Commit Graph

5 Commits

Author SHA1 Message Date
Peter Zijlstra
e360adbe29 irq_work: Add generic hardirq context callbacks
Provide a mechanism that allows running code in IRQ context. It is
most useful for NMI code that needs to interact with the rest of the
system -- like wakeup a task to drain buffers.

Perf currently has such a mechanism, so extract that and provide it as
a generic feature, independent of perf so that others may also
benefit.

The IRQ context callback is generated through self-IPIs where
possible, or on architectures like powerpc the decrementer (the
built-in timer facility) is set to generate an interrupt immediately.

Architectures that don't have anything like this get to do with a
callback from the timer tick. These architectures can call
irq_work_run() at the tail of any IRQ handlers that might enqueue such
work (like the perf IRQ handler) to avoid undue latencies in
processing the work.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Kyle McMartin <kyle@mcmartin.ca>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
[ various fixes ]
Signed-off-by: Huang Ying <ying.huang@intel.com>
LKML-Reference: <1287036094.7768.291.camel@yhuang-dev>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-10-18 19:58:50 +02:00
Will Deacon
25d3584797 ARM: 6330/1: perf: reword comments relating to perf_event_do_pending
This is purely a cosmetic change to the ARM perf backend because the current
comments about the relationship between NMIs, interrupt context and
perf_event_do_pending are misleading.

This patch updates the comments so that they reflect what the code
actually does (which is in line with other architectures).

Acked-by: Jamie Iles <jamie.iles@picochip.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-09-01 10:06:08 +01:00
Will Deacon
929f519944 ARM: 6071/1: perf-events: allow modules to query the number of hardware counters
For OProfile to initialise oprofilefs correctly, it needs to know
the number of counters it can represent.

This patch adds a function to the ARM perf-events backend to return
the number of hardware counters available for the current PMU.

Cc: Jamie Iles <jamie.iles@picochip.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-05-17 11:53:58 +01:00
Will Deacon
181193f398 ARM: 6069/1: perf-events: use numeric ID to identify PMU
The ARM perf-events framework provides support for a number of different
PMUs using struct arm_pmu. The char *name field of this struct can be
used to identify the PMU, but this is cumbersome if used outside of perf.

This patch replaces the name string for a PMU with an enum, which holds
a unique ID for the PMU being represented. This ID can be used to index
an array of names within perf, so no functionality is lost. The presence
of the ID field, allows other kernel subsystems [currently oprofile] to
use their own mappings for the PMU name.

Cc: Jean Pihet <jpihet@mvista.com>
Acked-by: Jamie Iles <jamie.iles@picochip.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-05-17 11:53:57 +01:00
Jamie Iles
7ada189f5c ARM: 5900/2: arm: enable support for software perf events
The perf events subsystem allows counting of both hardware and
software events. This patch implements the bare minimum for software
performance events.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jamie Iles <jamie.iles@picochip.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-02-12 17:25:53 +00:00