Fix: update next_net_seq_num after sending header

[lttng-tools.git] / src / common / consumer.h

diff --git a/src/common/consumer.h b/src/common/consumer.h
index 193533e926e12ea9b392686b24ff5559fccd8efb..830514659772b0afa6bb5de1ad7be678e033dcfb 100644 (file)
--- a/src/common/consumer.h
+++ b/src/common/consumer.h
@@ -129,7 +129,19 @@ struct lttng_consumer_stream {
        unsigned int metadata_flag;
        /* Used when the stream is set for network streaming */
        uint64_t relayd_stream_id;
-       /* Next sequence number to use for trace packet */
+       /*
+        * When sending a stream packet to a relayd, this number is used to track
+        * the packet sent by the consumer and seen by the relayd. When sending the
+        * data header to the relayd, this number is sent and if the transmission
+        * was successful, it is incremented.
+        *
+        * Even if the full data is not fully transmitted it won't matter since
+        * only two possible error can happen after that where either the relayd
+        * died or a read error is detected on the stream making this value useless
+        * after that.
+        *
+        * This value SHOULD be read/updated atomically or with the lock acquired.
+        */
        uint64_t next_net_seq_num;
        /*
         * Lock to use the stream FDs since they are used between threads.