From: Julien Desfossez <jdesfossez@efficios.com>
Date: Mon, 21 Oct 2013 04:00:34 +0000 (-0400)
Subject: Documentation : --help and manpage for live streaming
X-Git-Tag: v0.3~69
X-Git-Url: http://git.lttng.org/?p=lttngtop.git;a=commitdiff_plain;h=bab469fc468832ae02c61e24bf3afaba24228c09

Documentation : --help and manpage for live streaming

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
---

diff --git a/doc/lttngtop.1 b/doc/lttngtop.1
index 0f4614e..f83af75 100644
--- a/doc/lttngtop.1
+++ b/doc/lttngtop.1
@@ -48,14 +48,35 @@ launched as root.
 
 .nf
 lttng create lttngtop
-lttng enable-event -k -a
-lttng add-context -k -t pid -t procname -t tid -t ppid -t perf:cache-misses -t perf:major-faults -t perf:branch-load-misses
-lttng start
+lttng enable-event -k lttng_statedump_start,lttng_statedump_end,lttng_statedump_process_state,lttng_statedump_file_descriptor,lttng_statedump_vm_map,lttng_statedump_network_interface,lttng_statedump_interrupt,sched_process_free,sched_switch -s lttngtop
+lttng enable-event -k --syscall -a -s lttngtop
+lttng add-context -k -t pid -t procname -t tid -t ppid -t perf:cache-misses -t perf:major-faults -t perf:branch-load-misses -s lttngtop
+lttng start lttngtop
 sleep 10
-lttng stop
-lttng destroy
+lttng stop lttngtop
+lttng destroy lttngtop
 .fi
 
+.SH "LIVE STREAMING"
+
+.PP
+In addition to offline traces, LTTngTop can read traces while they are being recorded.
+The official supported way of doing live streaming is using lttng-tools >=2.4 and
+following the documentation in live-reading-howto.txt.
+An other experimental way of doing live tracing is with mmap, but this requires some
+more work because is not officially supported and requires out-of-tree patches to
+lttng-tools and babeltrace.
+
+.PP
+To use the network live-reading, the user only needs to specify the relayd hostname
+or IP address with the option -r. For now, LTTngTop will only connect to the first
+live session established on the relay, but in a near future, the user will be able
+to choose which session to attach to.
+
+The default mode after attaching to a session is to start reading the trace from
+this point in time. In order to read the trace from the beginning, the user can specify
+the -b option.
+
 .SH "KEY BINDINGS"
 
 .TP 7
diff --git a/src/lttngtop.c b/src/lttngtop.c
index 8cec6d5..bfae663 100644
--- a/src/lttngtop.c
+++ b/src/lttngtop.c
@@ -548,6 +548,8 @@ void usage(FILE *fp)
 	fprintf(fp, "  -f, --child              Follow threads associated with selected PIDs\n");
 	fprintf(fp, "  -n, --hostname           Comma-separated list of hostnames to display (require hostname context in trace)\n");
 	fprintf(fp, "  -k, --kprobes            Comma-separated list of kprobes to insert (same format as lttng enable-event)\n");
+	fprintf(fp, "  -r, --relay-hostname     Network live streaming : hostname of the lttng-relayd (default port)\n");
+	fprintf(fp, "  -b, --begin              Network live streaming : read the trace for the beginning of the recording\n");
 }
 
 /*