perf: Use jump_labels to optimize the scheduler hooks
Trades a call + conditional + ret for an unconditional jmp.
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20101014203625.501657727@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 97965fa..7f0e7f5 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -487,6 +487,7 @@
#include <linux/ftrace.h>
#include <linux/cpu.h>
#include <linux/irq_work.h>
+#include <linux/jump_label_ref.h>
#include <asm/atomic.h>
#include <asm/local.h>
@@ -895,8 +896,30 @@
extern int perf_num_counters(void);
extern const char *perf_pmu_name(void);
-extern void perf_event_task_sched_in(struct task_struct *task);
-extern void perf_event_task_sched_out(struct task_struct *task, struct task_struct *next);
+extern void __perf_event_task_sched_in(struct task_struct *task);
+extern void __perf_event_task_sched_out(struct task_struct *task, struct task_struct *next);
+
+extern atomic_t perf_task_events;
+
+static inline void perf_event_task_sched_in(struct task_struct *task)
+{
+ JUMP_LABEL(&perf_task_events, have_events);
+ return;
+
+have_events:
+ __perf_event_task_sched_in(task);
+}
+
+static inline
+void perf_event_task_sched_out(struct task_struct *task, struct task_struct *next)
+{
+ JUMP_LABEL(&perf_task_events, have_events);
+ return;
+
+have_events:
+ __perf_event_task_sched_out(task, next);
+}
+
extern int perf_event_init_task(struct task_struct *child);
extern void perf_event_exit_task(struct task_struct *child);
extern void perf_event_free_task(struct task_struct *task);
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 856e20b..f7febb0 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -34,7 +34,7 @@
#include <asm/irq_regs.h>
-static atomic_t nr_events __read_mostly;
+atomic_t perf_task_events __read_mostly;
static atomic_t nr_mmap_events __read_mostly;
static atomic_t nr_comm_events __read_mostly;
static atomic_t nr_task_events __read_mostly;
@@ -1311,8 +1311,8 @@
* accessing the event control register. If a NMI hits, then it will
* not restart the event.
*/
-void perf_event_task_sched_out(struct task_struct *task,
- struct task_struct *next)
+void __perf_event_task_sched_out(struct task_struct *task,
+ struct task_struct *next)
{
int ctxn;
@@ -1340,14 +1340,6 @@
/*
* Called with IRQs disabled
*/
-static void __perf_event_task_sched_out(struct perf_event_context *ctx)
-{
- task_ctx_sched_out(ctx, EVENT_ALL);
-}
-
-/*
- * Called with IRQs disabled
- */
static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
enum event_type_t event_type)
{
@@ -1494,7 +1486,7 @@
* accessing the event control register. If a NMI hits, then it will
* keep the event running.
*/
-void perf_event_task_sched_in(struct task_struct *task)
+void __perf_event_task_sched_in(struct task_struct *task)
{
struct perf_event_context *ctx;
int ctxn;
@@ -2216,7 +2208,8 @@
irq_work_sync(&event->pending);
if (!event->parent) {
- atomic_dec(&nr_events);
+ if (event->attach_state & PERF_ATTACH_TASK)
+ jump_label_dec(&perf_task_events);
if (event->attr.mmap || event->attr.mmap_data)
atomic_dec(&nr_mmap_events);
if (event->attr.comm)
@@ -5354,7 +5347,8 @@
event->pmu = pmu;
if (!event->parent) {
- atomic_inc(&nr_events);
+ if (event->attach_state & PERF_ATTACH_TASK)
+ jump_label_inc(&perf_task_events);
if (event->attr.mmap || event->attr.mmap_data)
atomic_inc(&nr_mmap_events);
if (event->attr.comm)
@@ -5849,7 +5843,7 @@
* our context.
*/
child_ctx = child->perf_event_ctxp[ctxn];
- __perf_event_task_sched_out(child_ctx);
+ task_ctx_sched_out(child_ctx, EVENT_ALL);
/*
* Take the context lock here so that if find_get_context is