From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Wed, 20 May 2009 10:21:22 +0000 (+0200)
Subject: perf_counter: Optimize sched in/out of counters
X-Git-Tag: v2.6.31-rc1~383^2~250
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=afedadf23a2c90f3ba0d963282cbe6a6be129494;p=profile%2Fivi%2Fkernel-x86-ivi.git

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>
---

diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 473ed2c..69d4de8 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -826,8 +826,12 @@ 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)
-			group_sched_out(counter, cpuctx, ctx);
+		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:
@@ -903,8 +907,12 @@ __perf_counter_sched_in(struct perf_counter_context *ctx,
 		if (counter->cpu != -1 && counter->cpu != cpu)
 			continue;
 
-		if (group_can_go_on(counter, cpuctx, 1))
-			group_sched_in(counter, cpuctx, ctx, cpu);
+		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,
@@ -932,9 +940,14 @@ __perf_counter_sched_in(struct perf_counter_context *ctx,
 		if (counter->cpu != -1 && counter->cpu != cpu)
 			continue;
 
-		if (group_can_go_on(counter, cpuctx, can_add_hw)) {
-			if (group_sched_in(counter, cpuctx, ctx, cpu))
+		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();