ring-buffer: small optimizations
Doing some small changes in the fast path of the ring buffer recording
saves over 3% in the ring-buffer-benchmark test.
[ Impact: a little faster ring buffer recording ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 493cba4..f452de2 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1000,7 +1000,7 @@
return (addr & ~PAGE_MASK) - (PAGE_SIZE - BUF_PAGE_SIZE);
}
-static int
+static inline int
rb_is_commit(struct ring_buffer_per_cpu *cpu_buffer,
struct ring_buffer_event *event)
{
@@ -1423,9 +1423,9 @@
* also be made. But only the entry that did the actual
* commit will be something other than zero.
*/
- if (cpu_buffer->tail_page == cpu_buffer->commit_page &&
- rb_page_write(cpu_buffer->tail_page) ==
- rb_commit_index(cpu_buffer)) {
+ if (likely(cpu_buffer->tail_page == cpu_buffer->commit_page &&
+ rb_page_write(cpu_buffer->tail_page) ==
+ rb_commit_index(cpu_buffer))) {
delta = ts - cpu_buffer->write_stamp;
@@ -1436,7 +1436,7 @@
if (unlikely(ts < cpu_buffer->write_stamp))
delta = 0;
- if (test_time_stamp(delta)) {
+ else if (unlikely(test_time_stamp(delta))) {
commit = rb_add_time_stamp(cpu_buffer, &ts, &delta);
@@ -1470,7 +1470,7 @@
* If the timestamp was commited, make the commit our entry
* now so that we will update it when needed.
*/
- if (commit)
+ if (unlikely(commit))
rb_set_commit_event(cpu_buffer, event);
else if (!rb_is_commit(cpu_buffer, event))
delta = 0;
