From e7bef6b04ca2e8e4cf667c43d7e2ab3034a869d5 Mon Sep 17 00:00:00 2001
From: "David S. Miller" <davem@davemloft.net>
Date: Wed, 20 Jan 2010 02:59:47 -0800
Subject: [PATCH] sparc64: Fully support both performance counters.
Add the rest of the conflict detection and resolution logic necessary
to support more than one counter at a time on sparc64.
The structure and implementation closely mimicks that of powerpc.
Signed-off-by: David S. Miller <davem@davemloft.net>
---
arch/sparc/kernel/perf_event.c | 507 +++++++++++++++++++++++----------
1 file changed, 353 insertions(+), 154 deletions(-)
diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c
index 2386ac6ec956..e856456ec02f 100644
--- a/arch/sparc/kernel/perf_event.c
+++ b/arch/sparc/kernel/perf_event.c
@@ -55,16 +55,49 @@
#define PIC_UPPER_INDEX 0
#define PIC_LOWER_INDEX 1
+#define PIC_NO_INDEX -1
struct cpu_hw_events {
- struct perf_event *events[MAX_HWEVENTS];
- unsigned long used_mask[BITS_TO_LONGS(MAX_HWEVENTS)];
- unsigned long active_mask[BITS_TO_LONGS(MAX_HWEVENTS)];
+ /* Number of events currently scheduled onto this cpu.
+ * This tells how many entries in the arrays below
+ * are valid.
+ */
+ int n_events;
+
+ /* Number of new events added since the last hw_perf_disable().
+ * This works because the perf event layer always adds new
+ * events inside of a perf_{disable,enable}() sequence.
+ */
+ int n_added;
+
+ /* Array of events current scheduled on this cpu. */
+ struct perf_event *event[MAX_HWEVENTS];
+
+ /* Array of encoded longs, specifying the %pcr register
+ * encoding and the mask of PIC counters this even can
+ * be scheduled on. See perf_event_encode() et al.
+ */
+ unsigned long events[MAX_HWEVENTS];
+
+ /* The current counter index assigned to an event. When the
+ * event hasn't been programmed into the cpu yet, this will
+ * hold PIC_NO_INDEX. The event->hw.idx value tells us where
+ * we ought to schedule the event.
+ */
+ int current_idx[MAX_HWEVENTS];
+
+ /* Software copy of %pcr register on this cpu. */
u64 pcr;
+
+ /* Enabled/disable state. */
int enabled;
};
DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = { .enabled = 1, };
+/* An event map describes the characteristics of a performance
+ * counter event. In particular it gives the encoding as well as
+ * a mask telling which counters the event can be measured on.
+ */
struct perf_event_map {
u16 encoding;
u8 pic_mask;
@@ -73,15 +106,20 @@ struct perf_event_map {
#define PIC_LOWER 0x02
};
+/* Encode a perf_event_map entry into a long. */
static unsigned long perf_event_encode(const struct perf_event_map *pmap)
{
return ((unsigned long) pmap->encoding << 16) | pmap->pic_mask;
}
-static void perf_event_decode(unsigned long val, u16 *enc, u8 *msk)
+static u8 perf_event_get_msk(unsigned long val)
+{
+ return val & 0xff;
+}
+
+static u64 perf_event_get_enc(unsigned long val)
{
- *msk = val & 0xff;
- *enc = val >> 16;
+ return val >> 16;
}
#define C(x) PERF_COUNT_HW_CACHE_##x
@@ -495,53 +533,6 @@ static inline void sparc_pmu_disable_event(struct cpu_hw_events *cpuc, struct hw
pcr_ops->write(cpuc->pcr);
}
-void hw_perf_enable(void)
-{
- struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
- u64 val;
- int i;
-
- if (cpuc->enabled)
- return;
-
- cpuc->enabled = 1;
- barrier();
-
- val = cpuc->pcr;
-
- for (i = 0; i < MAX_HWEVENTS; i++) {
- struct perf_event *cp = cpuc->events[i];
- struct hw_perf_event *hwc;
-
- if (!cp)
- continue;
- hwc = &cp->hw;
- val |= hwc->config_base;
- }
-
- cpuc->pcr = val;
-
- pcr_ops->write(cpuc->pcr);
-}
-
-void hw_perf_disable(void)
-{
- struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
- u64 val;
-
- if (!cpuc->enabled)
- return;
-
- cpuc->enabled = 0;
-
- val = cpuc->pcr;
- val &= ~(PCR_UTRACE | PCR_STRACE |
- sparc_pmu->hv_bit | sparc_pmu->irq_bit);
- cpuc->pcr = val;
-
- pcr_ops->write(cpuc->pcr);
-}
-
static u32 read_pmc(int idx)
{
u64 val;
@@ -570,6 +561,30 @@ static void write_pmc(int idx, u64 val)
write_pic(pic);
}
+static u64 sparc_perf_event_update(struct perf_event *event,
+ struct hw_perf_event *hwc, int idx)
+{
+ int shift = 64 - 32;
+ u64 prev_raw_count, new_raw_count;
+ s64 delta;
+
+again:
+ prev_raw_count = atomic64_read(&hwc->prev_count);
+ new_raw_count = read_pmc(idx);
+
+ if (atomic64_cmpxchg(&hwc->prev_count, prev_raw_count,
+ new_raw_count) != prev_raw_count)
+ goto again;
+
+ delta = (new_raw_count << shift) - (prev_raw_count << shift);
+ delta >>= shift;
+
+ atomic64_add(delta, &event->count);
+ atomic64_sub(delta, &hwc->period_left);
+
+ return new_raw_count;
+}
+
static int sparc_perf_event_set_period(struct perf_event *event,
struct hw_perf_event *hwc, int idx)
{
@@ -602,81 +617,166 @@ static int sparc_perf_event_set_period(struct perf_event *event,
return ret;
}
-static int sparc_pmu_enable(struct perf_event *event)
+/* If performance event entries have been added, move existing
+ * events around (if necessary) and then assign new entries to
+ * counters.
+ */
+static u64 maybe_change_configuration(struct cpu_hw_events *cpuc, u64 pcr)
{
- struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
- struct hw_perf_event *hwc = &event->hw;
- int idx = hwc->idx;
+ int i;
- if (test_and_set_bit(idx, cpuc->used_mask))
- return -EAGAIN;
+ if (!cpuc->n_added)
+ goto out;
- sparc_pmu_disable_event(cpuc, hwc, idx);
+ /* Read in the counters which are moving. */
+ for (i = 0; i < cpuc->n_events; i++) {
+ struct perf_event *cp = cpuc->event[i];
- cpuc->events[idx] = event;
- set_bit(idx, cpuc->active_mask);
+ if (cpuc->current_idx[i] != PIC_NO_INDEX &&
+ cpuc->current_idx[i] != cp->hw.idx) {
+ sparc_perf_event_update(cp, &cp->hw,
+ cpuc->current_idx[i]);
+ cpuc->current_idx[i] = PIC_NO_INDEX;
+ }
+ }
- sparc_perf_event_set_period(event, hwc, idx);
- sparc_pmu_enable_event(cpuc, hwc, idx);
- perf_event_update_userpage(event);
- return 0;
+ /* Assign to counters all unassigned events. */
+ for (i = 0; i < cpuc->n_events; i++) {
+ struct perf_event *cp = cpuc->event[i];
+ struct hw_perf_event *hwc = &cp->hw;
+ int idx = hwc->idx;
+ u64 enc;
+
+ if (cpuc->current_idx[i] != PIC_NO_INDEX)
+ continue;
+
+ sparc_perf_event_set_period(cp, hwc, idx);
+ cpuc->current_idx[i] = idx;
+
+ enc = perf_event_get_enc(cpuc->events[i]);
+ pcr |= event_encoding(enc, idx);
+ }
+out:
+ return pcr;
}
-static u64 sparc_perf_event_update(struct perf_event *event,
- struct hw_perf_event *hwc, int idx)
+void hw_perf_enable(void)
{
- int shift = 64 - 32;
- u64 prev_raw_count, new_raw_count;
- s64 delta;
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ u64 pcr;
-again:
- prev_raw_count = atomic64_read(&hwc->prev_count);
- new_raw_count = read_pmc(idx);
+ if (cpuc->enabled)
+ return;
- if (atomic64_cmpxchg(&hwc->prev_count, prev_raw_count,
- new_raw_count) != prev_raw_count)
- goto again;
+ cpuc->enabled = 1;
+ barrier();
- delta = (new_raw_count << shift) - (prev_raw_count << shift);
- delta >>= shift;
+ pcr = cpuc->pcr;
+ if (!cpuc->n_events) {
+ pcr = 0;
+ } else {
+ pcr = maybe_change_configuration(cpuc, pcr);
- atomic64_add(delta, &event->count);
- atomic64_sub(delta, &hwc->period_left);
+ /* We require that all of the events have the same
+ * configuration, so just fetch the settings from the
+ * first entry.
+ */
+ cpuc->pcr = pcr | cpuc->event[0]->hw.config_base;
+ }
- return new_raw_count;
+ pcr_ops->write(cpuc->pcr);
+}
+
+void hw_perf_disable(void)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ u64 val;
+
+ if (!cpuc->enabled)
+ return;
+
+ cpuc->enabled = 0;
+ cpuc->n_added = 0;
+
+ val = cpuc->pcr;
+ val &= ~(PCR_UTRACE | PCR_STRACE |
+ sparc_pmu->hv_bit | sparc_pmu->irq_bit);
+ cpuc->pcr = val;
+
+ pcr_ops->write(cpuc->pcr);
}
static void sparc_pmu_disable(struct perf_event *event)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
struct hw_perf_event *hwc = &event->hw;
- int idx = hwc->idx;
+ unsigned long flags;
+ int i;
- clear_bit(idx, cpuc->active_mask);
- sparc_pmu_disable_event(cpuc, hwc, idx);
+ local_irq_save(flags);
+ perf_disable();
+
+ for (i = 0; i < cpuc->n_events; i++) {
+ if (event == cpuc->event[i]) {
+ int idx = cpuc->current_idx[i];
+
+ /* Shift remaining entries down into
+ * the existing slot.
+ */
+ while (++i < cpuc->n_events) {
+ cpuc->event[i - 1] = cpuc->event[i];
+ cpuc->events[i - 1] = cpuc->events[i];
+ cpuc->current_idx[i - 1] =
+ cpuc->current_idx[i];
+ }
+
+ /* Absorb the final count and turn off the
+ * event.
+ */
+ sparc_pmu_disable_event(cpuc, hwc, idx);
+ barrier();
+ sparc_perf_event_update(event, hwc, idx);
- barrier();
+ perf_event_update_userpage(event);
- sparc_perf_event_update(event, hwc, idx);
- cpuc->events[idx] = NULL;
- clear_bit(idx, cpuc->used_mask);
+ cpuc->n_events--;
+ break;
+ }
+ }
- perf_event_update_userpage(event);
+ perf_enable();
+ local_irq_restore(flags);
+}
+
+static int active_event_index(struct cpu_hw_events *cpuc,
+ struct perf_event *event)
+{
+ int i;
+
+ for (i = 0; i < cpuc->n_events; i++) {
+ if (cpuc->event[i] == event)
+ break;
+ }
+ BUG_ON(i == cpuc->n_events);
+ return cpuc->current_idx[i];
}
static void sparc_pmu_read(struct perf_event *event)
{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ int idx = active_event_index(cpuc, event);
struct hw_perf_event *hwc = &event->hw;
- sparc_perf_event_update(event, hwc, hwc->idx);
+ sparc_perf_event_update(event, hwc, idx);
}
static void sparc_pmu_unthrottle(struct perf_event *event)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ int idx = active_event_index(cpuc, event);
struct hw_perf_event *hwc = &event->hw;
- sparc_pmu_enable_event(cpuc, hwc, hwc->idx);
+ sparc_pmu_enable_event(cpuc, hwc, idx);
}
static atomic_t active_events = ATOMIC_INIT(0);
@@ -754,43 +854,75 @@ static void hw_perf_event_destroy(struct perf_event *event)
/* Make sure all events can be scheduled into the hardware at
* the same time. This is simplified by the fact that we only
* need to support 2 simultaneous HW events.
+ *
+ * As a side effect, the evts[]->hw.idx values will be assigned
+ * on success. These are pending indexes. When the events are
+ * actually programmed into the chip, these values will propagate
+ * to the per-cpu cpuc->current_idx[] slots, see the code in
+ * maybe_change_configuration() for details.
*/
-static int sparc_check_constraints(unsigned long *events, int n_ev)
+static int sparc_check_constraints(struct perf_event **evts,
+ unsigned long *events, int n_ev)
{
- if (n_ev <= perf_max_events) {
- u8 msk1, msk2;
- u16 dummy;
-
- if (n_ev == 1)
- return 0;
- BUG_ON(n_ev != 2);
- perf_event_decode(events[0], &dummy, &msk1);
- perf_event_decode(events[1], &dummy, &msk2);
-
- /* If both events can go on any counter, OK. */
- if (msk1 == (PIC_UPPER | PIC_LOWER) &&
- msk2 == (PIC_UPPER | PIC_LOWER))
- return 0;
-
- /* If one event is limited to a specific counter,
- * and the other can go on both, OK.
- */
- if ((msk1 == PIC_UPPER || msk1 == PIC_LOWER) &&
- msk2 == (PIC_UPPER | PIC_LOWER))
- return 0;
- if ((msk2 == PIC_UPPER || msk2 == PIC_LOWER) &&
- msk1 == (PIC_UPPER | PIC_LOWER))
- return 0;
-
- /* If the events are fixed to different counters, OK. */
- if ((msk1 == PIC_UPPER && msk2 == PIC_LOWER) ||
- (msk1 == PIC_LOWER && msk2 == PIC_UPPER))
- return 0;
-
- /* Otherwise, there is a conflict. */
+ u8 msk0 = 0, msk1 = 0;
+ int idx0 = 0;
+
+ /* This case is possible when we are invoked from
+ * hw_perf_group_sched_in().
+ */
+ if (!n_ev)
+ return 0;
+
+ if (n_ev > perf_max_events)
+ return -1;
+
+ msk0 = perf_event_get_msk(events[0]);
+ if (n_ev == 1) {
+ if (msk0 & PIC_LOWER)
+ idx0 = 1;
+ goto success;
+ }
+ BUG_ON(n_ev != 2);
+ msk1 = perf_event_get_msk(events[1]);
+
+ /* If both events can go on any counter, OK. */
+ if (msk0 == (PIC_UPPER | PIC_LOWER) &&
+ msk1 == (PIC_UPPER | PIC_LOWER))
+ goto success;
+
+ /* If one event is limited to a specific counter,
+ * and the other can go on both, OK.
+ */
+ if ((msk0 == PIC_UPPER || msk0 == PIC_LOWER) &&
+ msk1 == (PIC_UPPER | PIC_LOWER)) {
+ if (msk0 & PIC_LOWER)
+ idx0 = 1;
+ goto success;
}
+ if ((msk1 == PIC_UPPER || msk1 == PIC_LOWER) &&
+ msk0 == (PIC_UPPER | PIC_LOWER)) {
+ if (msk1 & PIC_UPPER)
+ idx0 = 1;
+ goto success;
+ }
+
+ /* If the events are fixed to different counters, OK. */
+ if ((msk0 == PIC_UPPER && msk1 == PIC_LOWER) ||
+ (msk0 == PIC_LOWER && msk1 == PIC_UPPER)) {
+ if (msk0 & PIC_LOWER)
+ idx0 = 1;
+ goto success;
+ }
+
+ /* Otherwise, there is a conflict. */
return -1;
+
+success:
+ evts[0]->hw.idx = idx0;
+ if (n_ev == 2)
+ evts[1]->hw.idx = idx0 ^ 1;
+ return 0;
}
static int check_excludes(struct perf_event **evts, int n_prev, int n_new)
@@ -822,7 +954,8 @@ static int check_excludes(struct perf_event **evts, int n_prev, int n_new)
}
static int collect_events(struct perf_event *group, int max_count,
- struct perf_event *evts[], unsigned long *events)
+ struct perf_event *evts[], unsigned long *events,
+ int *current_idx)
{
struct perf_event *event;
int n = 0;
@@ -831,7 +964,8 @@ static int collect_events(struct perf_event *group, int max_count,
if (n >= max_count)
return -1;
evts[n] = group;
- events[n++] = group->hw.event_base;
+ events[n] = group->hw.event_base;
+ current_idx[n++] = PIC_NO_INDEX;
}
list_for_each_entry(event, &group->sibling_list, group_entry) {
if (!is_software_event(event) &&
@@ -839,20 +973,100 @@ static int collect_events(struct perf_event *group, int max_count,
if (n >= max_count)
return -1;
evts[n] = event;
- events[n++] = event->hw.event_base;
+ events[n] = event->hw.event_base;
+ current_idx[n++] = PIC_NO_INDEX;
}
}
return n;
}
+static void event_sched_in(struct perf_event *event, int cpu)
+{
+ event->state = PERF_EVENT_STATE_ACTIVE;
+ event->oncpu = cpu;
+ event->tstamp_running += event->ctx->time - event->tstamp_stopped;
+ if (is_software_event(event))
+ event->pmu->enable(event);
+}
+
+int hw_perf_group_sched_in(struct perf_event *group_leader,
+ struct perf_cpu_context *cpuctx,
+ struct perf_event_context *ctx, int cpu)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ struct perf_event *sub;
+ int n0, n;
+
+ if (!sparc_pmu)
+ return 0;
+
+ n0 = cpuc->n_events;
+ n = collect_events(group_leader, perf_max_events - n0,
+ &cpuc->event[n0], &cpuc->events[n0],
+ &cpuc->current_idx[n0]);
+ if (n < 0)
+ return -EAGAIN;
+ if (check_excludes(cpuc->event, n0, n))
+ return -EINVAL;
+ if (sparc_check_constraints(cpuc->event, cpuc->events, n + n0))
+ return -EAGAIN;
+ cpuc->n_events = n0 + n;
+ cpuc->n_added += n;
+
+ cpuctx->active_oncpu += n;
+ n = 1;
+ event_sched_in(group_leader, cpu);
+ list_for_each_entry(sub, &group_leader->sibling_list, group_entry) {
+ if (sub->state != PERF_EVENT_STATE_OFF) {
+ event_sched_in(sub, cpu);
+ n++;
+ }
+ }
+ ctx->nr_active += n;
+
+ return 1;
+}
+
+static int sparc_pmu_enable(struct perf_event *event)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ int n0, ret = -EAGAIN;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ perf_disable();
+
+ n0 = cpuc->n_events;
+ if (n0 >= perf_max_events)
+ goto out;
+
+ cpuc->event[n0] = event;
+ cpuc->events[n0] = event->hw.event_base;
+ cpuc->current_idx[n0] = PIC_NO_INDEX;
+
+ if (check_excludes(cpuc->event, n0, 1))
+ goto out;
+ if (sparc_check_constraints(cpuc->event, cpuc->events, n0 + 1))
+ goto out;
+
+ cpuc->n_events++;
+ cpuc->n_added++;
+
+ ret = 0;
+out:
+ perf_enable();
+ local_irq_restore(flags);
+ return ret;
+}
+
static int __hw_perf_event_init(struct perf_event *event)
{
struct perf_event_attr *attr = &event->attr;
struct perf_event *evts[MAX_HWEVENTS];
struct hw_perf_event *hwc = &event->hw;
unsigned long events[MAX_HWEVENTS];
+ int current_idx_dmy[MAX_HWEVENTS];
const struct perf_event_map *pmap;
- u64 enc;
int n;
if (atomic_read(&nmi_active) < 0)
@@ -869,10 +1083,7 @@ static int __hw_perf_event_init(struct perf_event *event)
} else
return -EOPNOTSUPP;
- /* We save the enable bits in the config_base. So to
- * turn off sampling just write 'config', and to enable
- * things write 'config | config_base'.
- */
+ /* We save the enable bits in the config_base. */
hwc->config_base = sparc_pmu->irq_bit;
if (!attr->exclude_user)
hwc->config_base |= PCR_UTRACE;
@@ -883,13 +1094,11 @@ static int __hw_perf_event_init(struct perf_event *event)
hwc->event_base = perf_event_encode(pmap);
- enc = pmap->encoding;
-
n = 0;
if (event->group_leader != event) {
n = collect_events(event->group_leader,
perf_max_events - 1,
- evts, events);
+ evts, events, current_idx_dmy);
if (n < 0)
return -EINVAL;
}
@@ -899,9 +1108,11 @@ static int __hw_perf_event_init(struct perf_event *event)
if (check_excludes(evts, n, 1))
return -EINVAL;
- if (sparc_check_constraints(events, n + 1))
+ if (sparc_check_constraints(evts, events, n + 1))
return -EINVAL;
+ hwc->idx = PIC_NO_INDEX;
+
/* Try to do all error checking before this point, as unwinding
* state after grabbing the PMC is difficult.
*/
@@ -914,15 +1125,6 @@ static int __hw_perf_event_init(struct perf_event *event)
atomic64_set(&hwc->period_left, hwc->sample_period);
}
- if (pmap->pic_mask & PIC_UPPER) {
- hwc->idx = PIC_UPPER_INDEX;
- enc <<= sparc_pmu->upper_shift;
- } else {
- hwc->idx = PIC_LOWER_INDEX;
- enc <<= sparc_pmu->lower_shift;
- }
-
- hwc->config |= enc;
return 0;
}
@@ -972,7 +1174,7 @@ static int __kprobes perf_event_nmi_handler(struct notifier_block *self,
struct perf_sample_data data;
struct cpu_hw_events *cpuc;
struct pt_regs *regs;
- int idx;
+ int i;
if (!atomic_read(&active_events))
return NOTIFY_DONE;
@@ -1001,13 +1203,12 @@ static int __kprobes perf_event_nmi_handler(struct notifier_block *self,
if (sparc_pmu->irq_bit)
pcr_ops->write(cpuc->pcr);
- for (idx = 0; idx < MAX_HWEVENTS; idx++) {
- struct perf_event *event = cpuc->events[idx];
+ for (i = 0; i < cpuc->n_events; i++) {
+ struct perf_event *event = cpuc->event[i];
+ int idx = cpuc->current_idx[i];
struct hw_perf_event *hwc;
u64 val;
- if (!test_bit(idx, cpuc->active_mask))
- continue;
hwc = &event->hw;
val = sparc_perf_event_update(event, hwc, idx);
if (val & (1ULL << 31))
@@ -1059,10 +1260,8 @@ void __init init_hw_perf_events(void)
pr_cont("Supported PMU type is '%s'\n", sparc_pmu_type);
- /* All sparc64 PMUs currently have 2 events. But this simple
- * driver only supports one active event at a time.
- */
- perf_max_events = 1;
+ /* All sparc64 PMUs currently have 2 events. */
+ perf_max_events = 2;
register_die_notifier(&perf_event_nmi_notifier);
}
--
2.20.1