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 | ||
576094b7 JS |
15 | # Timekeeping vsyscall support |
16 | config GENERIC_TIME_VSYSCALL | |
17 | bool | |
18 | ||
b5e498ad | 19 | # Timekeeping vsyscall support |
70639421 | 20 | config GENERIC_TIME_VSYSCALL_OLD |
b5e498ad TG |
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 | ||
764e0da1 TG |
35 | # Migration helper. Builds, but does not invoke |
36 | config GENERIC_CLOCKEVENTS_BUILD | |
37 | bool | |
38 | default y | |
39 | depends on GENERIC_CLOCKEVENTS | |
40 | ||
12ad1000 MR |
41 | # Architecture can handle broadcast in a driver-agnostic way |
42 | config ARCH_HAS_TICK_BROADCAST | |
43 | bool | |
44 | ||
b5e498ad TG |
45 | # Clockevents broadcasting infrastructure |
46 | config GENERIC_CLOCKEVENTS_BROADCAST | |
47 | bool | |
48 | depends on GENERIC_CLOCKEVENTS | |
49 | ||
764e0da1 TG |
50 | # Automatically adjust the min. reprogramming time for |
51 | # clock event device | |
52 | config GENERIC_CLOCKEVENTS_MIN_ADJUST | |
53 | bool | |
54 | ||
b5e498ad TG |
55 | # Generic update of CMOS clock |
56 | config GENERIC_CMOS_UPDATE | |
57 | bool | |
764e0da1 TG |
58 | |
59 | if GENERIC_CLOCKEVENTS | |
60 | menu "Timers subsystem" | |
61 | ||
3451d024 | 62 | # Core internal switch. Selected by NO_HZ_COMMON / HIGH_RES_TIMERS. This is |
764e0da1 TG |
63 | # only related to the tick functionality. Oneshot clockevent devices |
64 | # are supported independ of this. | |
65 | config TICK_ONESHOT | |
66 | bool | |
67 | ||
3451d024 FW |
68 | config NO_HZ_COMMON |
69 | bool | |
70 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS | |
71 | select TICK_ONESHOT | |
72 | ||
3ca277e4 FW |
73 | choice |
74 | prompt "Timer tick handling" | |
75 | default NO_HZ_IDLE if NO_HZ | |
76 | ||
5b533f4f | 77 | config HZ_PERIODIC |
3ca277e4 FW |
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)" | |
764e0da1 | 85 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS |
3451d024 | 86 | select NO_HZ_COMMON |
764e0da1 | 87 | help |
3ca277e4 FW |
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. | |
764e0da1 | 93 | |
c5bfece2 | 94 | config NO_HZ_FULL |
fae30dd6 | 95 | bool "Full dynticks system (tickless)" |
3451d024 | 96 | # NO_HZ_COMMON dependency |
ab71d36d | 97 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS |
fae30dd6 FW |
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 | |
c58b0df1 FW |
102 | # VIRT_CPU_ACCOUNTING_GEN dependency |
103 | depends on 64BIT | |
3451d024 | 104 | select NO_HZ_COMMON |
ab71d36d FW |
105 | select RCU_USER_QS |
106 | select RCU_NOCB_CPU | |
c58b0df1 | 107 | select VIRT_CPU_ACCOUNTING_GEN |
ab71d36d | 108 | select CONTEXT_TRACKING_FORCE |
76c24fb0 | 109 | select IRQ_WORK |
ab71d36d FW |
110 | help |
111 | Adaptively try to shutdown the tick whenever possible, even when | |
a831881b FW |
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 | ||
c5bfece2 | 116 | You need to fill up the nohz_full boot parameter with the |
a831881b FW |
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 | ||
3ca277e4 FW |
125 | endchoice |
126 | ||
f98823ac FW |
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 | ||
0644ca5c FW |
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 | ||
764e0da1 TG |
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 |