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Subject[PATCH 4/4] perf_counter: optimize sched in/out of counters
Avoid a function call for !group counters by directly calling the counter
function.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
kernel/perf_counter.c | 25 +++++++++++++++++++------
1 file changed, 19 insertions(+), 6 deletions(-)

Index: linux-2.6/kernel/perf_counter.c
===================================================================
--- linux-2.6.orig/kernel/perf_counter.c
+++ linux-2.6/kernel/perf_counter.c
@@ -826,8 +826,12 @@ void __perf_counter_sched_out(struct per

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_coun
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_coun
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();
--



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