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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-4.20.17)


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

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