Performance: disable event counting by default

[lttng-modules.git] / lib / ringbuffer / ring_buffer_frontend.c

diff --git a/lib/ringbuffer/ring_buffer_frontend.c b/lib/ringbuffer/ring_buffer_frontend.c
index c5123a6415e39afc75cc55b8208b9b6924fbf975..9d13d2920420ee6c525d1e22ac0558dc030b7b1f 100644 (file)
--- a/lib/ringbuffer/ring_buffer_frontend.c
+++ b/lib/ringbuffer/ring_buffer_frontend.c
@@ -247,7 +247,8 @@ int lib_ring_buffer_create(struct lib_ring_buffer *buf,
                kzalloc_node(ALIGN(sizeof(*buf->commit_hot)
                                   * chan->backend.num_subbuf,
                                   1 << INTERNODE_CACHE_SHIFT),
-                       GFP_KERNEL, cpu_to_node(max(cpu, 0)));
+                       GFP_KERNEL | __GFP_NOWARN,
+                       cpu_to_node(max(cpu, 0)));
        if (!buf->commit_hot) {
                ret = -ENOMEM;
                goto free_chanbuf;
@@ -257,7 +258,8 @@ int lib_ring_buffer_create(struct lib_ring_buffer *buf,
                kzalloc_node(ALIGN(sizeof(*buf->commit_cold)
                                   * chan->backend.num_subbuf,
                                   1 << INTERNODE_CACHE_SHIFT),
-                       GFP_KERNEL, cpu_to_node(max(cpu, 0)));
+                       GFP_KERNEL | __GFP_NOWARN,
+                       cpu_to_node(max(cpu, 0)));
        if (!buf->commit_cold) {
                ret = -ENOMEM;
                goto free_commit;
@@ -1980,6 +1982,33 @@ void lib_ring_buffer_vmcore_check_deliver(const struct lib_ring_buffer_config *c
                v_set(config, &buf->commit_hot[idx].seq, commit_count);
 }
 
+/*
+ * The ring buffer can count events recorded and overwritten per buffer,
+ * but it is disabled by default due to its performance overhead.
+ */
+#ifdef LTTNG_RING_BUFFER_COUNT_EVENTS
+static
+void deliver_count_events(const struct lib_ring_buffer_config *config,
+               struct lib_ring_buffer *buf,
+               unsigned long idx)
+{
+       v_add(config, subbuffer_get_records_count(config,
+                       &buf->backend, idx),
+               &buf->records_count);
+       v_add(config, subbuffer_count_records_overrun(config,
+                       &buf->backend, idx),
+               &buf->records_overrun);
+}
+#else /* LTTNG_RING_BUFFER_COUNT_EVENTS */
+static
+void deliver_count_events(const struct lib_ring_buffer_config *config,
+               struct lib_ring_buffer *buf,
+               unsigned long idx)
+{
+}
+#endif /* #else LTTNG_RING_BUFFER_COUNT_EVENTS */
+
+
 void lib_ring_buffer_check_deliver_slow(const struct lib_ring_buffer_config *config,
                                   struct lib_ring_buffer *buf,
                                   struct channel *chan,
@@ -2032,15 +2061,7 @@ void lib_ring_buffer_check_deliver_slow(const struct lib_ring_buffer_config *con
                 * and any other writer trying to access this subbuffer
                 * in this state is required to drop records.
                 */
-               v_add(config,
-                     subbuffer_get_records_count(config,
-                                                 &buf->backend, idx),
-                     &buf->records_count);
-               v_add(config,
-                     subbuffer_count_records_overrun(config,
-                                                     &buf->backend,
-                                                     idx),
-                     &buf->records_overrun);
+               deliver_count_events(config, buf, idx);
                config->cb.buffer_end(buf, tsc, idx,
                                      lib_ring_buffer_get_data_size(config,
                                                                buf,