blob: f6a792ab498375a764099dd4156d43546dad9255 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
|
#
# Timer subsystem related configuration options
#
# Options selectable by arch Kconfig
# Watchdog function for clocksources to detect instabilities
config CLOCKSOURCE_WATCHDOG
bool
# Architecture has extra clocksource data
config ARCH_CLOCKSOURCE_DATA
bool
# Platforms has a persistent clock
config ALWAYS_USE_PERSISTENT_CLOCK
bool
default n
# Timekeeping vsyscall support
config GENERIC_TIME_VSYSCALL
bool
# Timekeeping vsyscall support
config GENERIC_TIME_VSYSCALL_OLD
bool
# ktime_t scalar 64bit nsec representation
config KTIME_SCALAR
bool
# Old style timekeeping
config ARCH_USES_GETTIMEOFFSET
bool
# The generic clock events infrastructure
config GENERIC_CLOCKEVENTS
bool
# Migration helper. Builds, but does not invoke
config GENERIC_CLOCKEVENTS_BUILD
bool
default y
depends on GENERIC_CLOCKEVENTS
# Architecture can handle broadcast in a driver-agnostic way
config ARCH_HAS_TICK_BROADCAST
bool
# Clockevents broadcasting infrastructure
config GENERIC_CLOCKEVENTS_BROADCAST
bool
depends on GENERIC_CLOCKEVENTS
# Automatically adjust the min. reprogramming time for
# clock event device
config GENERIC_CLOCKEVENTS_MIN_ADJUST
bool
# Generic update of CMOS clock
config GENERIC_CMOS_UPDATE
bool
if GENERIC_CLOCKEVENTS
menu "Timers subsystem"
# Core internal switch. Selected by NO_HZ_COMMON / HIGH_RES_TIMERS. This is
# only related to the tick functionality. Oneshot clockevent devices
# are supported independ of this.
config TICK_ONESHOT
bool
config NO_HZ_COMMON
bool
depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS
select TICK_ONESHOT
choice
prompt "Timer tick handling"
default NO_HZ_IDLE if NO_HZ
config HZ_PERIODIC
bool "Periodic timer ticks (constant rate, no dynticks)"
help
This option keeps the tick running periodically at a constant
rate, even when the CPU doesn't need it.
config NO_HZ_IDLE
bool "Idle dynticks system (tickless idle)"
depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS
select NO_HZ_COMMON
help
This option enables a tickless idle system: timer interrupts
will only trigger on an as-needed basis when the system is idle.
This is usually interesting for energy saving.
Most of the time you want to say Y here.
config NO_HZ_FULL
bool "Full dynticks system (tickless)"
# NO_HZ_COMMON dependency
depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS
# We need at least one periodic CPU for timekeeping
depends on SMP
# RCU_USER_QS dependency
depends on HAVE_CONTEXT_TRACKING
# RCU_NOCB_CPU dependency
depends on TREE_RCU || TREE_PREEMPT_RCU
depends on VIRT_CPU_ACCOUNTING_GEN
select NO_HZ_COMMON
select RCU_USER_QS
select RCU_NOCB_CPU
select CONTEXT_TRACKING_FORCE
select IRQ_WORK
help
Adaptively try to shutdown the tick whenever possible, even when
the CPU is running tasks. Typically this requires running a single
task on the CPU. Chances for running tickless are maximized when
the task mostly runs in userspace and has few kernel activity.
You need to fill up the nohz_full boot parameter with the
desired range of dynticks CPUs.
This is implemented at the expense of some overhead in user <-> kernel
transitions: syscalls, exceptions and interrupts. Even when it's
dynamically off.
Say N.
endchoice
config NO_HZ_FULL_ALL
bool "Full dynticks system on all CPUs by default"
depends on NO_HZ_FULL
help
If the user doesn't pass the nohz_full boot option to
define the range of full dynticks CPUs, consider that all
CPUs in the system are full dynticks by default.
Note the boot CPU will still be kept outside the range to
handle the timekeeping duty.
config NO_HZ
bool "Old Idle dynticks config"
depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS
help
This is the old config entry that enables dynticks idle.
We keep it around for a little while to enforce backward
compatibility with older config files.
config HIGH_RES_TIMERS
bool "High Resolution Timer Support"
depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS
select TICK_ONESHOT
help
This option enables high resolution timer support. If your
hardware is not capable then this option only increases
the size of the kernel image.
endmenu
endif
|
