perf: Rework the PMU methods
Replace pmu::{enable,disable,start,stop,unthrottle} with
pmu::{add,del,start,stop}, all of which take a flags argument.
The new interface extends the capability to stop a counter while
keeping it scheduled on the PMU. We replace the throttled state with
the generic stopped state.
This also allows us to efficiently stop/start counters over certain
code paths (like IRQ handlers).
It also allows scheduling a counter without it starting, allowing for
a generic frozen state (useful for rotating stopped counters).
The stopped state is implemented in two different ways, depending on
how the architecture implemented the throttled state:
1) We disable the counter:
a) the pmu has per-counter enable bits, we flip that
b) we program a NOP event, preserving the counter state
2) We store the counter state and ignore all read/overflow events
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: paulus <paulus@samba.org>
Cc: stephane eranian <eranian@googlemail.com>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Lin Ming <ming.m.lin@intel.com>
Cc: Yanmin <yanmin_zhang@linux.intel.com>
Cc: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
Cc: David Miller <davem@davemloft.net>
Cc: Michael Cree <mcree@orcon.net.nz>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c
index 37cae67..516be231 100644
--- a/arch/sparc/kernel/perf_event.c
+++ b/arch/sparc/kernel/perf_event.c
@@ -658,13 +658,16 @@
enc = perf_event_get_enc(cpuc->events[i]);
pcr &= ~mask_for_index(idx);
- pcr |= event_encoding(enc, idx);
+ if (hwc->state & PERF_HES_STOPPED)
+ pcr |= nop_for_index(idx);
+ else
+ pcr |= event_encoding(enc, idx);
}
out:
return pcr;
}
-static void sparc_pmu_pmu_enable(struct pmu *pmu)
+static void sparc_pmu_enable(struct pmu *pmu)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
u64 pcr;
@@ -691,7 +694,7 @@
pcr_ops->write(cpuc->pcr);
}
-static void sparc_pmu_pmu_disable(struct pmu *pmu)
+static void sparc_pmu_disable(struct pmu *pmu)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
u64 val;
@@ -710,48 +713,6 @@
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;
- unsigned long flags;
- int i;
-
- local_irq_save(flags);
- perf_pmu_disable(event->pmu);
-
- 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);
-
- perf_event_update_userpage(event);
-
- cpuc->n_events--;
- break;
- }
- }
-
- perf_pmu_enable(event->pmu);
- local_irq_restore(flags);
-}
-
static int active_event_index(struct cpu_hw_events *cpuc,
struct perf_event *event)
{
@@ -765,6 +726,74 @@
return cpuc->current_idx[i];
}
+static void sparc_pmu_start(struct perf_event *event, int flags)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ int idx = active_event_index(cpuc, event);
+
+ if (flags & PERF_EF_RELOAD) {
+ WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE));
+ sparc_perf_event_set_period(event, &event->hw, idx);
+ }
+
+ event->hw.state = 0;
+
+ sparc_pmu_enable_event(cpuc, &event->hw, idx);
+}
+
+static void sparc_pmu_stop(struct perf_event *event, int flags)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ int idx = active_event_index(cpuc, event);
+
+ if (!(event->hw.state & PERF_HES_STOPPED)) {
+ sparc_pmu_disable_event(cpuc, &event->hw, idx);
+ event->hw.state |= PERF_HES_STOPPED;
+ }
+
+ if (!(event->hw.state & PERF_HES_UPTODATE) && (flags & PERF_EF_UPDATE)) {
+ sparc_perf_event_update(event, &event->hw, idx);
+ event->hw.state |= PERF_HES_UPTODATE;
+ }
+}
+
+static void sparc_pmu_del(struct perf_event *event, int _flags)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ unsigned long flags;
+ int i;
+
+ local_irq_save(flags);
+ perf_pmu_disable(event->pmu);
+
+ for (i = 0; i < cpuc->n_events; i++) {
+ if (event == cpuc->event[i]) {
+ /* Absorb the final count and turn off the
+ * event.
+ */
+ sparc_pmu_stop(event, PERF_EF_UPDATE);
+
+ /* 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];
+ }
+
+ perf_event_update_userpage(event);
+
+ cpuc->n_events--;
+ break;
+ }
+ }
+
+ perf_pmu_enable(event->pmu);
+ local_irq_restore(flags);
+}
+
static void sparc_pmu_read(struct perf_event *event)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
@@ -774,15 +803,6 @@
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, idx);
-}
-
static atomic_t active_events = ATOMIC_INIT(0);
static DEFINE_MUTEX(pmc_grab_mutex);
@@ -984,7 +1004,7 @@
return n;
}
-static int sparc_pmu_enable(struct perf_event *event)
+static int sparc_pmu_add(struct perf_event *event, int ef_flags)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
int n0, ret = -EAGAIN;
@@ -1001,6 +1021,10 @@
cpuc->events[n0] = event->hw.event_base;
cpuc->current_idx[n0] = PIC_NO_INDEX;
+ event->hw.state = PERF_HES_UPTODATE;
+ if (!(ef_flags & PERF_EF_START))
+ event->hw.state |= PERF_HES_STOPPED;
+
/*
* If group events scheduling transaction was started,
* skip the schedulability test here, it will be peformed
@@ -1156,13 +1180,14 @@
}
static struct pmu pmu = {
- .pmu_enable = sparc_pmu_pmu_enable,
- .pmu_disable = sparc_pmu_pmu_disable,
+ .pmu_enable = sparc_pmu_enable,
+ .pmu_disable = sparc_pmu_disable,
.event_init = sparc_pmu_event_init,
- .enable = sparc_pmu_enable,
- .disable = sparc_pmu_disable,
+ .add = sparc_pmu_add,
+ .del = sparc_pmu_del,
+ .start = sparc_pmu_start,
+ .stop = sparc_pmu_stop,
.read = sparc_pmu_read,
- .unthrottle = sparc_pmu_unthrottle,
.start_txn = sparc_pmu_start_txn,
.cancel_txn = sparc_pmu_cancel_txn,
.commit_txn = sparc_pmu_commit_txn,
@@ -1243,7 +1268,7 @@
continue;
if (perf_event_overflow(event, 1, &data, regs))
- sparc_pmu_disable_event(cpuc, hwc, idx);
+ sparc_pmu_stop(event, 0);
}
return NOTIFY_STOP;