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/sh/kernel/perf_event.c b/arch/sh/kernel/perf_event.c
index 4bbe190..cf39c48 100644
--- a/arch/sh/kernel/perf_event.c
+++ b/arch/sh/kernel/perf_event.c
@@ -206,26 +206,52 @@
local64_add(delta, &event->count);
}
-static void sh_pmu_disable(struct perf_event *event)
+static void sh_pmu_stop(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
struct hw_perf_event *hwc = &event->hw;
int idx = hwc->idx;
- clear_bit(idx, cpuc->active_mask);
- sh_pmu->disable(hwc, idx);
+ if (!(event->hw.state & PERF_HES_STOPPED)) {
+ sh_pmu->disable(hwc, idx);
+ cpuc->events[idx] = NULL;
+ event->hw.state |= PERF_HES_STOPPED;
+ }
- barrier();
+ if ((flags & PERF_EF_UPDATE) && !(event->hw.state & PERF_HES_UPTODATE)) {
+ sh_perf_event_update(event, &event->hw, idx);
+ event->hw.state |= PERF_HES_UPTODATE;
+ }
+}
- sh_perf_event_update(event, &event->hw, idx);
+static void sh_pmu_start(struct perf_event *event, int flags)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ struct hw_perf_event *hwc = &event->hw;
+ int idx = hwc->idx;
- cpuc->events[idx] = NULL;
- clear_bit(idx, cpuc->used_mask);
+ if (WARN_ON_ONCE(idx == -1))
+ return;
+
+ if (flags & PERF_EF_RELOAD)
+ WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE));
+
+ cpuc->events[idx] = event;
+ event->hw.state = 0;
+ sh_pmu->enable(hwc, idx);
+}
+
+static void sh_pmu_del(struct perf_event *event, int flags)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+
+ sh_pmu_stop(event, PERF_EF_UPDATE);
+ __clear_bit(event->hw.idx, cpuc->used_mask);
perf_event_update_userpage(event);
}
-static int sh_pmu_enable(struct perf_event *event)
+static int sh_pmu_add(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
struct hw_perf_event *hwc = &event->hw;
@@ -234,21 +260,20 @@
perf_pmu_disable(event->pmu);
- if (test_and_set_bit(idx, cpuc->used_mask)) {
+ if (__test_and_set_bit(idx, cpuc->used_mask)) {
idx = find_first_zero_bit(cpuc->used_mask, sh_pmu->num_events);
if (idx == sh_pmu->num_events)
goto out;
- set_bit(idx, cpuc->used_mask);
+ __set_bit(idx, cpuc->used_mask);
hwc->idx = idx;
}
sh_pmu->disable(hwc, idx);
- cpuc->events[idx] = event;
- set_bit(idx, cpuc->active_mask);
-
- sh_pmu->enable(hwc, idx);
+ event->hw.state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
+ if (flags & PERF_EF_START)
+ sh_pmu_start(event, PERF_EF_RELOAD);
perf_event_update_userpage(event);
ret = 0;
@@ -285,7 +310,7 @@
return err;
}
-static void sh_pmu_pmu_enable(struct pmu *pmu)
+static void sh_pmu_enable(struct pmu *pmu)
{
if (!sh_pmu_initialized())
return;
@@ -293,7 +318,7 @@
sh_pmu->enable_all();
}
-static void sh_pmu_pmu_disable(struct pmu *pmu)
+static void sh_pmu_disable(struct pmu *pmu)
{
if (!sh_pmu_initialized())
return;
@@ -302,11 +327,13 @@
}
static struct pmu pmu = {
- .pmu_enable = sh_pmu_pmu_enable,
- .pmu_disable = sh_pmu_pmu_disable,
+ .pmu_enable = sh_pmu_enable,
+ .pmu_disable = sh_pmu_disable,
.event_init = sh_pmu_event_init,
- .enable = sh_pmu_enable,
- .disable = sh_pmu_disable,
+ .add = sh_pmu_add,
+ .del = sh_pmu_del,
+ .start = sh_pmu_start,
+ .stop = sh_pmu_stop,
.read = sh_pmu_read,
};
@@ -334,15 +361,15 @@
return NOTIFY_OK;
}
-int __cpuinit register_sh_pmu(struct sh_pmu *pmu)
+int __cpuinit register_sh_pmu(struct sh_pmu *_pmu)
{
if (sh_pmu)
return -EBUSY;
- sh_pmu = pmu;
+ sh_pmu = _pmu;
- pr_info("Performance Events: %s support registered\n", pmu->name);
+ pr_info("Performance Events: %s support registered\n", _pmu->name);
- WARN_ON(pmu->num_events > MAX_HWEVENTS);
+ WARN_ON(_pmu->num_events > MAX_HWEVENTS);
perf_pmu_register(&pmu);
perf_cpu_notifier(sh_pmu_notifier);