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>

1 files changed, 19 insertions, 6 deletions

diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 473ed2cafbfc..69d4de815963 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();