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[PATCH] tick-management: dyntick / highres functionality With Ingo Molnar <mingo@elte.hu> Add functions to provide dynamic ticks and high resolution timers. The code which keeps track of jiffies and handles the long idle periods is shared between tick based and high resolution timer based dynticks. The dyntick functionality can be disabled on the kernel commandline. Provide also the infrastructure to support high resolution timers. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-16 10:28:03 +01:00
#
# Timer subsystem related configuration options
#
tick: Document TICK_ONESHOT config option This option has been selected from arch code as it was assumed that it's necessary to support oneshot mode clockevent devices. But it's just a core internal helper to compile tick-oneshot.c if NOHZ or HIG_RES_TIMERS are selected. Reported-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-03-31 12:45:43 +02:00
timers: Provide generic Kconfig switches We really don't want all the arch code defining stuff over and over. [ anna-maria: Added missing GENERIC_CMOS_UPDATE switch ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Anna-Maria Gleixner <anna-maria@glx-um.de> Cc: Paul Mundt <lethal@linux-sh.org> Link: http://lkml.kernel.org/r/1337529587.3208.2.camel@dionysos Acked-by: Sam Ravnborg <sam@ravnborg.org>
2012-05-18 09:59:57 +02:00
# 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
timekeeping: Add CONFIG_HAS_PERSISTENT_CLOCK option Make the persistent clock check a kernel config option, so that some platform can explicitely select it, also make CONFIG_RTC_HCTOSYS and RTC_SYSTOHC depend on its non-existence, which could prevent the persistent clock and RTC code from doing similar thing twice during system's init/suspend/resume phases. If the CONFIG_HAS_PERSISTENT_CLOCK=n, then no change happens for kernel which still does the persistent clock check in timekeeping_init(). Cc: Thomas Gleixner <tglx@linutronix.de> Suggested-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Feng Tang <feng.tang@intel.com> [jstultz: Added dependency for RTC_SYSTOHC as well] Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-01-15 17:09:49 +01:00
# Platforms has a persistent clock
timekeeping: Switch HAS_PERSISTENT_CLOCK to ALWAYS_USE_PERSISTENT_CLOCK Jason pointed out the HAS_PERSISTENT_CLOCK name isn't quite accurate for the config, as some systems may have the persistent_clock in some cases, but not always. So change the config name to the more clear ALWAYS_USE_PERSISTENT_CLOCK. Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-01-26 02:08:12 +01:00
config ALWAYS_USE_PERSISTENT_CLOCK
timekeeping: Add CONFIG_HAS_PERSISTENT_CLOCK option Make the persistent clock check a kernel config option, so that some platform can explicitely select it, also make CONFIG_RTC_HCTOSYS and RTC_SYSTOHC depend on its non-existence, which could prevent the persistent clock and RTC code from doing similar thing twice during system's init/suspend/resume phases. If the CONFIG_HAS_PERSISTENT_CLOCK=n, then no change happens for kernel which still does the persistent clock check in timekeeping_init(). Cc: Thomas Gleixner <tglx@linutronix.de> Suggested-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Feng Tang <feng.tang@intel.com> [jstultz: Added dependency for RTC_SYSTOHC as well] Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-01-15 17:09:49 +01:00
bool
default n
time: Introduce new GENERIC_TIME_VSYSCALL Now that we moved everyone over to GENERIC_TIME_VSYSCALL_OLD, introduce the new declaration and config option for the new update_vsyscall method. Cc: Tony Luck <tony.luck@intel.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul Turner <pjt@google.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-09-12 01:58:13 +02:00
# Timekeeping vsyscall support
config GENERIC_TIME_VSYSCALL
bool
timers: Provide generic Kconfig switches We really don't want all the arch code defining stuff over and over. [ anna-maria: Added missing GENERIC_CMOS_UPDATE switch ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Anna-Maria Gleixner <anna-maria@glx-um.de> Cc: Paul Mundt <lethal@linux-sh.org> Link: http://lkml.kernel.org/r/1337529587.3208.2.camel@dionysos Acked-by: Sam Ravnborg <sam@ravnborg.org>
2012-05-18 09:59:57 +02:00
# Timekeeping vsyscall support
time: Convert CONFIG_GENERIC_TIME_VSYSCALL to CONFIG_GENERIC_TIME_VSYSCALL_OLD To help migrate archtectures over to the new update_vsyscall method, redfine CONFIG_GENERIC_TIME_VSYSCALL as CONFIG_GENERIC_TIME_VSYSCALL_OLD Cc: Tony Luck <tony.luck@intel.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul Turner <pjt@google.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-09-04 21:34:21 +02:00
config GENERIC_TIME_VSYSCALL_OLD
timers: Provide generic Kconfig switches We really don't want all the arch code defining stuff over and over. [ anna-maria: Added missing GENERIC_CMOS_UPDATE switch ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Anna-Maria Gleixner <anna-maria@glx-um.de> Cc: Paul Mundt <lethal@linux-sh.org> Link: http://lkml.kernel.org/r/1337529587.3208.2.camel@dionysos Acked-by: Sam Ravnborg <sam@ravnborg.org>
2012-05-18 09:59:57 +02:00
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
timers: Fixup the Kconfig consolidation fallout Sigh, I missed to check which architecture Kconfig files actually include the core Kconfig file. There are a few which did not. So we broke them. Instead of adding the includes to those, we are better off to move the include to init/Kconfig like we did already with irqs and others. This does not change anything for the architectures using the old style periodic timer mode. It just solves the build wreckage there. For those architectures which use the clock events infrastructure it moves the include of the core Kconfig file to "General setup" which is a way more logical place than having it at random locations specified by the architecture specific Kconfigs. Reported-by: Ingo Molnar <mingo@kernel.org> Cc: Anna-Maria Gleixner <anna-maria@glx-um.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-05-21 23:16:18 +02:00
# Migration helper. Builds, but does not invoke
config GENERIC_CLOCKEVENTS_BUILD
bool
default y
depends on GENERIC_CLOCKEVENTS
clockevents: Add generic timer broadcast function Currently, the timer broadcast mechanism is defined by a function pointer on struct clock_event_device. As the fundamental mechanism for broadcast is architecture-specific, this means that clock_event_device drivers cannot be shared across multiple architectures. This patch adds an (optional) architecture-specific function for timer tick broadcast, allowing drivers which may require broadcast functionality to be shared across multiple architectures. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Cc: linux-arm-kernel@lists.infradead.org Cc: nico@linaro.org Cc: Will.Deacon@arm.com Cc: Marc.Zyngier@arm.com Cc: john.stultz@linaro.org Link: http://lkml.kernel.org/r/1358183124-28461-3-git-send-email-mark.rutland@arm.com Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-01-14 18:05:22 +01:00
# Architecture can handle broadcast in a driver-agnostic way
config ARCH_HAS_TICK_BROADCAST
bool
timers: Provide generic Kconfig switches We really don't want all the arch code defining stuff over and over. [ anna-maria: Added missing GENERIC_CMOS_UPDATE switch ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Anna-Maria Gleixner <anna-maria@glx-um.de> Cc: Paul Mundt <lethal@linux-sh.org> Link: http://lkml.kernel.org/r/1337529587.3208.2.camel@dionysos Acked-by: Sam Ravnborg <sam@ravnborg.org>
2012-05-18 09:59:57 +02:00
# Clockevents broadcasting infrastructure
config GENERIC_CLOCKEVENTS_BROADCAST
bool
depends on GENERIC_CLOCKEVENTS
timers: Fixup the Kconfig consolidation fallout Sigh, I missed to check which architecture Kconfig files actually include the core Kconfig file. There are a few which did not. So we broke them. Instead of adding the includes to those, we are better off to move the include to init/Kconfig like we did already with irqs and others. This does not change anything for the architectures using the old style periodic timer mode. It just solves the build wreckage there. For those architectures which use the clock events infrastructure it moves the include of the core Kconfig file to "General setup" which is a way more logical place than having it at random locations specified by the architecture specific Kconfigs. Reported-by: Ingo Molnar <mingo@kernel.org> Cc: Anna-Maria Gleixner <anna-maria@glx-um.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-05-21 23:16:18 +02:00
# Automatically adjust the min. reprogramming time for
# clock event device
config GENERIC_CLOCKEVENTS_MIN_ADJUST
bool
timers: Provide generic Kconfig switches We really don't want all the arch code defining stuff over and over. [ anna-maria: Added missing GENERIC_CMOS_UPDATE switch ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Anna-Maria Gleixner <anna-maria@glx-um.de> Cc: Paul Mundt <lethal@linux-sh.org> Link: http://lkml.kernel.org/r/1337529587.3208.2.camel@dionysos Acked-by: Sam Ravnborg <sam@ravnborg.org>
2012-05-18 09:59:57 +02:00
# Generic update of CMOS clock
config GENERIC_CMOS_UPDATE
bool
timers: Fixup the Kconfig consolidation fallout Sigh, I missed to check which architecture Kconfig files actually include the core Kconfig file. There are a few which did not. So we broke them. Instead of adding the includes to those, we are better off to move the include to init/Kconfig like we did already with irqs and others. This does not change anything for the architectures using the old style periodic timer mode. It just solves the build wreckage there. For those architectures which use the clock events infrastructure it moves the include of the core Kconfig file to "General setup" which is a way more logical place than having it at random locations specified by the architecture specific Kconfigs. Reported-by: Ingo Molnar <mingo@kernel.org> Cc: Anna-Maria Gleixner <anna-maria@glx-um.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-05-21 23:16:18 +02:00
if GENERIC_CLOCKEVENTS
menu "Timers subsystem"
# Core internal switch. Selected by NO_HZ / 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
bool "Tickless System (Dynamic Ticks)"
depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS
select TICK_ONESHOT
help
This option enables a tickless system: timer interrupts will
only trigger on an as-needed basis both when the system is
busy and when the system is idle.
nohz: Basic full dynticks interface For extreme usecases such as Real Time or HPC, having the ability to shutdown the tick when a single task runs on a CPU is a desired feature: * Reducing the amount of interrupts improves throughput for CPU-bound tasks. The CPU is less distracted from its real job, from an execution time and from the cache point of views. * This also improve latency response as we have less critical sections. Start with introducing a very simple interface to define full dynticks CPU: use a boot time option defined cpumask through the "nohz_extended=" kernel parameter. CPUs that are part of this range will have their tick shutdown whenever possible: provided they run a single task and they don't do kernel activity that require the periodic tick. These details will be later documented in Documentation/* An online CPU must be kept outside this range to handle the timekeeping. Suggested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@linaro.org> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de>
2012-12-18 17:32:19 +01:00
config NO_HZ_EXTENDED
bool "Full dynticks system"
depends on NO_HZ && RCU_USER_QS && VIRT_CPU_ACCOUNTING_GEN && RCU_NOCB_CPU && SMP
select CONTEXT_TRACKING_FORCE
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_extended 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.
timers: Fixup the Kconfig consolidation fallout Sigh, I missed to check which architecture Kconfig files actually include the core Kconfig file. There are a few which did not. So we broke them. Instead of adding the includes to those, we are better off to move the include to init/Kconfig like we did already with irqs and others. This does not change anything for the architectures using the old style periodic timer mode. It just solves the build wreckage there. For those architectures which use the clock events infrastructure it moves the include of the core Kconfig file to "General setup" which is a way more logical place than having it at random locations specified by the architecture specific Kconfigs. Reported-by: Ingo Molnar <mingo@kernel.org> Cc: Anna-Maria Gleixner <anna-maria@glx-um.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-05-21 23:16:18 +02:00
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