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f21f7b5162
Pull vdso updates from Thomas Gleixner: - Make the handling of compat functions consistent and more robust - Rework the underlying data store so that it is dynamically allocated, which allows the conversion of the last holdout SPARC64 to the generic VDSO implementation - Rework the SPARC64 VDSO to utilize the generic implementation - Mop up the left overs of the non-generic VDSO support in the core code - Expand the VDSO selftest and make them more robust - Allow time namespaces to be enabled independently of the generic VDSO support, which was not possible before due to SPARC64 not using it - Various cleanups and improvements in the related code * tag 'timers-vdso-2026-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (51 commits) timens: Use task_lock guard in timens_get*() timens: Use mutex guard in proc_timens_set_offset() timens: Simplify some calls to put_time_ns() timens: Add a __free() wrapper for put_time_ns() timens: Remove dependency on the vDSO vdso/timens: Move functions to new file selftests: vDSO: vdso_test_correctness: Add a test for time() selftests: vDSO: vdso_test_correctness: Use facilities from parse_vdso.c selftests: vDSO: vdso_test_correctness: Handle different tv_usec types selftests: vDSO: vdso_test_correctness: Drop SYS_getcpu fallbacks selftests: vDSO: vdso_test_gettimeofday: Remove nolibc checks Revert "selftests: vDSO: parse_vdso: Use UAPI headers instead of libc headers" random: vDSO: Remove ifdeffery random: vDSO: Trim vDSO includes vdso/datapage: Trim down unnecessary includes vdso/datapage: Remove inclusion of gettimeofday.h vdso/helpers: Explicitly include vdso/processor.h vdso/gettimeofday: Add explicit includes random: vDSO: Add explicit includes MIPS: vdso: Explicitly include asm/vdso/vdso.h ...
225 lines
6.3 KiB
Plaintext
225 lines
6.3 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0-only
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#
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# Timer subsystem related configuration options
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#
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# Options selectable by arch Kconfig
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# Watchdog function for clocksources to detect instabilities
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config CLOCKSOURCE_WATCHDOG
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bool
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# Architecture has extra clocksource init called from registration
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config ARCH_CLOCKSOURCE_INIT
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bool
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config ARCH_WANTS_CLOCKSOURCE_READ_INLINE
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bool
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# Timekeeping vsyscall support
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config GENERIC_TIME_VSYSCALL
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bool
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# The generic clock events infrastructure
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config GENERIC_CLOCKEVENTS
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def_bool !LEGACY_TIMER_TICK
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# Architecture can handle broadcast in a driver-agnostic way
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config ARCH_HAS_TICK_BROADCAST
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bool
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# Clockevents broadcasting infrastructure
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config GENERIC_CLOCKEVENTS_BROADCAST
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bool
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depends on GENERIC_CLOCKEVENTS
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# Handle broadcast in default_idle_call()
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config GENERIC_CLOCKEVENTS_BROADCAST_IDLE
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bool
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depends on GENERIC_CLOCKEVENTS_BROADCAST
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# Automatically adjust the min. reprogramming time for
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# clock event device
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config GENERIC_CLOCKEVENTS_MIN_ADJUST
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bool
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config GENERIC_CLOCKEVENTS_COUPLED
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bool
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config GENERIC_CLOCKEVENTS_COUPLED_INLINE
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select GENERIC_CLOCKEVENTS_COUPLED
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bool
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# Generic update of CMOS clock
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config GENERIC_CMOS_UPDATE
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bool
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# Deferred rearming of the hrtimer interrupt
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config HRTIMER_REARM_DEFERRED
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def_bool y
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depends on GENERIC_ENTRY && HAVE_GENERIC_TIF_BITS
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depends on HIGH_RES_TIMERS && SCHED_HRTICK
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# Select to handle posix CPU timers from task_work
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# and not from the timer interrupt context
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config HAVE_POSIX_CPU_TIMERS_TASK_WORK
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bool
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config POSIX_CPU_TIMERS_TASK_WORK
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bool
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default y if POSIX_TIMERS && HAVE_POSIX_CPU_TIMERS_TASK_WORK
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config LEGACY_TIMER_TICK
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bool
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help
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The legacy timer tick helper is used by platforms that
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lack support for the generic clockevent framework.
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New platforms should use generic clockevents instead.
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config TIME_KUNIT_TEST
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tristate "KUnit test for kernel/time functions" if !KUNIT_ALL_TESTS
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depends on KUNIT
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default KUNIT_ALL_TESTS
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help
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Enable this option to test RTC library functions.
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If unsure, say N.
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config CONTEXT_TRACKING
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bool
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config CONTEXT_TRACKING_IDLE
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bool
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select CONTEXT_TRACKING
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help
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Tracks idle state on behalf of RCU.
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menu "Timers subsystem"
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if GENERIC_CLOCKEVENTS
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# Core internal switch. Selected by NO_HZ_COMMON / HIGH_RES_TIMERS. This is
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# only related to the tick functionality. Oneshot clockevent devices
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# are supported independent of this.
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config TICK_ONESHOT
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bool
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config NO_HZ_COMMON
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bool
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select TICK_ONESHOT
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choice
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prompt "Timer tick handling"
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default NO_HZ_IDLE if NO_HZ
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config HZ_PERIODIC
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bool "Periodic timer ticks (constant rate, no dynticks)"
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help
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This option keeps the tick running periodically at a constant
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rate, even when the CPU doesn't need it.
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config NO_HZ_IDLE
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bool "Idle dynticks system (tickless idle)"
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select NO_HZ_COMMON
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help
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This option enables a tickless idle system: timer interrupts
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will only trigger on an as-needed basis when the system is idle.
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This is usually interesting for energy saving.
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Most of the time you want to say Y here.
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config NO_HZ_FULL
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bool "Full dynticks system (tickless)"
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# NO_HZ_COMMON dependency
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# We need at least one periodic CPU for timekeeping
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depends on SMP
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depends on HAVE_CONTEXT_TRACKING_USER
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# VIRT_CPU_ACCOUNTING_GEN dependency
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depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
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select NO_HZ_COMMON
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select RCU_NOCB_CPU
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select VIRT_CPU_ACCOUNTING_GEN
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select IRQ_WORK
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select CPU_ISOLATION
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help
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Adaptively try to shutdown the tick whenever possible, even when
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the CPU is running tasks. Typically this requires running a single
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task on the CPU. Chances for running tickless are maximized when
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the task mostly runs in userspace and has few kernel activity.
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You need to fill up the nohz_full boot parameter with the
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desired range of dynticks CPUs to use it. This is implemented at
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the expense of some overhead in user <-> kernel transitions:
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syscalls, exceptions and interrupts.
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By default, without passing the nohz_full parameter, this behaves just
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like NO_HZ_IDLE.
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If you're a distro say Y.
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endchoice
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config CONTEXT_TRACKING_USER
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bool
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depends on HAVE_CONTEXT_TRACKING_USER
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select CONTEXT_TRACKING
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help
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Track transitions between kernel and user on behalf of RCU and
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tickless cputime accounting. The former case relies on context
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tracking to enter/exit RCU extended quiescent states.
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config CONTEXT_TRACKING_USER_FORCE
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bool "Force user context tracking"
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depends on CONTEXT_TRACKING_USER
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default y if !NO_HZ_FULL
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help
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The major pre-requirement for full dynticks to work is to
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support the user context tracking subsystem. But there are also
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other dependencies to provide in order to make the full
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dynticks working.
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This option stands for testing when an arch implements the
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user context tracking backend but doesn't yet fulfill all the
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requirements to make the full dynticks feature working.
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Without the full dynticks, there is no way to test the support
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for user context tracking and the subsystems that rely on it: RCU
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userspace extended quiescent state and tickless cputime
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accounting. This option copes with the absence of the full
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dynticks subsystem by forcing the user context tracking on all
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CPUs in the system.
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Say Y only if you're working on the development of an
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architecture backend for the user context tracking.
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Say N otherwise, this option brings an overhead that you
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don't want in production.
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config NO_HZ
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bool "Old Idle dynticks config"
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help
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This is the old config entry that enables dynticks idle.
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We keep it around for a little while to enforce backward
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compatibility with older config files.
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config HIGH_RES_TIMERS
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bool "High Resolution Timer Support"
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select TICK_ONESHOT
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help
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This option enables high resolution timer support. If your
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hardware is not capable then this option only increases
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the size of the kernel image.
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endif
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config POSIX_AUX_CLOCKS
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bool "Enable auxiliary POSIX clocks"
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depends on POSIX_TIMERS
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help
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Auxiliary POSIX clocks are clocks which can be steered
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independently of the core timekeeper, which controls the
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MONOTONIC, REALTIME, BOOTTIME and TAI clocks. They are useful to
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provide e.g. lockless time accessors to independent PTP clocks
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and other clock domains, which are not correlated to the TAI/NTP
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notion of time.
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endmenu
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