[tip:perf/core] perf_events: Optimize perf_event_task_tick()

tip-bot for Peter Zijlstra
2010-02-04T09:57:34Z

Commit-ID: 9717e6cd3db22eade7dbae0fc9235c66325a7132
Gitweb: http://git.kernel.org/tip/9717e6cd3db22eade7dbae0fc9235c66325a7132
Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
AuthorDate: Thu, 28 Jan 2010 13:57:44 +0100
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Thu, 4 Feb 2010 09:59:49 +0100

perf_events: Optimize perf_event_task_tick()

Pretty much all of the calls do perf_disable/perf_enable cycles, pull
that out to cut back on hardware programming.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
kernel/perf_event.c | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 40f8b07..087025f 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -1573,12 +1573,8 @@ static void rotate_ctx(struct perf_event_context *ctx)
raw_spin_lock(&ctx->lock);

/* Rotate the first entry last of non-pinned groups */
- perf_disable();
-
list_rotate_left(&ctx->flexible_groups);

- perf_enable();
-
raw_spin_unlock(&ctx->lock);
}

@@ -1593,6 +1589,8 @@ void perf_event_task_tick(struct task_struct *curr)
cpuctx = &__get_cpu_var(perf_cpu_context);
ctx = curr->perf_event_ctxp;

+ perf_disable();
+
perf_ctx_adjust_freq(&cpuctx->ctx);
if (ctx)
perf_ctx_adjust_freq(ctx);
@@ -1608,6 +1606,8 @@ void perf_event_task_tick(struct task_struct *curr)
cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
if (ctx)
task_ctx_sched_in(curr, EVENT_FLEXIBLE);
+
+ perf_enable();
}

static int event_enable_on_exec(struct perf_event *event,