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Linux/kernel/time/Kconfig

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Diff markup

Differences between /kernel/time/Kconfig (Version linux-6.11.5) and /kernel/time/Kconfig (Version linux-5.2.21)


  1 # SPDX-License-Identifier: GPL-2.0-only             1 # SPDX-License-Identifier: GPL-2.0-only
  2 #                                                   2 #
  3 # Timer subsystem related configuration option      3 # Timer subsystem related configuration options
  4 #                                                   4 #
  5                                                     5 
  6 # Options selectable by arch Kconfig                6 # Options selectable by arch Kconfig
  7                                                     7 
  8 # Watchdog function for clocksources to detect      8 # Watchdog function for clocksources to detect instabilities
  9 config CLOCKSOURCE_WATCHDOG                         9 config CLOCKSOURCE_WATCHDOG
 10         bool                                       10         bool
 11                                                    11 
 12 # Architecture has extra clocksource data          12 # Architecture has extra clocksource data
 13 config ARCH_CLOCKSOURCE_DATA                       13 config ARCH_CLOCKSOURCE_DATA
 14         bool                                       14         bool
 15                                                    15 
 16 # Architecture has extra clocksource init call     16 # Architecture has extra clocksource init called from registration
 17 config ARCH_CLOCKSOURCE_INIT                       17 config ARCH_CLOCKSOURCE_INIT
 18         bool                                       18         bool
 19                                                    19 
 20 # Clocksources require validation of the clock     20 # Clocksources require validation of the clocksource against the last
 21 # cycle update - x86/TSC misfeature                21 # cycle update - x86/TSC misfeature
 22 config CLOCKSOURCE_VALIDATE_LAST_CYCLE             22 config CLOCKSOURCE_VALIDATE_LAST_CYCLE
 23         bool                                       23         bool
 24                                                    24 
 25 # Timekeeping vsyscall support                     25 # Timekeeping vsyscall support
 26 config GENERIC_TIME_VSYSCALL                       26 config GENERIC_TIME_VSYSCALL
 27         bool                                       27         bool
 28                                                    28 
                                                   >>  29 # Old style timekeeping
                                                   >>  30 config ARCH_USES_GETTIMEOFFSET
                                                   >>  31         bool
                                                   >>  32 
 29 # The generic clock events infrastructure          33 # The generic clock events infrastructure
 30 config GENERIC_CLOCKEVENTS                         34 config GENERIC_CLOCKEVENTS
 31         def_bool !LEGACY_TIMER_TICK            !!  35         bool
 32                                                    36 
 33 # Architecture can handle broadcast in a drive     37 # Architecture can handle broadcast in a driver-agnostic way
 34 config ARCH_HAS_TICK_BROADCAST                     38 config ARCH_HAS_TICK_BROADCAST
 35         bool                                       39         bool
 36                                                    40 
 37 # Clockevents broadcasting infrastructure          41 # Clockevents broadcasting infrastructure
 38 config GENERIC_CLOCKEVENTS_BROADCAST               42 config GENERIC_CLOCKEVENTS_BROADCAST
 39         bool                                       43         bool
 40         depends on GENERIC_CLOCKEVENTS             44         depends on GENERIC_CLOCKEVENTS
 41                                                    45 
 42 # Handle broadcast in default_idle_call()      << 
 43 config GENERIC_CLOCKEVENTS_BROADCAST_IDLE      << 
 44         bool                                   << 
 45         depends on GENERIC_CLOCKEVENTS_BROADCA << 
 46                                                << 
 47 # Automatically adjust the min. reprogramming      46 # Automatically adjust the min. reprogramming time for
 48 # clock event device                               47 # clock event device
 49 config GENERIC_CLOCKEVENTS_MIN_ADJUST              48 config GENERIC_CLOCKEVENTS_MIN_ADJUST
 50         bool                                       49         bool
 51                                                    50 
 52 # Generic update of CMOS clock                     51 # Generic update of CMOS clock
 53 config GENERIC_CMOS_UPDATE                         52 config GENERIC_CMOS_UPDATE
 54         bool                                       53         bool
 55                                                    54 
 56 # Select to handle posix CPU timers from task_ << 
 57 # and not from the timer interrupt context     << 
 58 config HAVE_POSIX_CPU_TIMERS_TASK_WORK         << 
 59         bool                                   << 
 60                                                << 
 61 config POSIX_CPU_TIMERS_TASK_WORK              << 
 62         bool                                   << 
 63         default y if POSIX_TIMERS && HAVE_POSI << 
 64                                                << 
 65 config LEGACY_TIMER_TICK                       << 
 66         bool                                   << 
 67         help                                   << 
 68           The legacy timer tick helper is used << 
 69           lack support for the generic clockev << 
 70           New platforms should use generic clo << 
 71                                                << 
 72 config TIME_KUNIT_TEST                         << 
 73         tristate "KUnit test for kernel/time f << 
 74         depends on KUNIT                       << 
 75         default KUNIT_ALL_TESTS                << 
 76         help                                   << 
 77           Enable this option to test RTC libra << 
 78                                                << 
 79           If unsure, say N.                    << 
 80                                                << 
 81 config CONTEXT_TRACKING                        << 
 82         bool                                   << 
 83                                                << 
 84 config CONTEXT_TRACKING_IDLE                   << 
 85         bool                                   << 
 86         select CONTEXT_TRACKING                << 
 87         help                                   << 
 88           Tracks idle state on behalf of RCU.  << 
 89                                                << 
 90 if GENERIC_CLOCKEVENTS                             55 if GENERIC_CLOCKEVENTS
 91 menu "Timers subsystem"                            56 menu "Timers subsystem"
 92                                                    57 
 93 # Core internal switch. Selected by NO_HZ_COMM     58 # Core internal switch. Selected by NO_HZ_COMMON / HIGH_RES_TIMERS. This is
 94 # only related to the tick functionality. Ones     59 # only related to the tick functionality. Oneshot clockevent devices
 95 # are supported independent of this.               60 # are supported independent of this.
 96 config TICK_ONESHOT                                61 config TICK_ONESHOT
 97         bool                                       62         bool
 98                                                    63 
 99 config NO_HZ_COMMON                                64 config NO_HZ_COMMON
100         bool                                       65         bool
                                                   >>  66         depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS
101         select TICK_ONESHOT                        67         select TICK_ONESHOT
102                                                    68 
103 choice                                             69 choice
104         prompt "Timer tick handling"               70         prompt "Timer tick handling"
105         default NO_HZ_IDLE if NO_HZ                71         default NO_HZ_IDLE if NO_HZ
106                                                    72 
107 config HZ_PERIODIC                                 73 config HZ_PERIODIC
108         bool "Periodic timer ticks (constant r     74         bool "Periodic timer ticks (constant rate, no dynticks)"
109         help                                       75         help
110           This option keeps the tick running p     76           This option keeps the tick running periodically at a constant
111           rate, even when the CPU doesn't need     77           rate, even when the CPU doesn't need it.
112                                                    78 
113 config NO_HZ_IDLE                                  79 config NO_HZ_IDLE
114         bool "Idle dynticks system (tickless i     80         bool "Idle dynticks system (tickless idle)"
                                                   >>  81         depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS
115         select NO_HZ_COMMON                        82         select NO_HZ_COMMON
116         help                                       83         help
117           This option enables a tickless idle      84           This option enables a tickless idle system: timer interrupts
118           will only trigger on an as-needed ba     85           will only trigger on an as-needed basis when the system is idle.
119           This is usually interesting for ener     86           This is usually interesting for energy saving.
120                                                    87 
121           Most of the time you want to say Y h     88           Most of the time you want to say Y here.
122                                                    89 
123 config NO_HZ_FULL                                  90 config NO_HZ_FULL
124         bool "Full dynticks system (tickless)"     91         bool "Full dynticks system (tickless)"
125         # NO_HZ_COMMON dependency                  92         # NO_HZ_COMMON dependency
                                                   >>  93         depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS
126         # We need at least one periodic CPU fo     94         # We need at least one periodic CPU for timekeeping
127         depends on SMP                             95         depends on SMP
128         depends on HAVE_CONTEXT_TRACKING_USER  !!  96         depends on HAVE_CONTEXT_TRACKING
129         # VIRT_CPU_ACCOUNTING_GEN dependency       97         # VIRT_CPU_ACCOUNTING_GEN dependency
130         depends on HAVE_VIRT_CPU_ACCOUNTING_GE     98         depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
131         select NO_HZ_COMMON                        99         select NO_HZ_COMMON
132         select RCU_NOCB_CPU                       100         select RCU_NOCB_CPU
133         select VIRT_CPU_ACCOUNTING_GEN            101         select VIRT_CPU_ACCOUNTING_GEN
134         select IRQ_WORK                           102         select IRQ_WORK
135         select CPU_ISOLATION                      103         select CPU_ISOLATION
136         help                                      104         help
137          Adaptively try to shutdown the tick w    105          Adaptively try to shutdown the tick whenever possible, even when
138          the CPU is running tasks. Typically t    106          the CPU is running tasks. Typically this requires running a single
139          task on the CPU. Chances for running     107          task on the CPU. Chances for running tickless are maximized when
140          the task mostly runs in userspace and    108          the task mostly runs in userspace and has few kernel activity.
141                                                   109 
142          You need to fill up the nohz_full boo    110          You need to fill up the nohz_full boot parameter with the
143          desired range of dynticks CPUs to use !! 111          desired range of dynticks CPUs.
144          the expense of some overhead in user  << 
145          syscalls, exceptions and interrupts.  << 
146                                                   112 
147          By default, without passing the nohz_ !! 113          This is implemented at the expense of some overhead in user <-> kernel
148          like NO_HZ_IDLE.                      !! 114          transitions: syscalls, exceptions and interrupts. Even when it's
                                                   >> 115          dynamically off.
149                                                   116 
150          If you're a distro say Y.             !! 117          Say N.
151                                                   118 
152 endchoice                                         119 endchoice
153                                                   120 
154 config CONTEXT_TRACKING_USER                   !! 121 config CONTEXT_TRACKING
155         bool                                   !! 122        bool
156         depends on HAVE_CONTEXT_TRACKING_USER  !! 123 
157         select CONTEXT_TRACKING                !! 124 config CONTEXT_TRACKING_FORCE
158         help                                   !! 125         bool "Force context tracking"
159           Track transitions between kernel and !! 126         depends on CONTEXT_TRACKING
160           tickless cputime accounting. The for << 
161           tracking to enter/exit RCU extended  << 
162                                                << 
163 config CONTEXT_TRACKING_USER_FORCE             << 
164         bool "Force user context tracking"     << 
165         depends on CONTEXT_TRACKING_USER       << 
166         default y if !NO_HZ_FULL                  127         default y if !NO_HZ_FULL
167         help                                      128         help
168           The major pre-requirement for full d    129           The major pre-requirement for full dynticks to work is to
169           support the user context tracking su !! 130           support the context tracking subsystem. But there are also
170           other dependencies to provide in ord    131           other dependencies to provide in order to make the full
171           dynticks working.                       132           dynticks working.
172                                                   133 
173           This option stands for testing when     134           This option stands for testing when an arch implements the
174           user context tracking backend but do !! 135           context tracking backend but doesn't yet fullfill all the
175           requirements to make the full dyntic    136           requirements to make the full dynticks feature working.
176           Without the full dynticks, there is     137           Without the full dynticks, there is no way to test the support
177           for user context tracking and the su !! 138           for context tracking and the subsystems that rely on it: RCU
178           userspace extended quiescent state a    139           userspace extended quiescent state and tickless cputime
179           accounting. This option copes with t    140           accounting. This option copes with the absence of the full
180           dynticks subsystem by forcing the us !! 141           dynticks subsystem by forcing the context tracking on all
181           CPUs in the system.                     142           CPUs in the system.
182                                                   143 
183           Say Y only if you're working on the     144           Say Y only if you're working on the development of an
184           architecture backend for the user co !! 145           architecture backend for the context tracking.
185                                                   146 
186           Say N otherwise, this option brings     147           Say N otherwise, this option brings an overhead that you
187           don't want in production.               148           don't want in production.
188                                                   149 
189 config NO_HZ                                      150 config NO_HZ
190         bool "Old Idle dynticks config"           151         bool "Old Idle dynticks config"
                                                   >> 152         depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS
191         help                                      153         help
192           This is the old config entry that en    154           This is the old config entry that enables dynticks idle.
193           We keep it around for a little while    155           We keep it around for a little while to enforce backward
194           compatibility with older config file    156           compatibility with older config files.
195                                                   157 
196 config HIGH_RES_TIMERS                            158 config HIGH_RES_TIMERS
197         bool "High Resolution Timer Support"      159         bool "High Resolution Timer Support"
                                                   >> 160         depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS
198         select TICK_ONESHOT                       161         select TICK_ONESHOT
199         help                                      162         help
200           This option enables high resolution     163           This option enables high resolution timer support. If your
201           hardware is not capable then this op    164           hardware is not capable then this option only increases
202           the size of the kernel image.           165           the size of the kernel image.
203                                                << 
204 config CLOCKSOURCE_WATCHDOG_MAX_SKEW_US        << 
205         int "Clocksource watchdog maximum allo << 
206         depends on CLOCKSOURCE_WATCHDOG        << 
207         range 50 1000                          << 
208         default 125                            << 
209         help                                   << 
210           Specify the maximum amount of allowa << 
211           microseconds before reporting the cl << 
212           The default is based on a half-secon << 
213           interval and NTP's maximum frequency << 
214           per million.  If the clocksource is  << 
215           it is good enough for the clocksourc << 
216                                                   166 
217 endmenu                                           167 endmenu
218 endif                                             168 endif
                                                      

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