From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Mon, 21 Nov 2016 21:08:22 +0000 (-0500)
Subject: Performance: add missing unlikely in reserve
X-Git-Url: http://git.efficios.com/?p=deliverable%2Flttng-modules.git;a=commitdiff_plain;h=5ebb028fe8e0cd5f58b5d0368f32e5179dc5db76

Performance: add missing unlikely in reserve

Add missing branch prediction hints within lttng_event_reserve().

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/lttng-ring-buffer-client.h b/lttng-ring-buffer-client.h
index c4b7304f..63f2b4ca 100644
--- a/lttng-ring-buffer-client.h
+++ b/lttng-ring-buffer-client.h
@@ -606,7 +606,7 @@ int lttng_event_reserve(struct lib_ring_buffer_ctx *ctx,
 	int ret, cpu;
 
 	cpu = lib_ring_buffer_get_cpu(&client_config);
-	if (cpu < 0)
+	if (unlikely(cpu < 0))
 		return -EPERM;
 	ctx->cpu = cpu;
 
@@ -624,7 +624,7 @@ int lttng_event_reserve(struct lib_ring_buffer_ctx *ctx,
 	}
 
 	ret = lib_ring_buffer_reserve(&client_config, ctx);
-	if (ret)
+	if (unlikely(ret))
 		goto put;
 	lib_ring_buffer_backend_get_pages(&client_config, ctx,
 			&ctx->backend_pages);