Extract the lost packets and discarded events counters
[lttng-tools.git] / src / common / ust-consumer / ust-consumer.c
index 44bcfdc374d9a0bd9b2ce869059fa912794a19c1..a17c48f2f9ba2639fd39754550e8c1eacddacb86 100644 (file)
@@ -1666,6 +1666,105 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                health_code_update();
                break;
        }
+       case LTTNG_CONSUMER_DISCARDED_EVENTS:
+       {
+               uint64_t ret;
+               struct lttng_ht_iter iter;
+               struct lttng_ht *ht;
+               struct lttng_consumer_stream *stream;
+               uint64_t id = msg.u.discarded_events.session_id;
+               uint64_t key = msg.u.discarded_events.channel_key;
+
+               DBG("UST consumer discarded events command for session id %"
+                               PRIu64, id);
+               rcu_read_lock();
+               pthread_mutex_lock(&consumer_data.lock);
+
+               ht = consumer_data.stream_list_ht;
+
+               /*
+                * We only need a reference to the channel, but they are not
+                * directly indexed, so we just use the first matching stream
+                * to extract the information we need, we default to 0 if not
+                * found (no events are dropped if the channel is not yet in
+                * use).
+                */
+               ret = 0;
+               cds_lfht_for_each_entry_duplicate(ht->ht,
+                               ht->hash_fct(&id, lttng_ht_seed),
+                               ht->match_fct, &id,
+                               &iter.iter, stream, node_session_id.node) {
+                       if (stream->chan->key == key) {
+                               ret = stream->chan->discarded_events;
+                               break;
+                       }
+               }
+               pthread_mutex_unlock(&consumer_data.lock);
+               rcu_read_unlock();
+
+               DBG("UST consumer discarded events command for session id %"
+                               PRIu64 ", channel key %" PRIu64, id, key);
+
+               health_code_update();
+
+               /* Send back returned value to session daemon */
+               ret = lttcomm_send_unix_sock(sock, &ret, sizeof(ret));
+               if (ret < 0) {
+                       PERROR("send discarded events");
+                       goto error_fatal;
+               }
+
+               break;
+       }
+       case LTTNG_CONSUMER_LOST_PACKETS:
+       {
+               uint64_t ret;
+               struct lttng_ht_iter iter;
+               struct lttng_ht *ht;
+               struct lttng_consumer_stream *stream;
+               uint64_t id = msg.u.lost_packets.session_id;
+               uint64_t key = msg.u.lost_packets.channel_key;
+
+               DBG("UST consumer lost packets command for session id %"
+                               PRIu64, id);
+               rcu_read_lock();
+               pthread_mutex_lock(&consumer_data.lock);
+
+               ht = consumer_data.stream_list_ht;
+
+               /*
+                * We only need a reference to the channel, but they are not
+                * directly indexed, so we just use the first matching stream
+                * to extract the information we need, we default to 0 if not
+                * found (no packets lost if the channel is not yet in use).
+                */
+               ret = 0;
+               cds_lfht_for_each_entry_duplicate(ht->ht,
+                               ht->hash_fct(&id, lttng_ht_seed),
+                               ht->match_fct, &id,
+                               &iter.iter, stream, node_session_id.node) {
+                       if (stream->chan->key == key) {
+                               ret = stream->chan->lost_packets;
+                               break;
+                       }
+               }
+               pthread_mutex_unlock(&consumer_data.lock);
+               rcu_read_unlock();
+
+               DBG("UST consumer lost packets command for session id %"
+                               PRIu64 ", channel key %" PRIu64, id, key);
+
+               health_code_update();
+
+               /* Send back returned value to session daemon */
+               ret = lttcomm_send_unix_sock(sock, &ret, sizeof(ret));
+               if (ret < 0) {
+                       PERROR("send lost packets");
+                       goto error_fatal;
+               }
+
+               break;
+       }
        default:
                break;
        }
@@ -1808,6 +1907,16 @@ int lttng_ustconsumer_get_current_timestamp(
        return ustctl_get_current_timestamp(stream->ustream, ts);
 }
 
+int lttng_ustconsumer_get_sequence_number(
+               struct lttng_consumer_stream *stream, uint64_t *seq)
+{
+       assert(stream);
+       assert(stream->ustream);
+       assert(seq);
+
+       return ustctl_get_sequence_number(stream->ustream, seq);
+}
+
 /*
  * Called when the stream signal the consumer that it has hang up.
  */
@@ -2104,6 +2213,61 @@ end:
        return ret;
 }
 
+static
+int update_stream_stats(struct lttng_consumer_stream *stream)
+{
+       int ret;
+       uint64_t seq, discarded;
+
+       ret = ustctl_get_sequence_number(stream->ustream, &seq);
+       if (ret < 0) {
+               PERROR("ustctl_get_sequence_number");
+               goto end;
+       }
+       /*
+        * Start the sequence when we extract the first packet in case we don't
+        * start at 0 (for example if a consumer is not connected to the
+        * session immediately after the beginning).
+        */
+       if (stream->last_sequence_number == -1ULL) {
+               stream->last_sequence_number = seq;
+       } else if (seq > stream->last_sequence_number) {
+               stream->chan->lost_packets += seq -
+                               stream->last_sequence_number - 1;
+       } else {
+               /* seq <= last_sequence_number */
+               ERR("Sequence number inconsistent : prev = %" PRIu64
+                               ", current = %" PRIu64,
+                               stream->last_sequence_number, seq);
+               ret = -1;
+               goto end;
+       }
+       stream->last_sequence_number = seq;
+
+       ret = ustctl_get_events_discarded(stream->ustream, &discarded);
+       if (ret < 0) {
+               PERROR("kernctl_get_events_discarded");
+               goto end;
+       }
+       if (discarded < stream->last_discarded_events) {
+               /*
+                * Overflow has occured. We assume only one wrap-around
+                * has occured.
+                */
+               stream->chan->discarded_events +=
+                               (1ULL << (CAA_BITS_PER_LONG - 1)) -
+                               stream->last_discarded_events + discarded;
+       } else {
+               stream->chan->discarded_events += discarded -
+                               stream->last_discarded_events;
+       }
+       stream->last_discarded_events = discarded;
+       ret = 0;
+
+end:
+       return ret;
+}
+
 /*
  * Read subbuffer from the given stream.
  *
@@ -2187,6 +2351,13 @@ retry:
                if (ret < 0) {
                        goto end;
                }
+
+               /* Update the stream's sequence and discarded events count. */
+               ret = update_stream_stats(stream);
+               if (ret < 0) {
+                       PERROR("kernctl_get_events_discarded");
+                       goto end;
+               }
        } else {
                write_index = 0;
        }
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