | |
764e0da1 | 90 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS |
3451d024 | 91 | select NO_HZ_COMMON |
764e0da1 | 92 | help |
3ca277e4 FW |
93 | This option enables a tickless idle system: timer interrupts |
94 | will only trigger on an as-needed basis when the system is idle. | |
95 | This is usually interesting for energy saving. | |
96 | ||
97 | Most of the time you want to say Y here. | |
764e0da1 | 98 | |
c5bfece2 | 99 | config NO_HZ_FULL |
fae30dd6 | 100 | bool "Full dynticks system (tickless)" |
3451d024 | 101 | # NO_HZ_COMMON dependency |
ab71d36d | 102 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS |
fae30dd6 FW |
103 | # We need at least one periodic CPU for timekeeping |
104 | depends on SMP | |
105 | # RCU_USER_QS dependency | |
106 | depends on HAVE_CONTEXT_TRACKING | |
ab71d36d | 107 | depends on VIRT_CPU_ACCOUNTING_GEN |
3451d024 | 108 | select NO_HZ_COMMON |
ab71d36d FW |
109 | select RCU_USER_QS |
110 | select RCU_NOCB_CPU | |
0637e029 | 111 | select RCU_NOCB_CPU_ALL |
ab71d36d | 112 | select CONTEXT_TRACKING_FORCE |
76c24fb0 | 113 | select IRQ_WORK |
ab71d36d FW |
114 | help |
115 | Adaptively try to shutdown the tick whenever possible, even when | |
a831881b FW |
116 | the CPU is running tasks. Typically this requires running a single |
117 | task on the CPU. Chances for running tickless are maximized when | |
118 | the task mostly runs in userspace and has few kernel activity. | |
119 | ||
c5bfece2 | 120 | You need to fill up the nohz_full boot parameter with the |
a831881b FW |
121 | desired range of dynticks CPUs. |
122 | ||
123 | This is implemented at the expense of some overhead in user <-> kernel | |
124 | transitions: syscalls, exceptions and interrupts. Even when it's | |
125 | dynamically off. | |
126 | ||
127 | Say N. | |
128 | ||
3ca277e4 FW |
129 | endchoice |
130 | ||
f98823ac FW |
131 | config NO_HZ_FULL_ALL |
132 | bool "Full dynticks system on all CPUs by default" | |
133 | depends on NO_HZ_FULL | |
134 | help | |
135 | If the user doesn't pass the nohz_full boot option to | |
136 | define the range of full dynticks CPUs, consider that all | |
137 | CPUs in the system are full dynticks by default. | |
138 | Note the boot CPU will still be kept outside the range to | |
139 | handle the timekeeping duty. | |
140 | ||
0644ca5c FW |
141 | config NO_HZ |
142 | bool "Old Idle dynticks config" | |
143 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS | |
144 | help | |
145 | This is the old config entry that enables dynticks idle. | |
146 | We keep it around for a little while to enforce backward | |
147 | compatibility with older config files. | |
148 | ||
764e0da1 TG |
149 | config HIGH_RES_TIMERS |
150 | bool "High Resolution Timer Support" | |
151 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS | |
152 | select TICK_ONESHOT | |
153 | help | |
154 | This option enables high resolution timer support. If your | |
155 | hardware is not capable then this option only increases | |
156 | the size of the kernel image. | |
157 | ||
158 | endmenu | |
159 | endif |