perf_counter: Optimize sched in/out of counters

Avoid a function call for !group counters by directly calling the counter
function.

[ Impact: micro-optimize the code ]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
LKML-Reference: <20090520102553.511933670@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/perf_counter.c

@@ -826,9 +826,13 @@ void __perf_counter_sched_out(struct perf_counter_context *ctx,
 
 	perf_disable();
 	if (ctx->nr_active) {
-		list_for_each_entry(counter, &ctx->counter_list, list_entry)
+		list_for_each_entry(counter, &ctx->counter_list, list_entry) {
+			if (counter != counter->group_leader)
+				counter_sched_out(counter, cpuctx, ctx);
+			else
 				group_sched_out(counter, cpuctx, ctx);
 		}
+	}
 	perf_enable();
  out:
 	spin_unlock(&ctx->lock);
@@ -903,8 +907,12 @@ __perf_counter_sched_in(struct perf_counter_context *ctx,
 		if (counter->cpu != -1 && counter->cpu != cpu)
 			continue;
 
+		if (counter != counter->group_leader)
+			counter_sched_in(counter, cpuctx, ctx, cpu);
+		else {
 			if (group_can_go_on(counter, cpuctx, 1))
 				group_sched_in(counter, cpuctx, ctx, cpu);
+		}
 
 		/*
 		 * If this pinned group hasn't been scheduled,
@@ -932,11 +940,16 @@ __perf_counter_sched_in(struct perf_counter_context *ctx,
 		if (counter->cpu != -1 && counter->cpu != cpu)
 			continue;
 
+		if (counter != counter->group_leader) {
+			if (counter_sched_in(counter, cpuctx, ctx, cpu))
+				can_add_hw = 0;
+		} else {
 			if (group_can_go_on(counter, cpuctx, can_add_hw)) {
 				if (group_sched_in(counter, cpuctx, ctx, cpu))
 					can_add_hw = 0;
 			}
 		}
+	}
 	perf_enable();
  out:
 	spin_unlock(&ctx->lock);