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ARM: perf: lock PMU registers per-CPU

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Currently, a single lock serialises access to CPU PMU registers. This
global locking is unnecessary as PMU registers are local to the CPU
they monitor.

This patch replaces the global lock with a per-CPU lock. As the lock is
in struct cpu_hw_events, PMUs providing a single cpu_hw_events instance
can be locked globally.

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>
This commit is contained in:
Mark Rutland
2011-04-28 10:17:04 +01:00
committed by Will Deacon
parent 1b69beb768
commit 0f78d2d5cc
4 changed files with 62 additions and 40 deletions
Download Patch File Download Diff File Expand all files Collapse all files

25
arch/arm/kernel/perf_event_v6.c
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@@ -433,6 +433,7 @@ armv6pmu_enable_event(struct hw_perf_event *hwc,
int idx)
{
unsigned long val, mask, evt, flags;
struct cpu_hw_events *events = armpmu->get_hw_events();
if (ARMV6_CYCLE_COUNTER == idx) {
mask = 0;
@@ -454,12 +455,12 @@ armv6pmu_enable_event(struct hw_perf_event *hwc,
* Mask out the current event and set the counter to count the event
* that we're interested in.
*/
raw_spin_lock_irqsave(&pmu_lock, flags);
raw_spin_lock_irqsave(&events->pmu_lock, flags);
val = armv6_pmcr_read();
val &= ~mask;
val |= evt;
armv6_pmcr_write(val);
raw_spin_unlock_irqrestore(&pmu_lock, flags);
raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
}
static int counter_is_active(unsigned long pmcr, int idx)
@@ -544,24 +545,26 @@ static void
armv6pmu_start(void)
{
unsigned long flags, val;
struct cpu_hw_events *events = armpmu->get_hw_events();
raw_spin_lock_irqsave(&pmu_lock, flags);
raw_spin_lock_irqsave(&events->pmu_lock, flags);
val = armv6_pmcr_read();
val |= ARMV6_PMCR_ENABLE;
armv6_pmcr_write(val);
raw_spin_unlock_irqrestore(&pmu_lock, flags);
raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
}
static void
armv6pmu_stop(void)
{
unsigned long flags, val;
struct cpu_hw_events *events = armpmu->get_hw_events();
raw_spin_lock_irqsave(&pmu_lock, flags);
raw_spin_lock_irqsave(&events->pmu_lock, flags);
val = armv6_pmcr_read();
val &= ~ARMV6_PMCR_ENABLE;
armv6_pmcr_write(val);
raw_spin_unlock_irqrestore(&pmu_lock, flags);
raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
}
static int
@@ -595,6 +598,7 @@ armv6pmu_disable_event(struct hw_perf_event *hwc,
int idx)
{
unsigned long val, mask, evt, flags;
struct cpu_hw_events *events = armpmu->get_hw_events();
if (ARMV6_CYCLE_COUNTER == idx) {
mask = ARMV6_PMCR_CCOUNT_IEN;
@@ -615,12 +619,12 @@ armv6pmu_disable_event(struct hw_perf_event *hwc,
* of ETM bus signal assertion cycles. The external reporting should
* be disabled and so this should never increment.
*/
raw_spin_lock_irqsave(&pmu_lock, flags);
raw_spin_lock_irqsave(&events->pmu_lock, flags);
val = armv6_pmcr_read();
val &= ~mask;
val |= evt;
armv6_pmcr_write(val);
raw_spin_unlock_irqrestore(&pmu_lock, flags);
raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
}
static void
@@ -628,6 +632,7 @@ armv6mpcore_pmu_disable_event(struct hw_perf_event *hwc,
int idx)
{
unsigned long val, mask, flags, evt = 0;
struct cpu_hw_events *events = armpmu->get_hw_events();
if (ARMV6_CYCLE_COUNTER == idx) {
mask = ARMV6_PMCR_CCOUNT_IEN;
@@ -644,12 +649,12 @@ armv6mpcore_pmu_disable_event(struct hw_perf_event *hwc,
* Unlike UP ARMv6, we don't have a way of stopping the counters. We
* simply disable the interrupt reporting.
*/
raw_spin_lock_irqsave(&pmu_lock, flags);
raw_spin_lock_irqsave(&events->pmu_lock, flags);
val = armv6_pmcr_read();
val &= ~mask;
val |= evt;
armv6_pmcr_write(val);
raw_spin_unlock_irqrestore(&pmu_lock, flags);
raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
}
static struct arm_pmu armv6pmu = {