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/alpha/kernel/perf_event.c b/arch/alpha/kernel/perf_event.c
index 3e26073..380ef02 100644
--- a/arch/alpha/kernel/perf_event.c
+++ b/arch/alpha/kernel/perf_event.c
@@ -307,7 +307,7 @@
new_raw_count) != prev_raw_count)
goto again;
- delta = (new_raw_count - (prev_raw_count & alpha_pmu->pmc_count_mask[idx])) + ovf;
+ delta = (new_raw_count - (prev_raw_count & alpha_pmu->pmc_count_mask[idx])) + ovf;
/* It is possible on very rare occasions that the PMC has overflowed
* but the interrupt is yet to come. Detect and fix this situation.
@@ -402,14 +402,13 @@
struct hw_perf_event *hwc = &pe->hw;
int idx = hwc->idx;
- if (cpuc->current_idx[j] != PMC_NO_INDEX) {
- cpuc->idx_mask |= (1<<cpuc->current_idx[j]);
- continue;
+ if (cpuc->current_idx[j] == PMC_NO_INDEX) {
+ alpha_perf_event_set_period(pe, hwc, idx);
+ cpuc->current_idx[j] = idx;
}
- alpha_perf_event_set_period(pe, hwc, idx);
- cpuc->current_idx[j] = idx;
- cpuc->idx_mask |= (1<<cpuc->current_idx[j]);
+ if (!(hwc->state & PERF_HES_STOPPED))
+ cpuc->idx_mask |= (1<<cpuc->current_idx[j]);
}
cpuc->config = cpuc->event[0]->hw.config_base;
}
@@ -420,7 +419,7 @@
* - this function is called from outside this module via the pmu struct
* returned from perf event initialisation.
*/
-static int alpha_pmu_enable(struct perf_event *event)
+static int alpha_pmu_add(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
int n0;
@@ -455,6 +454,10 @@
}
}
+ hwc->state = PERF_HES_UPTODATE;
+ if (!(flags & PERF_EF_START))
+ hwc->state |= PERF_HES_STOPPED;
+
local_irq_restore(flags);
perf_pmu_enable(event->pmu);
@@ -467,7 +470,7 @@
* - this function is called from outside this module via the pmu struct
* returned from perf event initialisation.
*/
-static void alpha_pmu_disable(struct perf_event *event)
+static void alpha_pmu_del(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
struct hw_perf_event *hwc = &event->hw;
@@ -514,13 +517,44 @@
}
-static void alpha_pmu_unthrottle(struct perf_event *event)
+static void alpha_pmu_stop(struct perf_event *event, int flags)
{
struct hw_perf_event *hwc = &event->hw;
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ if (!(hwc->state & PERF_HES_STOPPED)) {
+ cpuc->idx_mask &= !(1UL<<hwc->idx);
+ hwc->state |= PERF_HES_STOPPED;
+ }
+
+ if ((flags & PERF_EF_UPDATE) && !(hwc->state & PERF_HES_UPTODATE)) {
+ alpha_perf_event_update(event, hwc, hwc->idx, 0);
+ hwc->state |= PERF_HES_UPTODATE;
+ }
+
+ if (cpuc->enabled)
+ wrperfmon(PERFMON_CMD_ENABLE, (1UL<<hwc->idx));
+}
+
+
+static void alpha_pmu_start(struct perf_event *event, int flags)
+{
+ struct hw_perf_event *hwc = &event->hw;
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+
+ if (WARN_ON_ONCE(!(hwc->state & PERF_HES_STOPPED)))
+ return;
+
+ if (flags & PERF_EF_RELOAD) {
+ WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
+ alpha_perf_event_set_period(event, hwc, hwc->idx);
+ }
+
+ hwc->state = 0;
+
cpuc->idx_mask |= 1UL<<hwc->idx;
- wrperfmon(PERFMON_CMD_ENABLE, (1UL<<hwc->idx));
+ if (cpuc->enabled)
+ wrperfmon(PERFMON_CMD_ENABLE, (1UL<<hwc->idx));
}
@@ -671,7 +705,7 @@
/*
* Main entry point - enable HW performance counters.
*/
-static void alpha_pmu_pmu_enable(struct pmu *pmu)
+static void alpha_pmu_enable(struct pmu *pmu)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
@@ -697,7 +731,7 @@
* Main entry point - disable HW performance counters.
*/
-static void alpha_pmu_pmu_disable(struct pmu *pmu)
+static void alpha_pmu_disable(struct pmu *pmu)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
@@ -711,13 +745,14 @@
}
static struct pmu pmu = {
- .pmu_enable = alpha_pmu_pmu_enable,
- .pmu_disable = alpha_pmu_pmu_disable,
+ .pmu_enable = alpha_pmu_enable,
+ .pmu_disable = alpha_pmu_disable,
.event_init = alpha_pmu_event_init,
- .enable = alpha_pmu_enable,
- .disable = alpha_pmu_disable,
+ .add = alpha_pmu_add,
+ .del = alpha_pmu_del,
+ .start = alpha_pmu_start,
+ .stop = alpha_pmu_stop,
.read = alpha_pmu_read,
- .unthrottle = alpha_pmu_unthrottle,
};