return outfd;
}
+/*
+ * Write a character on the metadata poll pipe to wake the metadata thread.
+ * Returns 0 on success, -1 on error.
+ */
+int consumer_metadata_wakeup_pipe(const struct lttng_consumer_channel *channel)
+{
+ int ret = 0;
+
+ DBG("Waking up metadata poll thread (writing to pipe): channel name = '%s'",
+ channel->name);
+ if (channel->monitor && channel->metadata_stream) {
+ const char dummy = 'c';
+ const ssize_t write_ret = lttng_write(
+ channel->metadata_stream->ust_metadata_poll_pipe[1],
+ &dummy, 1);
+
+ if (write_ret < 1) {
+ if (errno == EWOULDBLOCK) {
+ /*
+ * This is fine, the metadata poll thread
+ * is having a hard time keeping-up, but
+ * it will eventually wake-up and consume
+ * the available data.
+ */
+ ret = 0;
+ } else {
+ PERROR("Failed to write to UST metadata pipe while attempting to wake-up the metadata poll thread");
+ ret = -1;
+ goto end;
+ }
+ }
+ }
+
+end:
+ return ret;
+}
+
/*
* Trigger a dump of the metadata content. Following/during the succesful
* completion of this call, the metadata poll thread will start receiving
err = 0; /* All is OK */
goto end;
}
- DBG("received command on sock");
+ DBG("Received command on sock");
}
/* All is OK */
err = 0;
return NULL;
}
+static int post_consume(struct lttng_consumer_stream *stream,
+ const struct stream_subbuffer *subbuffer,
+ struct lttng_consumer_local_data *ctx)
+{
+ size_t i;
+ int ret = 0;
+ const size_t count = lttng_dynamic_array_get_count(
+ &stream->read_subbuffer_ops.post_consume_cbs);
+
+ for (i = 0; i < count; i++) {
+ const post_consume_cb op = *(post_consume_cb *) lttng_dynamic_array_get_element(
+ &stream->read_subbuffer_ops.post_consume_cbs,
+ i);
+
+ ret = op(stream, subbuffer, ctx);
+ if (ret) {
+ goto end;
+ }
+ }
+end:
+ return ret;
+}
+
ssize_t lttng_consumer_read_subbuffer(struct lttng_consumer_stream *stream,
struct lttng_consumer_local_data *ctx,
bool locked_by_caller)
written_bytes = stream->read_subbuffer_ops.consume_subbuffer(
ctx, stream, &subbuffer);
- /*
- * Should write subbuf_size amount of data when network streaming or
- * the full padded size when we are not streaming.
- */
- if ((written_bytes != subbuffer.info.data.subbuf_size &&
- stream->net_seq_idx != (uint64_t) -1ULL) ||
- (written_bytes != subbuffer.info.data.padded_subbuf_size &&
- stream->net_seq_idx ==
- (uint64_t) -1ULL)) {
- /*
- * Display the error but continue processing to try to
- * release the subbuffer. This is a DBG statement
- * since this can happen without being a critical
- * error.
- */
- DBG("Failed to write to tracefile (written_bytes: %zd != padded subbuffer size: %lu, subbuffer size: %lu)",
- written_bytes, subbuffer.info.data.subbuf_size,
- subbuffer.info.data.padded_subbuf_size);
+ if (written_bytes <= 0) {
+ ERR("Error consuming subbuffer: (%zd)", written_bytes);
+ ret = (int) written_bytes;
+ goto error_put_subbuf;
}
ret = stream->read_subbuffer_ops.put_next_subbuffer(stream, &subbuffer);
goto end;
}
- if (stream->read_subbuffer_ops.post_consume) {
- ret = stream->read_subbuffer_ops.post_consume(stream, &subbuffer, ctx);
- if (ret) {
- goto end;
- }
+ ret = post_consume(stream, &subbuffer, ctx);
+ if (ret) {
+ goto end;
}
/*
ERR("Stream rotation error after consuming data");
goto end;
}
+
} else if (rotation_ret < 0) {
ret = rotation_ret;
ERR("Failed to check if stream was ready to rotate after consuming data");
return start_pos;
}
-static
-int consumer_flush_buffer(struct lttng_consumer_stream *stream, int producer_active)
+/* Stream lock must be held by the caller. */
+static int sample_stream_positions(struct lttng_consumer_stream *stream,
+ unsigned long *produced, unsigned long *consumed)
{
- int ret = 0;
+ int ret;
- switch (consumer_data.type) {
- case LTTNG_CONSUMER_KERNEL:
- if (producer_active) {
- ret = kernctl_buffer_flush(stream->wait_fd);
- if (ret < 0) {
- ERR("Failed to flush kernel stream");
- goto end;
- }
- } else {
- ret = kernctl_buffer_flush_empty(stream->wait_fd);
- if (ret < 0) {
- /*
- * Doing a buffer flush which does not take into
- * account empty packets. This is not perfect,
- * but required as a fall-back when
- * "flush_empty" is not implemented by
- * lttng-modules.
- */
- ret = kernctl_buffer_flush(stream->wait_fd);
- if (ret < 0) {
- ERR("Failed to flush kernel stream");
- goto end;
- }
- }
- }
- break;
- case LTTNG_CONSUMER32_UST:
- case LTTNG_CONSUMER64_UST:
- lttng_ustconsumer_flush_buffer(stream, producer_active);
- break;
- default:
- ERR("Unknown consumer_data type");
- abort();
+ ASSERT_LOCKED(stream->lock);
+
+ ret = lttng_consumer_sample_snapshot_positions(stream);
+ if (ret < 0) {
+ ERR("Failed to sample snapshot positions");
+ goto end;
+ }
+
+ ret = lttng_consumer_get_produced_snapshot(stream, produced);
+ if (ret < 0) {
+ ERR("Failed to sample produced position");
+ goto end;
+ }
+
+ ret = lttng_consumer_get_consumed_snapshot(stream, consumed);
+ if (ret < 0) {
+ ERR("Failed to sample consumed position");
+ goto end;
}
end:
const bool is_local_trace = relayd_id == -1ULL;
struct consumer_relayd_sock_pair *relayd = NULL;
bool rotating_to_new_chunk = true;
+ /* Array of `struct lttng_consumer_stream *` */
+ struct lttng_dynamic_pointer_array streams_packet_to_open;
+ size_t stream_idx;
DBG("Consumer sample rotate position for channel %" PRIu64, key);
lttng_dynamic_array_init(&stream_rotation_positions,
sizeof(struct relayd_stream_rotation_position), NULL);
+ lttng_dynamic_pointer_array_init(&streams_packet_to_open, NULL);
rcu_read_lock();
}
/*
- * Do not flush an empty packet when rotating from a NULL trace
+ * Do not flush a packet when rotating from a NULL trace
* chunk. The stream has no means to output data, and the prior
- * rotation which rotated to NULL performed that side-effect already.
+ * rotation which rotated to NULL performed that side-effect
+ * already. No new data can be produced when a stream has no
+ * associated trace chunk (e.g. a stop followed by a rotate).
*/
if (stream->trace_chunk) {
+ bool flush_active;
+
+ if (stream->metadata_flag) {
+ /*
+ * Don't produce an empty metadata packet,
+ * simply close the current one.
+ *
+ * Metadata is regenerated on every trace chunk
+ * switch; there is no concern that no data was
+ * produced.
+ */
+ flush_active = true;
+ } else {
+ /*
+ * Only flush an empty packet if the "packet
+ * open" could not be performed on transition
+ * to a new trace chunk and no packets were
+ * consumed within the chunk's lifetime.
+ */
+ if (stream->opened_packet_in_current_trace_chunk) {
+ flush_active = true;
+ } else {
+ /*
+ * Stream could have been full at the
+ * time of rotation, but then have had
+ * no activity at all.
+ *
+ * It is important to flush a packet
+ * to prevent 0-length files from being
+ * produced as most viewers choke on
+ * them.
+ *
+ * Unfortunately viewers will not be
+ * able to know that tracing was active
+ * for this stream during this trace
+ * chunk's lifetime.
+ */
+ ret = sample_stream_positions(stream, &produced_pos, &consumed_pos);
+ if (ret) {
+ goto end_unlock_stream;
+ }
+
+ /*
+ * Don't flush an empty packet if data
+ * was produced; it will be consumed
+ * before the rotation completes.
+ */
+ flush_active = produced_pos != consumed_pos;
+ if (!flush_active) {
+ const char *trace_chunk_name;
+ uint64_t trace_chunk_id;
+
+ chunk_status = lttng_trace_chunk_get_name(
+ stream->trace_chunk,
+ &trace_chunk_name,
+ NULL);
+ if (chunk_status == LTTNG_TRACE_CHUNK_STATUS_NONE) {
+ trace_chunk_name = "none";
+ }
+
+ /*
+ * Consumer trace chunks are
+ * never anonymous.
+ */
+ chunk_status = lttng_trace_chunk_get_id(
+ stream->trace_chunk,
+ &trace_chunk_id);
+ assert(chunk_status ==
+ LTTNG_TRACE_CHUNK_STATUS_OK);
+
+ DBG("Unable to open packet for stream during trace chunk's lifetime. "
+ "Flushing an empty packet to prevent an empty file from being created: "
+ "stream id = %" PRIu64 ", trace chunk name = `%s`, trace chunk id = %" PRIu64,
+ stream->key, trace_chunk_name, trace_chunk_id);
+ }
+ }
+ }
+
/*
- * For metadata stream, do an active flush, which does not
- * produce empty packets. For data streams, empty-flush;
- * ensures we have at least one packet in each stream per trace
- * chunk, even if no data was produced.
+ * Close the current packet before sampling the
+ * ring buffer positions.
*/
- ret = consumer_flush_buffer(stream, stream->metadata_flag ? 1 : 0);
+ ret = consumer_stream_flush_buffer(stream, flush_active);
if (ret < 0) {
ERR("Failed to flush stream %" PRIu64 " during channel rotation",
stream->key);
}
stream_count++;
}
+
+ stream->opened_packet_in_current_trace_chunk = false;
+
+ if (rotating_to_new_chunk && !stream->metadata_flag) {
+ /*
+ * Attempt to flush an empty packet as close to the
+ * rotation point as possible. In the event where a
+ * stream remains inactive after the rotation point,
+ * this ensures that the new trace chunk has a
+ * beginning timestamp set at the begining of the
+ * trace chunk instead of only creating an empty
+ * packet when the trace chunk is stopped.
+ *
+ * This indicates to the viewers that the stream
+ * was being recorded, but more importantly it
+ * allows viewers to determine a useable trace
+ * intersection.
+ *
+ * This presents a problem in the case where the
+ * ring-buffer is completely full.
+ *
+ * Consider the following scenario:
+ * - The consumption of data is slow (slow network,
+ * for instance),
+ * - The ring buffer is full,
+ * - A rotation is initiated,
+ * - The flush below does nothing (no space left to
+ * open a new packet),
+ * - The other streams rotate very soon, and new
+ * data is produced in the new chunk,
+ * - This stream completes its rotation long after the
+ * rotation was initiated
+ * - The session is stopped before any event can be
+ * produced in this stream's buffers.
+ *
+ * The resulting trace chunk will have a single packet
+ * temporaly at the end of the trace chunk for this
+ * stream making the stream intersection more narrow
+ * than it should be.
+ *
+ * To work-around this, an empty flush is performed
+ * after the first consumption of a packet during a
+ * rotation if open_packet fails. The idea is that
+ * consuming a packet frees enough space to switch
+ * packets in this scenario and allows the tracer to
+ * "stamp" the beginning of the new trace chunk at the
+ * earliest possible point.
+ *
+ * The packet open is performed after the channel
+ * rotation to ensure that no attempt to open a packet
+ * is performed in a stream that has no active trace
+ * chunk.
+ */
+ ret = lttng_dynamic_pointer_array_add_pointer(
+ &streams_packet_to_open, stream);
+ if (ret) {
+ PERROR("Failed to add a stream pointer to array of streams in which to open a packet");
+ ret = -1;
+ goto end_unlock_stream;
+ }
+ }
+
pthread_mutex_unlock(&stream->lock);
}
stream = NULL;
- pthread_mutex_unlock(&channel->lock);
- if (is_local_trace) {
- ret = 0;
- goto end;
- }
+ if (!is_local_trace) {
+ relayd = consumer_find_relayd(relayd_id);
+ if (!relayd) {
+ ERR("Failed to find relayd %" PRIu64, relayd_id);
+ ret = -1;
+ goto end_unlock_channel;
+ }
- relayd = consumer_find_relayd(relayd_id);
- if (!relayd) {
- ERR("Failed to find relayd %" PRIu64, relayd_id);
- ret = -1;
- goto end;
+ pthread_mutex_lock(&relayd->ctrl_sock_mutex);
+ ret = relayd_rotate_streams(&relayd->control_sock, stream_count,
+ rotating_to_new_chunk ? &next_chunk_id : NULL,
+ (const struct relayd_stream_rotation_position *)
+ stream_rotation_positions.buffer
+ .data);
+ pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
+ if (ret < 0) {
+ ERR("Relayd rotate stream failed. Cleaning up relayd %" PRIu64,
+ relayd->net_seq_idx);
+ lttng_consumer_cleanup_relayd(relayd);
+ goto end_unlock_channel;
+ }
}
- pthread_mutex_lock(&relayd->ctrl_sock_mutex);
- ret = relayd_rotate_streams(&relayd->control_sock, stream_count,
- rotating_to_new_chunk ? &next_chunk_id : NULL,
- (const struct relayd_stream_rotation_position *)
- stream_rotation_positions.buffer.data);
- pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
- if (ret < 0) {
- ERR("Relayd rotate stream failed. Cleaning up relayd %" PRIu64,
- relayd->net_seq_idx);
- lttng_consumer_cleanup_relayd(relayd);
- goto end;
+ for (stream_idx = 0;
+ stream_idx < lttng_dynamic_pointer_array_get_count(
+ &streams_packet_to_open);
+ stream_idx++) {
+ enum consumer_stream_open_packet_status status;
+
+ stream = lttng_dynamic_pointer_array_get_pointer(
+ &streams_packet_to_open, stream_idx);
+
+ pthread_mutex_lock(&stream->lock);
+ status = consumer_stream_open_packet(stream);
+ pthread_mutex_unlock(&stream->lock);
+ switch (status) {
+ case CONSUMER_STREAM_OPEN_PACKET_STATUS_OPENED:
+ DBG("Opened a packet after a rotation: stream id = %" PRIu64
+ ", channel name = %s, session id = %" PRIu64,
+ stream->key, stream->chan->name,
+ stream->chan->session_id);
+ break;
+ case CONSUMER_STREAM_OPEN_PACKET_STATUS_NO_SPACE:
+ /*
+ * Can't open a packet as there is no space left
+ * in the buffer. A new packet will be opened
+ * once one has been consumed.
+ */
+ DBG("No space left to open a packet after a rotation: stream id = %" PRIu64
+ ", channel name = %s, session id = %" PRIu64,
+ stream->key, stream->chan->name,
+ stream->chan->session_id);
+ break;
+ case CONSUMER_STREAM_OPEN_PACKET_STATUS_ERROR:
+ /* Logged by callee. */
+ ret = -1;
+ goto end_unlock_channel;
+ default:
+ abort();
+ }
}
+ pthread_mutex_unlock(&channel->lock);
ret = 0;
goto end;
end:
rcu_read_unlock();
lttng_dynamic_array_reset(&stream_rotation_positions);
+ lttng_dynamic_pointer_array_reset(&streams_packet_to_open);
return ret;
}
{
int ret;
- ret = consumer_flush_buffer(stream, 1);
+ ret = consumer_stream_flush_buffer(stream, 1);
if (ret < 0) {
ERR("Failed to flush stream %" PRIu64 " during channel clear",
stream->key);
} else {
relayd_id_str = "(formatting error)";
}
- }
+ }
- /* Local protocol error. */
+ /* Local protocol error. */
assert(chunk_creation_timestamp);
ret = time_to_iso8601_str(chunk_creation_timestamp,
creation_timestamp_buffer,
} else {
relayd_id_str = "(formatting error)";
}
- }
+ }
DBG("Consumer trace chunk exists command: relayd_id = %s"
", chunk_id = %" PRIu64, relayd_id_str,
end:
return ret;
}
+
+enum lttcomm_return_code lttng_consumer_open_channel_packets(
+ struct lttng_consumer_channel *channel)
+{
+ struct lttng_consumer_stream *stream;
+ enum lttcomm_return_code ret = LTTCOMM_CONSUMERD_SUCCESS;
+
+ if (channel->metadata_stream) {
+ ERR("Open channel packets command attempted on a metadata channel");
+ ret = LTTCOMM_CONSUMERD_INVALID_PARAMETERS;
+ goto end;
+ }
+
+ rcu_read_lock();
+ cds_list_for_each_entry(stream, &channel->streams.head, send_node) {
+ enum consumer_stream_open_packet_status status;
+
+ pthread_mutex_lock(&stream->lock);
+ if (cds_lfht_is_node_deleted(&stream->node.node)) {
+ goto next;
+ }
+
+ status = consumer_stream_open_packet(stream);
+ switch (status) {
+ case CONSUMER_STREAM_OPEN_PACKET_STATUS_OPENED:
+ DBG("Opened a packet in \"open channel packets\" command: stream id = %" PRIu64
+ ", channel name = %s, session id = %" PRIu64,
+ stream->key, stream->chan->name,
+ stream->chan->session_id);
+ stream->opened_packet_in_current_trace_chunk = true;
+ break;
+ case CONSUMER_STREAM_OPEN_PACKET_STATUS_NO_SPACE:
+ DBG("No space left to open a packet in \"open channel packets\" command: stream id = %" PRIu64
+ ", channel name = %s, session id = %" PRIu64,
+ stream->key, stream->chan->name,
+ stream->chan->session_id);
+ break;
+ case CONSUMER_STREAM_OPEN_PACKET_STATUS_ERROR:
+ /*
+ * Only unexpected internal errors can lead to this
+ * failing. Report an unknown error.
+ */
+ ERR("Failed to flush empty buffer in \"open channel packets\" command: stream id = %" PRIu64
+ ", channel id = %" PRIu64
+ ", channel name = %s"
+ ", session id = %" PRIu64,
+ stream->key, channel->key,
+ channel->name, channel->session_id);
+ ret = LTTCOMM_CONSUMERD_UNKNOWN_ERROR;
+ goto error_unlock;
+ default:
+ abort();
+ }
+
+ next:
+ pthread_mutex_unlock(&stream->lock);
+ }
+
+end_rcu_unlock:
+ rcu_read_unlock();
+end:
+ return ret;
+
+error_unlock:
+ pthread_mutex_unlock(&stream->lock);
+ goto end_rcu_unlock;
+}
projects / lttng-tools.git / blobdiff