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The interrupt framework gives a lot of information about each interrupt. It does not keep track of when those interrupts occur though, which is a prerequisite for estimating the next interrupt arrival for power management purposes. Add a mechanism to record the timestamp for each interrupt occurrences in a per-CPU circular buffer to help with the prediction of the next occurrence using a statistical model. Each CPU can store up to IRQ_TIMINGS_SIZE events <irq, timestamp>, the current value of IRQ_TIMINGS_SIZE is 32. Each event is encoded into a single u64, where the high 48 bits are used for the timestamp and the low 16 bits are for the irq number. A static key is introduced so when the irq prediction is switched off at runtime, the overhead is near to zero. It results in most of the code in internals.h for inline reasons and a very few in the new file timings.c. The latter will contain more in the next patch which will provide the statistical model for the next event prediction. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Hannes Reinecke <hare@suse.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: "Rafael J . Wysocki" <rafael@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Link: http://lkml.kernel.org/r/1498227072-5980-1-git-send-email-daniel.lezcano@linaro.org
130 lines
3.0 KiB
Plaintext
130 lines
3.0 KiB
Plaintext
menu "IRQ subsystem"
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# Options selectable by the architecture code
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# Make sparse irq Kconfig switch below available
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config MAY_HAVE_SPARSE_IRQ
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bool
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# Legacy support, required for itanic
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config GENERIC_IRQ_LEGACY
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bool
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# Enable the generic irq autoprobe mechanism
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config GENERIC_IRQ_PROBE
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bool
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# Use the generic /proc/interrupts implementation
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config GENERIC_IRQ_SHOW
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bool
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# Print level/edge extra information
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config GENERIC_IRQ_SHOW_LEVEL
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bool
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# Supports effective affinity mask
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config GENERIC_IRQ_EFFECTIVE_AFF_MASK
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bool
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# Facility to allocate a hardware interrupt. This is legacy support
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# and should not be used in new code. Use irq domains instead.
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config GENERIC_IRQ_LEGACY_ALLOC_HWIRQ
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bool
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# Support for delayed migration from interrupt context
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config GENERIC_PENDING_IRQ
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bool
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# Support for generic irq migrating off cpu before the cpu is offline.
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config GENERIC_IRQ_MIGRATION
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bool
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# Alpha specific irq affinity mechanism
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config AUTO_IRQ_AFFINITY
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bool
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# Tasklet based software resend for pending interrupts on enable_irq()
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config HARDIRQS_SW_RESEND
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bool
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# Preflow handler support for fasteoi (sparc64)
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config IRQ_PREFLOW_FASTEOI
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bool
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# Edge style eoi based handler (cell)
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config IRQ_EDGE_EOI_HANDLER
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bool
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# Generic configurable interrupt chip implementation
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config GENERIC_IRQ_CHIP
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bool
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select IRQ_DOMAIN
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# Generic irq_domain hw <--> linux irq number translation
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config IRQ_DOMAIN
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bool
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# Support for hierarchical irq domains
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config IRQ_DOMAIN_HIERARCHY
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bool
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select IRQ_DOMAIN
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# Generic IRQ IPI support
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config GENERIC_IRQ_IPI
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bool
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# Generic MSI interrupt support
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config GENERIC_MSI_IRQ
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bool
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# Generic MSI hierarchical interrupt domain support
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config GENERIC_MSI_IRQ_DOMAIN
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bool
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select IRQ_DOMAIN_HIERARCHY
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select GENERIC_MSI_IRQ
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config HANDLE_DOMAIN_IRQ
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bool
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config IRQ_TIMINGS
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bool
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config IRQ_DOMAIN_DEBUG
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bool "Expose hardware/virtual IRQ mapping via debugfs"
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depends on IRQ_DOMAIN && DEBUG_FS
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help
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This option will show the mapping relationship between hardware irq
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numbers and Linux irq numbers. The mapping is exposed via debugfs
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in the file "irq_domain_mapping".
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If you don't know what this means you don't need it.
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# Support forced irq threading
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config IRQ_FORCED_THREADING
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bool
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config SPARSE_IRQ
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bool "Support sparse irq numbering" if MAY_HAVE_SPARSE_IRQ
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---help---
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Sparse irq numbering is useful for distro kernels that want
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to define a high CONFIG_NR_CPUS value but still want to have
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low kernel memory footprint on smaller machines.
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( Sparse irqs can also be beneficial on NUMA boxes, as they spread
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out the interrupt descriptors in a more NUMA-friendly way. )
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If you don't know what to do here, say N.
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config GENERIC_IRQ_DEBUGFS
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bool "Expose irq internals in debugfs"
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depends on DEBUG_FS
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default n
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---help---
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Exposes internal state information through debugfs. Mostly for
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developers and debugging of hard to diagnose interrupt problems.
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If you don't know what to do here, say N.
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endmenu
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