[PATCH] perf report: Add support to display group output for non group events

[Jiri Olsa <jolsa@redhat.com>]

On Wed, Feb 07, 2018 at 10:52:35AM -0800, Stephane Eranian wrote:

SNIP

> >> Similar to what I get if I do instead:
> >> $ perf record -e '{branches,branches,branches,branches}' my_test
> >> $ perf report --group
> >>
> >> But here, I would have to ensure all events fits in a group to allow
> >> the reporting
> >> I want. So that would limit me to 4 events.
> >>
> >> I think perf report --group should work regardless of how the events
> >> were grouped.
> >> Is there already a way to work around this?
> >
> > no workaround.. please try attached patch, it seems
> > to work for what you described
> >
> Works for me. That's great!
> Thanks.
> 
> Tested-By: Stephane Eranian <eranian@google.com>

thanks, full patch attached

jirka


---
Add support to display group output for if non grouped events
are detected and user forces --group option. Now for non-group
events recorded like:

  $ perf record -e 'cycles,instructions' ls

you can still get group output by using --group option
in report:

  $ perf report --group --stdio
  ...
  #         Overhead  Command  Shared Object     Symbol
  # ................  .......  ................  ......................
  #
      17.67%   0.00%  ls       libc-2.25.so      [.] _IO_do_write@@GLIB
      15.59%  25.94%  ls       ls                [.] calculate_columns
      15.41%  31.35%  ls       libc-2.25.so      [.] __strcoll_l
  ...

Requested-and-Tested-by: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-m1ffikw8c3a55b3uaxrmk5w3@git.kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/perf/Documentation/perf-report.txt | 3 ++-
 tools/perf/builtin-report.c              | 6 +++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/tools/perf/Documentation/perf-report.txt b/tools/perf/Documentation/perf-report.txt
index 907e505b6309..a76b871f78a6 100644
--- a/tools/perf/Documentation/perf-report.txt
+++ b/tools/perf/Documentation/perf-report.txt
@@ -354,7 +354,8 @@ OPTIONS
         Path to objdump binary.
 
 --group::
-	Show event group information together.
+	Show event group information together. It forces group output also
+	if there are no groups defined in data file.
 
 --demangle::
 	Demangle symbol names to human readable form. It's enabled by default,
diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 8ef71669e7a0..1eedb1815c4c 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -938,6 +938,7 @@ int cmd_report(int argc, const char **argv)
 		"perf report [<options>]",
 		NULL
 	};
+	bool group_set = false;
 	struct report report = {
 		.tool = {
 			.sample		 = process_sample_event,
@@ -1057,7 +1058,7 @@ int cmd_report(int argc, const char **argv)
 		   "Specify disassembler style (e.g. -M intel for intel syntax)"),
 	OPT_BOOLEAN(0, "show-total-period", &symbol_conf.show_total_period,
 		    "Show a column with the sum of periods"),
-	OPT_BOOLEAN(0, "group", &symbol_conf.event_group,
+	OPT_BOOLEAN_SET(0, "group", &symbol_conf.event_group, &group_set,
 		    "Show event group information together"),
 	OPT_CALLBACK_NOOPT('b', "branch-stack", &branch_mode, "",
 		    "use branch records for per branch histogram filling",
@@ -1174,6 +1175,9 @@ int cmd_report(int argc, const char **argv)
 	has_br_stack = perf_header__has_feat(&session->header,
 					     HEADER_BRANCH_STACK);
 
+	if (group_set && !session->evlist->nr_groups)
+		perf_evlist__set_leader(session->evlist);
+
 	if (itrace_synth_opts.last_branch)
 		has_br_stack = true;
 
-- 
2.13.6