[RFC PATCH 09/15] ARM: perf: lock PMU registers per-CPU
Mark Rutland
mark.rutland at arm.com
Thu Apr 28 05:17:04 EDT 2011
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 at arm.com>
Reviewed-by: Will Deacon <will.deacon at arm.com>
---
arch/arm/kernel/perf_event.c | 17 +++++++++-----
arch/arm/kernel/perf_event_v6.c | 25 +++++++++++++--------
arch/arm/kernel/perf_event_v7.c | 20 ++++++++++-------
arch/arm/kernel/perf_event_xscale.c | 40 +++++++++++++++++++++--------------
4 files changed, 62 insertions(+), 40 deletions(-)
diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index 5ce6c33..9331d57 100644
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -27,12 +27,6 @@
#include <asm/stacktrace.h>
/*
- * Hardware lock to serialize accesses to PMU registers. Needed for the
- * read/modify/write sequences.
- */
-static DEFINE_RAW_SPINLOCK(pmu_lock);
-
-/*
* ARMv6 supports a maximum of 3 events, starting from index 0. If we add
* another platform that supports more, we need to increase this to be the
* largest of all platforms.
@@ -55,6 +49,12 @@ struct cpu_hw_events {
* an event. A 0 means that the counter can be used.
*/
unsigned long used_mask[BITS_TO_LONGS(ARMPMU_MAX_HWEVENTS)];
+
+ /*
+ * Hardware lock to serialize accesses to PMU registers. Needed for the
+ * read/modify/write sequences.
+ */
+ raw_spinlock_t pmu_lock;
};
static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events);
@@ -685,6 +685,11 @@ static struct cpu_hw_events *armpmu_get_cpu_events(void)
static void __init cpu_pmu_init(struct arm_pmu *armpmu)
{
+ int cpu;
+ for_each_possible_cpu(cpu) {
+ struct cpu_hw_events *events = &per_cpu(cpu_hw_events, cpu);
+ raw_spin_lock_init(&events->pmu_lock);
+ }
armpmu->get_hw_events = armpmu_get_cpu_events;
}
diff --git a/arch/arm/kernel/perf_event_v6.c b/arch/arm/kernel/perf_event_v6.c
index 8390128..68cf704 100644
--- a/arch/arm/kernel/perf_event_v6.c
+++ b/arch/arm/kernel/perf_event_v6.c
@@ -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 = {
diff --git a/arch/arm/kernel/perf_event_v7.c b/arch/arm/kernel/perf_event_v7.c
index f4170fc..68ac522 100644
--- a/arch/arm/kernel/perf_event_v7.c
+++ b/arch/arm/kernel/perf_event_v7.c
@@ -936,12 +936,13 @@ static void armv7_pmnc_dump_regs(void)
static void armv7pmu_enable_event(struct hw_perf_event *hwc, int idx)
{
unsigned long flags;
+ struct cpu_hw_events *events = armpmu->get_hw_events();
/*
* Enable counter and interrupt, 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);
/*
* Disable counter
@@ -966,17 +967,18 @@ static void armv7pmu_enable_event(struct hw_perf_event *hwc, int idx)
*/
armv7_pmnc_enable_counter(idx);
- raw_spin_unlock_irqrestore(&pmu_lock, flags);
+ raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
}
static void armv7pmu_disable_event(struct hw_perf_event *hwc, int idx)
{
unsigned long flags;
+ struct cpu_hw_events *events = armpmu->get_hw_events();
/*
* Disable counter and interrupt
*/
- raw_spin_lock_irqsave(&pmu_lock, flags);
+ raw_spin_lock_irqsave(&events->pmu_lock, flags);
/*
* Disable counter
@@ -988,7 +990,7 @@ static void armv7pmu_disable_event(struct hw_perf_event *hwc, int idx)
*/
armv7_pmnc_disable_intens(idx);
- raw_spin_unlock_irqrestore(&pmu_lock, flags);
+ raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
}
static irqreturn_t armv7pmu_handle_irq(int irq_num, void *dev)
@@ -1054,21 +1056,23 @@ static irqreturn_t armv7pmu_handle_irq(int irq_num, void *dev)
static void armv7pmu_start(void)
{
unsigned long flags;
+ struct cpu_hw_events *events = armpmu->get_hw_events();
- raw_spin_lock_irqsave(&pmu_lock, flags);
+ raw_spin_lock_irqsave(&events->pmu_lock, flags);
/* Enable all counters */
armv7_pmnc_write(armv7_pmnc_read() | ARMV7_PMNC_E);
- raw_spin_unlock_irqrestore(&pmu_lock, flags);
+ raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
}
static void armv7pmu_stop(void)
{
unsigned long flags;
+ struct cpu_hw_events *events = armpmu->get_hw_events();
- raw_spin_lock_irqsave(&pmu_lock, flags);
+ raw_spin_lock_irqsave(&events->pmu_lock, flags);
/* Disable all counters */
armv7_pmnc_write(armv7_pmnc_read() & ~ARMV7_PMNC_E);
- raw_spin_unlock_irqrestore(&pmu_lock, flags);
+ raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
}
static int armv7pmu_get_event_idx(struct cpu_hw_events *cpuc,
diff --git a/arch/arm/kernel/perf_event_xscale.c b/arch/arm/kernel/perf_event_xscale.c
index ca89a06..18e4823 100644
--- a/arch/arm/kernel/perf_event_xscale.c
+++ b/arch/arm/kernel/perf_event_xscale.c
@@ -281,6 +281,7 @@ static void
xscale1pmu_enable_event(struct hw_perf_event *hwc, int idx)
{
unsigned long val, mask, evt, flags;
+ struct cpu_hw_events *events = armpmu->get_hw_events();
switch (idx) {
case XSCALE_CYCLE_COUNTER:
@@ -302,18 +303,19 @@ xscale1pmu_enable_event(struct hw_perf_event *hwc, int idx)
return;
}
- raw_spin_lock_irqsave(&pmu_lock, flags);
+ raw_spin_lock_irqsave(&events->pmu_lock, flags);
val = xscale1pmu_read_pmnc();
val &= ~mask;
val |= evt;
xscale1pmu_write_pmnc(val);
- raw_spin_unlock_irqrestore(&pmu_lock, flags);
+ raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
}
static void
xscale1pmu_disable_event(struct hw_perf_event *hwc, int idx)
{
unsigned long val, mask, evt, flags;
+ struct cpu_hw_events *events = armpmu->get_hw_events();
switch (idx) {
case XSCALE_CYCLE_COUNTER:
@@ -333,12 +335,12 @@ xscale1pmu_disable_event(struct hw_perf_event *hwc, int idx)
return;
}
- raw_spin_lock_irqsave(&pmu_lock, flags);
+ raw_spin_lock_irqsave(&events->pmu_lock, flags);
val = xscale1pmu_read_pmnc();
val &= ~mask;
val |= evt;
xscale1pmu_write_pmnc(val);
- raw_spin_unlock_irqrestore(&pmu_lock, flags);
+ raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
}
static int
@@ -365,24 +367,26 @@ static void
xscale1pmu_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 = xscale1pmu_read_pmnc();
val |= XSCALE_PMU_ENABLE;
xscale1pmu_write_pmnc(val);
- raw_spin_unlock_irqrestore(&pmu_lock, flags);
+ raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
}
static void
xscale1pmu_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 = xscale1pmu_read_pmnc();
val &= ~XSCALE_PMU_ENABLE;
xscale1pmu_write_pmnc(val);
- raw_spin_unlock_irqrestore(&pmu_lock, flags);
+ raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
}
static inline u32
@@ -610,6 +614,7 @@ static void
xscale2pmu_enable_event(struct hw_perf_event *hwc, int idx)
{
unsigned long flags, ien, evtsel;
+ struct cpu_hw_events *events = armpmu->get_hw_events();
ien = xscale2pmu_read_int_enable();
evtsel = xscale2pmu_read_event_select();
@@ -643,16 +648,17 @@ xscale2pmu_enable_event(struct hw_perf_event *hwc, int idx)
return;
}
- raw_spin_lock_irqsave(&pmu_lock, flags);
+ raw_spin_lock_irqsave(&events->pmu_lock, flags);
xscale2pmu_write_event_select(evtsel);
xscale2pmu_write_int_enable(ien);
- raw_spin_unlock_irqrestore(&pmu_lock, flags);
+ raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
}
static void
xscale2pmu_disable_event(struct hw_perf_event *hwc, int idx)
{
unsigned long flags, ien, evtsel;
+ struct cpu_hw_events *events = armpmu->get_hw_events();
ien = xscale2pmu_read_int_enable();
evtsel = xscale2pmu_read_event_select();
@@ -686,10 +692,10 @@ xscale2pmu_disable_event(struct hw_perf_event *hwc, int idx)
return;
}
- raw_spin_lock_irqsave(&pmu_lock, flags);
+ raw_spin_lock_irqsave(&events->pmu_lock, flags);
xscale2pmu_write_event_select(evtsel);
xscale2pmu_write_int_enable(ien);
- raw_spin_unlock_irqrestore(&pmu_lock, flags);
+ raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
}
static int
@@ -712,24 +718,26 @@ static void
xscale2pmu_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 = xscale2pmu_read_pmnc() & ~XSCALE_PMU_CNT64;
val |= XSCALE_PMU_ENABLE;
xscale2pmu_write_pmnc(val);
- raw_spin_unlock_irqrestore(&pmu_lock, flags);
+ raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
}
static void
xscale2pmu_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 = xscale2pmu_read_pmnc();
val &= ~XSCALE_PMU_ENABLE;
xscale2pmu_write_pmnc(val);
- raw_spin_unlock_irqrestore(&pmu_lock, flags);
+ raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
}
static inline u32
--
1.7.0.4
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