perf annotate: Add function header to --stdio2

Commit-ID:  864298f224f20fb7b981b05dd0f77315c75eb189
Gitweb:     https://git.kernel.org/tip/864298f224f20fb7b981b05dd0f77315c75eb189
Author:     Arnaldo Carvalho de Melo <[email protected]>
AuthorDate: Fri, 16 Mar 2018 15:17:23 -0300
Committer:  Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Wed, 21 Mar 2018 12:53:41 -0300

perf annotate: Add function header to --stdio2

  # perf annotate --stdio2 _raw_spin_lock_irqsave
  _raw_spin_lock_irqsave() /lib/modules/4.16.0-rc4/build/vmlinux
  Event: anon group { cycles, instructions }

    0.00   3.17      → callq  __fentry__
    0.00   7.94        push   %rbx
    7.69  36.51      → callq  __page_file_index
                       mov    %rax,%rbx
    7.69   3.17      → callq  *ffffffff82225cd0
                       xor    %eax,%eax
                       mov    $0x1,%edx

80.77 49.21 lock cmpxchg %edx,(%rdi)
test %eax,%eax
↓ jne 2b
3.85 0.00 mov %rbx,%rax
pop %rbx
← retq
2b: mov %eax,%esi
→ callq queued_spin_lock_slowpath
mov %rbx,%rax
pop %rbx
← retq
#

---
 tools/perf/util/annotate.c | 8 ++++++++
 1 file changed, 8 insertions(+)

index ea83b9754ab0..7a6a85f9fea6 100644
@@ -2244,6 +2244,8 @@ int symbol__tty_annotate2(struct symbol *sym, struct map *map,
 	struct dso *dso = map->dso;
 	struct rb_root source_line = RB_ROOT;
 	struct annotation_options opts = annotation__default_options;
+	const char *ev_name = perf_evsel__name(evsel);
+	char buf[1024];
 
 	if (symbol__annotate2(sym, map, evsel, &opts, NULL) < 0)
 		return -1;

@@ -2254,6 +2256,12 @@ int symbol__tty_annotate2(struct symbol *sym, struct map *map,
 		print_summary(&source_line, dso->long_name);
 	}
 
+	if (perf_evsel__is_group_event(evsel)) {
+		perf_evsel__group_desc(evsel, buf, sizeof(buf));
+		ev_name = buf;
+	}
+
+	fprintf(stdout, "%s() %s\nEvent: %s\n\n", sym->name, dso->long_name, ev_name);
 	symbol__annotate_fprintf2(sym, stdout);
 
 	annotated_source__purge(symbol__annotation(sym)->src);