perf_counter: generic context switch event

Impact: cleanup

Use the generic software events for context switches.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Orig-LKML-Reference: <20090319194233.283522645@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 4 insertions, 62 deletions

diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 4c4e9eb37ab0..99d5930f0a52 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -710,10 +710,13 @@ void perf_counter_task_sched_out(struct task_struct *task, int cpu)
 {
         struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
         struct perf_counter_context *ctx = &task->perf_counter_ctx;
+        struct pt_regs *regs;
 
         if (likely(!cpuctx->task_ctx))
                 return;
 
+        regs = task_pt_regs(task);
+        perf_swcounter_event(PERF_COUNT_CONTEXT_SWITCHES, 1, 1, regs);
         __perf_counter_sched_out(ctx, cpuctx);
 
         cpuctx->task_ctx = NULL;
@@ -1668,58 +1671,6 @@ static const struct hw_perf_counter_ops perf_ops_task_clock = {
 };
 
 /*
- * Software counter: context switches
- */
-
-static u64 get_context_switches(struct perf_counter *counter)
-{
-        struct task_struct *curr = counter->ctx->task;
-
-        if (curr)
-                return curr->nvcsw + curr->nivcsw;
-        return cpu_nr_switches(smp_processor_id());
-}
-
-static void context_switches_perf_counter_update(struct perf_counter *counter)
-{
-        u64 prev, now;
-        s64 delta;
-
-        prev = atomic64_read(&counter->hw.prev_count);
-        now = get_context_switches(counter);
-
-        atomic64_set(&counter->hw.prev_count, now);
-
-        delta = now - prev;
-
-        atomic64_add(delta, &counter->count);
-}
-
-static void context_switches_perf_counter_read(struct perf_counter *counter)
-{
-        context_switches_perf_counter_update(counter);
-}
-
-static int context_switches_perf_counter_enable(struct perf_counter *counter)
-{
-        if (counter->prev_state <= PERF_COUNTER_STATE_OFF)
-                atomic64_set(&counter->hw.prev_count,
-                             get_context_switches(counter));
-        return 0;
-}
-
-static void context_switches_perf_counter_disable(struct perf_counter *counter)
-{
-        context_switches_perf_counter_update(counter);
-}
-
-static const struct hw_perf_counter_ops perf_ops_context_switches = {
-        .enable         = context_switches_perf_counter_enable,
-        .disable        = context_switches_perf_counter_disable,
-        .read           = context_switches_perf_counter_read,
-};
-
-/*
  * Software counter: cpu migrations
  */
 
@@ -1808,11 +1759,8 @@ sw_perf_counter_init(struct perf_counter *counter)
         case PERF_COUNT_PAGE_FAULTS:
         case PERF_COUNT_PAGE_FAULTS_MIN:
         case PERF_COUNT_PAGE_FAULTS_MAJ:
-                hw_ops = &perf_ops_generic;
-                break;
         case PERF_COUNT_CONTEXT_SWITCHES:
-                if (!counter->hw_event.exclude_kernel)
-                        hw_ops = &perf_ops_context_switches;
+                hw_ops = &perf_ops_generic;
                 break;
         case PERF_COUNT_CPU_MIGRATIONS:
                 if (!counter->hw_event.exclude_kernel)
diff --git a/kernel/sched.c b/kernel/sched.c
index 39e708602169..f76e3c0188a2 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2900,14 +2900,8 @@ unsigned long nr_active(void)
 
 /*
  * Externally visible per-cpu scheduler statistics:
- * cpu_nr_switches(cpu) - number of context switches on that cpu
  * cpu_nr_migrations(cpu) - number of migrations into that cpu
  */
-u64 cpu_nr_switches(int cpu)
-{
-        return cpu_rq(cpu)->nr_switches;
-}
-
 u64 cpu_nr_migrations(int cpu)
 {
         return cpu_rq(cpu)->nr_migrations_in;