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* [RFC PATCH 00/15] ARM: perf: support multiple PMUs
@ 2011-08-15 13:55 Mark Rutland
  2011-08-15 13:55 ` [RFC PATCH 01/15] perf: provide PMU when initing events Mark Rutland
                   ` (15 more replies)
  0 siblings, 16 replies; 18+ messages in thread
From: Mark Rutland @ 2011-08-15 13:55 UTC (permalink / raw)
  To: linux-arm-kernel

System (AKA nest or uncore) PMUs exist on devices which are not affine
to a single CPU. They usually cannot be directly associated with
individual tasks and are asynchronous with respect to the current
execution. Examples of devices which could have system PMUs include L2
cache controllers, GPUs and memory buses.

The following patch series refactors the ARM PMU backend, enabling
new PMUs to reuse the existing code. This should allow for system PMUs
to be supported in future. Further work will be required to get perf to
fully understand system PMUs, but this provides something usable.

The framework is intended to be used by system PMUs which hang off core
platform components (e.g. L2 cache, AXI bus). If a device is complex
enough or separate enough from core functionality to have its own
driver, it should implement its own PMU handling using the core perf
API directly.

The first patch ("perf: provide PMU when initing events") is currently
sitting in the tip tree, but as it's required for event initialization
to function (and hence for the PMU to be usable), it's provided here
for convenience.

The series is based on Will Deacon's perf-updates branch at:
	git://linux-arm.org/linux-2.6-wd.git perf-updates

An example driver using the framework (supporting the PMU present in
L220/PL310 level 2 cache controllers) can be found at:
	git://linux-arm.org/linux-2.6-wd.git perf-l2x0-wip

Any comments would be welcome.

Thanks,
Mark.

Mark Rutland (15):
  perf: provide PMU when initing events
  ARM: perf: only register a CPU PMU when present
  ARM: perf: clean up event group validation
  ARM: perf: remove active_mask
  ARM: perf: move active_events into struct arm_pmu
  ARM: perf: move platform device to struct arm_pmu
  ARM: perf: indirect access to cpu_hw_events
  ARM: perf: remove unnecessary armpmu->stop
  ARM: perf: lock PMU registers per-CPU
  ARM: perf: add type field to struct arm_pmu
  ARM: perf: refactor event mapping
  ARM: perf: add support for multiple PMUs
  ARM: perf: remove event limit from pmu_hw_events
  ARM: perf: remove cpu-related misnomers
  ARM: perf: move arm_pmu into <asm/pmu.h>

 arch/arm/include/asm/pmu.h          |   64 +++++++
 arch/arm/kernel/perf_event.c        |  318 +++++++++++++++++------------------
 arch/arm/kernel/perf_event_v6.c     |   73 ++++++---
 arch/arm/kernel/perf_event_v7.c     |   74 +++++---
 arch/arm/kernel/perf_event_xscale.c |   76 +++++----
 kernel/events/core.c                |    4 +-
 6 files changed, 359 insertions(+), 250 deletions(-)

^ permalink raw reply	[flat|nested] 18+ messages in thread
* [RFC PATCH 02/15] ARM: perf: only register a CPU PMU when present
@ 2011-04-27  9:31 Mark Rutland
  0 siblings, 0 replies; 18+ messages in thread
From: Mark Rutland @ 2011-04-27  9:31 UTC (permalink / raw)
  To: linux-arm-kernel

Currently, an "empty" struct pmu is registered as the CPU PMU,
regardless of whether there is a physical PMU. This burdens the
accessor functions with checks to see whether a PMU is actually
present.

This patch changes initialisation to register a PMU only if there is a
supported PMU present, and removes the checks that this change makes
redundant.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
---
 arch/arm/kernel/perf_event.c |   18 ++----------------
 1 files changed, 2 insertions(+), 16 deletions(-)

diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index 5d60c9c..753648c 100644
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -250,9 +250,6 @@ armpmu_stop(struct perf_event *event, int flags)
 {
 	struct hw_perf_event *hwc = &event->hw;
 
-	if (!armpmu)
-		return;
-
 	/*
 	 * ARM pmu always has to update the counter, so ignore
 	 * PERF_EF_UPDATE, see comments in armpmu_start().
@@ -270,9 +267,6 @@ armpmu_start(struct perf_event *event, int flags)
 {
 	struct hw_perf_event *hwc = &event->hw;
 
-	if (!armpmu)
-		return;
-
 	/*
 	 * ARM pmu always has to reprogram the period, so ignore
 	 * PERF_EF_RELOAD, see the comment below.
@@ -567,9 +561,6 @@ static int armpmu_event_init(struct perf_event *event)
 		return -ENOENT;
 	}
 
-	if (!armpmu)
-		return -ENODEV;
-
 	event->destroy = hw_perf_event_destroy;
 
 	if (!atomic_inc_not_zero(&active_events)) {
@@ -599,9 +590,6 @@ static void armpmu_enable(struct pmu *pmu)
 	int idx, enabled = 0;
 	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
 
-	if (!armpmu)
-		return;
-
 	for (idx = 0; idx < armpmu->num_events; ++idx) {
 		struct perf_event *event = cpuc->events[idx];
 
@@ -618,8 +606,7 @@ static void armpmu_enable(struct pmu *pmu)
 
 static void armpmu_disable(struct pmu *pmu)
 {
-	if (armpmu)
-		armpmu->stop();
+	armpmu->stop();
 }
 
 static struct pmu pmu = {
@@ -738,12 +725,11 @@ init_hw_perf_events(void)
 	if (armpmu) {
 		pr_info("enabled with %s PMU driver, %d counters available\n",
 			armpmu->name, armpmu->num_events);
+		perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
 	} else {
 		pr_info("no hardware support available\n");
 	}
 
-	perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
-
 	return 0;
 }
 early_initcall(init_hw_perf_events);
-- 
1.7.0.4

^ permalink raw reply related	[flat|nested] 18+ messages in thread
end of thread, other threads:[~2011-08-17 14:12 UTC | newest]

Thread overview: 18+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2011-08-15 13:55 [RFC PATCH 00/15] ARM: perf: support multiple PMUs Mark Rutland
2011-08-15 13:55 ` [RFC PATCH 01/15] perf: provide PMU when initing events Mark Rutland
2011-08-15 13:55 ` [RFC PATCH 02/15] ARM: perf: only register a CPU PMU when present Mark Rutland
2011-08-15 13:55 ` [RFC PATCH 03/15] ARM: perf: clean up event group validation Mark Rutland
2011-08-15 13:55 ` [RFC PATCH 04/15] ARM: perf: remove active_mask Mark Rutland
2011-08-15 13:55 ` [RFC PATCH 05/15] ARM: perf: move active_events into struct arm_pmu Mark Rutland
2011-08-15 13:55 ` [RFC PATCH 06/15] ARM: perf: move platform device to " Mark Rutland
2011-08-15 13:55 ` [RFC PATCH 07/15] ARM: perf: indirect access to cpu_hw_events Mark Rutland
2011-08-15 13:55 ` [RFC PATCH 08/15] ARM: perf: remove unnecessary armpmu->stop Mark Rutland
2011-08-15 13:55 ` [RFC PATCH 09/15] ARM: perf: lock PMU registers per-CPU Mark Rutland
2011-08-15 13:55 ` [RFC PATCH 10/15] ARM: perf: add type field to struct arm_pmu Mark Rutland
2011-08-15 13:55 ` [RFC PATCH 11/15] ARM: perf: refactor event mapping Mark Rutland
2011-08-15 13:55 ` [RFC PATCH 12/15] ARM: perf: add support for multiple PMUs Mark Rutland
2011-08-15 13:55 ` [RFC PATCH 13/15] ARM: perf: remove event limit from pmu_hw_events Mark Rutland
2011-08-15 13:55 ` [RFC PATCH 14/15] ARM: perf: remove cpu-related misnomers Mark Rutland
2011-08-15 13:55 ` [RFC PATCH 15/15] ARM: perf: move arm_pmu into <asm/pmu.h> Mark Rutland
2011-08-17 14:12 ` [RFC PATCH 00/15] ARM: perf: support multiple PMUs Jamie Iles
  -- strict thread matches above, loose matches on Subject: below --
2011-04-27  9:31 [RFC PATCH 02/15] ARM: perf: only register a CPU PMU when present Mark Rutland

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