Commit Graph

12 Commits

Author SHA1 Message Date
Will Deacon 5727347180 ARM: 7354/1: perf: limit sample_period to half max_period in non-sampling mode
On ARM, the PMU does not stop counting after an overflow and therefore
IRQ latency affects the new counter value read by the kernel. This is
significant for non-sampling runs where it is possible for the new value
to overtake the previous one, causing the delta to be out by up to
max_period events.

Commit a737823d ("ARM: 6835/1: perf: ensure overflows aren't missed due
to IRQ latency") attempted to fix this problem by allowing interrupt
handlers to pass an overflow flag to the event update function, causing
the overflow calculation to assume that the counter passed through zero
when going from prev to new. Unfortunately, this doesn't work when
overflow occurs on the perf_task_tick path because we have the flag
cleared and end up computing a large negative delta.

This patch removes the overflow flag from armpmu_event_update and
instead limits the sample_period to half of the max_period for
non-sampling profiling runs.

Cc: <stable@vger.kernel.org>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-03-07 09:40:48 +00:00
Ming Lei e0516a64e7 arm: pmu: allow platform specific irq enable/disable handling
This patch introduces .enable_irq and .disable_irq into
struct arm_pmu_platdata, so platform specific irq enablement
can be handled after request_irq, and platform specific irq
disablement can be handled before free_irq.

This patch is for support of  pmu irq routed from CTI on omap4.

Acked-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2011-12-02 15:16:33 +00:00
Will Deacon 14e25c5eeb ARM: PMU: remove pmu_init declaration
pmu_init no longer exists, so don't declare it in asm/pmu.h.

Reported-by: Pawel Moll <Pawel.Moll@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2011-11-16 10:06:57 +00:00
Mark Rutland 0ce47080df ARM: perf: move arm_pmu into <asm/pmu.h>
Currently, struct arm_pmu and related functions are only visible to
{,arch/arm/}/kernel/perf_event.c. This prevents new drivers from using
the framework.

This patch  moves declarations to asm/pmu.h, allowing new PMU drivers
to use the framework.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Jamie Iles <jamie@jamieiles.com>
Reviewed-by: Ashwin Chaugule <ashwinc@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2011-08-31 10:50:13 +01:00
Will Deacon b0e89590f4 ARM: PMU: move CPU PMU platform device handling and init into perf
Once upon a time, OProfile and Perf fought hard over who could play with
the PMU. To stop all hell from breaking loose, pmu.c offered an internal
reserve/release API and took care of parsing PMU platform data passed in
from board support code.

Now that Perf has ingested OProfile, let's move the platform device
handling into the Perf driver and out of the PMU locking code.
Unfortunately, the lock has to remain to prevent Perf being bitten by
out-of-tree modules such as LTTng, which still claim a right to the PMU
when Perf isn't looking.

Acked-by: Jamie Iles <jamie@jamieiles.com>
Reviewed-by: Jean Pihet <j-pihet@ti.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2011-08-31 10:17:59 +01:00
Mark Rutland 7fdd3c4962 ARM: perf: make name of arm_pmu_type consistent
Commit f12482c9 ("ARM: 6974/1: pmu: refactor reservation") changed
{release,reserve}_pmu to take an enum arm_pmu_type as a parameter, but
inconsistently named the parameter `type' or `device'. It would be nice
if these were consistent.

This patch makes use of enum arm_pmu_type consistent, always using
`type'. Related printks are updated, explicitly mentioning `type' also.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2011-08-12 15:40:21 +01:00
Mark Rutland 49bef8331a ARM: perf: fix prototype of release_pmu
Commit  f12482c9 ("ARM: 6974/1: pmu: refactor reservation") changed the
prototype of release_pmu, but missed the stub for when
CONFIG_CPU_HAS_PMU is not selected by the platform.

This patch changes the prototype of the stub, preventing possible build
failures when CONFIG_CPU_HAS_PMU is not selected.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2011-08-12 15:40:21 +01:00
Mark Rutland f12482c939 ARM: 6974/1: pmu: refactor reservation
Currently, PMU platform_device reservation relies on some minor abuse
of the platform_device::id field for determining the type of PMU. This
is problematic for device tree based probing, where the ID cannot be
controlled.

This patch removes reliance on the id field, and depends on each PMU's
platform driver to figure out which type it is. As all PMUs handled by
the current platform_driver name "arm-pmu" are CPU PMUs, this
convention is hardcoded. New PMU types can be supported through the use
of {of,platform}_device_id tables

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Jamie Iles <jamie@jamieiles.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2011-06-29 10:27:08 +01:00
Rabin Vincent 0e25a5c980 ARM: perf_event: allow platform-specific interrupt handler
Allow a platform-specific IRQ handler to be specified via platform data.
This will be used to implement the single-irq workaround for the DB8500.

Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2011-02-17 13:55:45 +01:00
Will Deacon 49c006b937 ARM: 6064/1: pmu: register IRQs at runtime
The current PMU infrastructure for ARM requires that the IRQs for the PMU
device are fixed at compile time and are selected based on the ARCH_ or MACH_ flags. This has the disadvantage of tying the Kernel down to a
particular board as far as profiling is concerned.

This patch replaces the compile-time IRQ registration with a runtime mechanism which allows the IRQs to be registered with the framework as
a platform_device.

A further advantage of this change is that there is scope for registering
different types of performance counters in the future by changing the id
of the platform_device and attaching different resources to it.

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
Will Deacon 28d7f4ec98 ARM: 6063/1: pmu: add enum describing PMU types
This patch adds an enum describing the potential PMU device types in
preparation for PMU device registration via platform devices.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-04-29 18:03:21 +01:00
Jamie Iles 0f4f0672ac ARM: 5899/2: arm: provide a mechanism to reserve performance counters
To add support for perf events and to allow the hardware counters to be
shared with oprofile, we need a way to reserve access to the pmu
(performance monitor unit). Platforms with PMU interrupts should
register the interrupts in arch/arm/kernel/pmu.c

Signed-off-by: Jamie Iles <jamie.iles@picochip.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-02-12 17:23:43 +00:00