perf lock: Document valid sort keys

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20110222205312.GA18474@joi.lan>
Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/perf-lock.txt

@@ -24,8 +24,8 @@ and statistics with this 'perf lock' command.
 
   'perf lock report' reports statistical data.
 
-OPTIONS
+COMMON OPTIONS
--------
+--------------
 
 -i::
 --input=<file>::
@@ -39,6 +39,14 @@ OPTIONS
 --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]

tools/perf/builtin-lock.c

@@ -893,7 +893,7 @@ static const char * const report_usage[] = {
 
 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()
 };