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ring-buffer: small optimizations

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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>
This commit is contained in:
Steven Rostedt 2009-05-11 16:08:00 -04:00 • committed by Steven Rostedt
parent be957c447f
commit 0f0c85fc80
1 changed files with 6 additions and 6 deletions
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12
kernel/trace/ring_buffer.c
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@ -1000,7 +1000,7 @@ rb_event_index(struct ring_buffer_event *event)
return (addr & ~PAGE_MASK) - (PAGE_SIZE - BUF_PAGE_SIZE); return (addr & ~PAGE_MASK) - (PAGE_SIZE - BUF_PAGE_SIZE);
} }
static int static inline int
rb_is_commit(struct ring_buffer_per_cpu *cpu_buffer, rb_is_commit(struct ring_buffer_per_cpu *cpu_buffer,
struct ring_buffer_event *event) struct ring_buffer_event *event)
{ {
@ -1423,9 +1423,9 @@ rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer,
* also be made. But only the entry that did the actual * also be made. But only the entry that did the actual
* commit will be something other than zero. * commit will be something other than zero.
*/ */
if (cpu_buffer->tail_page == cpu_buffer->commit_page && if (likely(cpu_buffer->tail_page == cpu_buffer->commit_page &&
rb_page_write(cpu_buffer->tail_page) == rb_page_write(cpu_buffer->tail_page) ==
rb_commit_index(cpu_buffer)) { rb_commit_index(cpu_buffer))) {
delta = ts - cpu_buffer->write_stamp; delta = ts - cpu_buffer->write_stamp;
@ -1436,7 +1436,7 @@ rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer,
if (unlikely(ts < cpu_buffer->write_stamp)) if (unlikely(ts < cpu_buffer->write_stamp))
delta = 0; delta = 0;
if (test_time_stamp(delta)) { else if (unlikely(test_time_stamp(delta))) {
commit = rb_add_time_stamp(cpu_buffer, &ts, &delta); commit = rb_add_time_stamp(cpu_buffer, &ts, &delta);
@ -1470,7 +1470,7 @@ rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer,
* If the timestamp was commited, make the commit our entry * If the timestamp was commited, make the commit our entry
* now so that we will update it when needed. * now so that we will update it when needed.
*/ */
if (commit) if (unlikely(commit))
rb_set_commit_event(cpu_buffer, event); rb_set_commit_event(cpu_buffer, event);
else if (!rb_is_commit(cpu_buffer, event)) else if (!rb_is_commit(cpu_buffer, event))
delta = 0; delta = 0;