babeltrace2-source.ctf.fs(7): document the overlapping snapshot feature

Signed-off-by: Philippe Proulx <[email protected]> Change-Id: I482a366679f65a577cb7081ce46736ab484858c3 Reviewed-on: https://review.lttng.org/c/babeltrace/+/2395
efficios · Nov 15, 2019 · e3db68e · e3db68e
1 parent f7bfe75
commit e3db68e
Showing 1 changed file with 8 additions and 0 deletions.
diff --git a/doc/man/babeltrace2-source.ctf.fs.7.txt b/doc/man/babeltrace2-source.ctf.fs.7.txt
@@ -67,6 +67,14 @@ More than one physical CTF data stream file can support a single logical
 CTF data stream (LTTng's trace file rotation and tracing session
 rotation can cause this).
 
+If two or more data stream files contain the same packets, a
+compcls:source.ctf.fs message iterator reads each of  them only once so
+that it never emits duplicated messages. This feature makes it possible,
+for example, to open overlapping
+https://lttng.org/docs/#doc-taking-a-snapshot[LTTng snapshots] with a
+single compcls:source.ctf.fs component and silently discard the
+duplicated packets.
+
 
 === Trace quirks