Fix: deny overwrite mode and num subbuf less than 2

[lttng-tools.git] / doc / man / lttng.1

diff --git a/doc/man/lttng.1 b/doc/man/lttng.1
index ef73b062cd558ea5017957c38ea475adc29c8066..09c77d1d3a99feee543c4e96fc7a5555423d0d35 100644 (file)
--- a/doc/man/lttng.1
+++ b/doc/man/lttng.1
@@ -402,7 +402,8 @@ Apply to the user-space tracer
 Discard event when subbuffers are full (default)
 .TP
 .BR "\-\-overwrite"
-Flight recorder mode : overwrites events when subbuffers are full
+Flight recorder mode: overwrites events when subbuffers are full. The
+number of subbuffer must be 2 or more.
 .TP
 .BR "\-\-subbuf-size SIZE"
 Subbuffer size in bytes {+k,+M,+G}.
@@ -442,6 +443,8 @@ Use shared buffer for the whole system (\-k only)
 .BR "\-C, \-\-tracefile-size SIZE"
 Maximum size of each tracefile within a stream (in bytes).
 0 means unlimited. (default: 0)
+Note: traces generated with this option may inaccurately report
+discarded events as per CTF 1.8.
 .TP
 .BR "\-W, \-\-tracefile-count COUNT"
 Used in conjunction with \-C option, this will limit the number of files
@@ -587,6 +590,11 @@ running applications can be found under columns "PID" and "LWP" of the
   '$ctx.vtid == 1234'
 .fi
 
+Context information is available to all filters whether or not the add-context
+command has been used to add it to the event's channel, as long as the context
+field exists for that domain. For example, the filter examples given above will
+never fail to link: no add-context is required for the event's channel.
+
 .TP
 .BR "\-x, \-\-exclude LIST"
 Add exclusions to UST tracepoints: