'perf lock report' reports statistical data.
 
-OPTIONS
--------
+COMMON OPTIONS
+--------------
 
 -i::
 --input=<file>::
 --dump-raw-trace::
         Dump raw trace in ASCII.
 
+REPORT OPTIONS
+--------------
+
+-k::
+--key=<value>::
+        Sorting key. Possible values: acquired (default), contended,
+        wait_total, wait_max, wait_min.
+
 SEE ALSO
 --------
 linkperf:perf[1]
 
 
 static const struct option report_options[] = {
        OPT_STRING('k', "key", &sort_key, "acquired",
-                   "key for sorting"),
+                   "key for sorting (acquired / contended / wait_total / wait_max / wait_min)"),
        /* TODO: type */
        OPT_END()
 };