perf record: Document --group option
The 'perf record --group' option lacks documentation and confuses users.
As -e/--event option already supports group spec, it should not be used
anymore.
Also add a short description of event group itself.
Reported-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1425266013-5034-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index 4d66894..355c4f5 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -55,6 +55,11 @@
If you want to profile write accesses in [0x1000~1008), just set
'mem:0x1000/8:w'.
+ - a group of events surrounded by a pair of brace ("{event1,event2,...}").
+ Each event is separated by commas and the group should be quoted to
+ prevent the shell interpretation. You also need to use --group on
+ "perf report" to view group events together.
+
--filter=<filter>::
Event filter.
@@ -104,6 +109,10 @@
specification with appended unit character - B/K/M/G. The
size is rounded up to have nearest pages power of two value.
+--group::
+ Put all events in a single event group. This precedes the --event
+ option and remains only for backward compatibility. See --event.
+
-g::
Enables call-graph (stack chain/backtrace) recording.