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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 TG |
24 | # Old style timekeeping |
25 | config ARCH_USES_GETTIMEOFFSET | |
26 | bool | |
27 | ||
28 | # The generic clock events infrastructure | |
29 | config GENERIC_CLOCKEVENTS | |
30 | bool | |
31 | ||
12ad1000 MR |
32 | # Architecture can handle broadcast in a driver-agnostic way |
33 | config ARCH_HAS_TICK_BROADCAST | |
34 | bool | |
35 | ||
b5e498ad TG |
36 | # Clockevents broadcasting infrastructure |
37 | config GENERIC_CLOCKEVENTS_BROADCAST | |
38 | bool | |
39 | depends on GENERIC_CLOCKEVENTS | |
40 | ||
764e0da1 TG |
41 | # Automatically adjust the min. reprogramming time for |
42 | # clock event device | |
43 | config GENERIC_CLOCKEVENTS_MIN_ADJUST | |
44 | bool | |
45 | ||
b5e498ad TG |
46 | # Generic update of CMOS clock |
47 | config GENERIC_CMOS_UPDATE | |
48 | bool | |
764e0da1 TG |
49 | |
50 | if GENERIC_CLOCKEVENTS | |
51 | menu "Timers subsystem" | |
52 | ||
3451d024 | 53 | # Core internal switch. Selected by NO_HZ_COMMON / HIGH_RES_TIMERS. This is |
764e0da1 | 54 | # only related to the tick functionality. Oneshot clockevent devices |
6082a6e4 | 55 | # are supported independent of this. |
764e0da1 TG |
56 | config TICK_ONESHOT |
57 | bool | |
58 | ||
3451d024 FW |
59 | config NO_HZ_COMMON |
60 | bool | |
61 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS | |
62 | select TICK_ONESHOT | |
63 | ||
3ca277e4 FW |
64 | choice |
65 | prompt "Timer tick handling" | |
66 | default NO_HZ_IDLE if NO_HZ | |
67 | ||
5b533f4f | 68 | config HZ_PERIODIC |
3ca277e4 FW |
69 | bool "Periodic timer ticks (constant rate, no dynticks)" |
70 | help | |
71 | This option keeps the tick running periodically at a constant | |
72 | rate, even when the CPU doesn't need it. | |
73 | ||
74 | config NO_HZ_IDLE | |
75 | bool "Idle dynticks system (tickless idle)" | |
764e0da1 | 76 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS |
3451d024 | 77 | select NO_HZ_COMMON |
764e0da1 | 78 | help |
3ca277e4 FW |
79 | This option enables a tickless idle system: timer interrupts |
80 | will only trigger on an as-needed basis when the system is idle. | |
81 | This is usually interesting for energy saving. | |
82 | ||
83 | Most of the time you want to say Y here. | |
764e0da1 | 84 | |
c5bfece2 | 85 | config NO_HZ_FULL |
fae30dd6 | 86 | bool "Full dynticks system (tickless)" |
3451d024 | 87 | # NO_HZ_COMMON dependency |
ab71d36d | 88 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS |
fae30dd6 FW |
89 | # We need at least one periodic CPU for timekeeping |
90 | depends on SMP | |
fae30dd6 | 91 | depends on HAVE_CONTEXT_TRACKING |
c58b0df1 | 92 | # VIRT_CPU_ACCOUNTING_GEN dependency |
554b0004 | 93 | depends on HAVE_VIRT_CPU_ACCOUNTING_GEN |
3451d024 | 94 | select NO_HZ_COMMON |
ab71d36d | 95 | select RCU_NOCB_CPU |
c58b0df1 | 96 | select VIRT_CPU_ACCOUNTING_GEN |
76c24fb0 | 97 | select IRQ_WORK |
bf29cb23 | 98 | select CPU_ISOLATION |
ab71d36d FW |
99 | help |
100 | Adaptively try to shutdown the tick whenever possible, even when | |
a831881b FW |
101 | the CPU is running tasks. Typically this requires running a single |
102 | task on the CPU. Chances for running tickless are maximized when | |
103 | the task mostly runs in userspace and has few kernel activity. | |
104 | ||
c5bfece2 | 105 | You need to fill up the nohz_full boot parameter with the |
a831881b FW |
106 | desired range of dynticks CPUs. |
107 | ||
108 | This is implemented at the expense of some overhead in user <-> kernel | |
109 | transitions: syscalls, exceptions and interrupts. Even when it's | |
110 | dynamically off. | |
111 | ||
112 | Say N. | |
113 | ||
3ca277e4 FW |
114 | endchoice |
115 | ||
f98823ac | 116 | config NO_HZ_FULL_ALL |
f96a34e2 | 117 | bool "Full dynticks system on all CPUs by default (except CPU 0)" |
f98823ac FW |
118 | depends on NO_HZ_FULL |
119 | help | |
120 | If the user doesn't pass the nohz_full boot option to | |
121 | define the range of full dynticks CPUs, consider that all | |
122 | CPUs in the system are full dynticks by default. | |
123 | Note the boot CPU will still be kept outside the range to | |
124 | handle the timekeeping duty. | |
125 | ||
0644ca5c FW |
126 | config NO_HZ |
127 | bool "Old Idle dynticks config" | |
128 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS | |
129 | help | |
130 | This is the old config entry that enables dynticks idle. | |
131 | We keep it around for a little while to enforce backward | |
132 | compatibility with older config files. | |
133 | ||
764e0da1 TG |
134 | config HIGH_RES_TIMERS |
135 | bool "High Resolution Timer Support" | |
136 | depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS | |
137 | select TICK_ONESHOT | |
138 | help | |
139 | This option enables high resolution timer support. If your | |
140 | hardware is not capable then this option only increases | |
141 | the size of the kernel image. | |
142 | ||
143 | endmenu | |
144 | endif |