perf callchain: Setup callchain properly in pipe mode

Callchains are automatically initialized by checking on event's
sample_type. For pipe mode we need to put this check into attr event
code.

Moving the callchains setup code into callchain_param_setup function and
calling it from attr event process code.

This enables pipe output having callchains, like:

  # perf record -g -e 'raw_syscalls:sys_enter' true | perf script
  # perf record -g -e 'raw_syscalls:sys_enter' true | perf report

Committer notes:

We still need the next patch for the above output to work.
Reported-by: Paul Khuong <pvk@pvk.ca>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20200507095024.2789147-5-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-report.c

@@ -402,16 +402,7 @@ static int report__setup_sample_type(struct report *rep)
 		}
 	}
 
-	if (symbol_conf.use_callchain || symbol_conf.cumulate_callchain) {
-		if ((sample_type & PERF_SAMPLE_REGS_USER) &&
-		    (sample_type & PERF_SAMPLE_STACK_USER)) {
-			callchain_param.record_mode = CALLCHAIN_DWARF;
-			dwarf_callchain_users = true;
-		} else if (sample_type & PERF_SAMPLE_BRANCH_STACK)
-			callchain_param.record_mode = CALLCHAIN_LBR;
-		else
-			callchain_param.record_mode = CALLCHAIN_FP;
-	}
+	callchain_param_setup(sample_type);
 
 	if (rep->stitch_lbr && (callchain_param.record_mode != CALLCHAIN_LBR)) {
 		ui__warning("Can't find LBR callchain. Switch off --stitch-lbr.\n"
@@ -1089,6 +1080,26 @@ parse_percent_limit(const struct option *opt, const char *str,
 	return 0;
 }
 
+static int process_attr(struct perf_tool *tool __maybe_unused,
+			union perf_event *event,
+			struct evlist **pevlist)
+{
+	u64 sample_type;
+	int err;
+
+	err = perf_event__process_attr(tool, event, pevlist);
+	if (err)
+		return err;
+
+	/*
+	 * Check if we need to enable callchains based
+	 * on events sample_type.
+	 */
+	sample_type = perf_evlist__combined_sample_type(*pevlist);
+	callchain_param_setup(sample_type);
+	return 0;
+}
+
 int cmd_report(int argc, const char **argv)
 {
 	struct perf_session *session;
@@ -1119,7 +1130,7 @@ int cmd_report(int argc, const char **argv)
 			.fork		 = perf_event__process_fork,
 			.lost		 = perf_event__process_lost,
 			.read		 = process_read_event,
-			.attr		 = perf_event__process_attr,
+			.attr		 = process_attr,
 			.tracing_data	 = perf_event__process_tracing_data,
 			.build_id	 = perf_event__process_build_id,
 			.id_index	 = perf_event__process_id_index,

tools/perf/builtin-script.c

@@ -2085,6 +2085,7 @@ static int process_attr(struct perf_tool *tool, union perf_event *event,
 	struct perf_script *scr = container_of(tool, struct perf_script, tool);
 	struct evlist *evlist;
 	struct evsel *evsel, *pos;
+	u64 sample_type;
 	int err;
 	static struct evsel_script *es;
 
@@ -2119,10 +2120,19 @@ static int process_attr(struct perf_tool *tool, union perf_event *event,
 
 	set_print_ip_opts(&evsel->core.attr);
 
-	if (evsel->core.attr.sample_type)
+	if (evsel->core.attr.sample_type) {
 		err = perf_evsel__check_attr(evsel, scr->session);
+		if (err)
+			return err;
+	}
 
-	return err;
+	/*
+	 * Check if we need to enable callchains based
+	 * on events sample_type.
+	 */
+	sample_type = perf_evlist__combined_sample_type(evlist);
+	callchain_param_setup(sample_type);
+	return 0;
 }
 
 static int print_event_with_time(struct perf_tool *tool,

tools/perf/util/callchain.c

@@ -1599,3 +1599,17 @@ void callchain_cursor_reset(struct callchain_cursor *cursor)
 	for (node = cursor->first; node != NULL; node = node->next)
 		map__zput(node->ms.map);
 }
+
+void callchain_param_setup(u64 sample_type)
+{
+	if (symbol_conf.use_callchain || symbol_conf.cumulate_callchain) {
+		if ((sample_type & PERF_SAMPLE_REGS_USER) &&
+		    (sample_type & PERF_SAMPLE_STACK_USER)) {
+			callchain_param.record_mode = CALLCHAIN_DWARF;
+			dwarf_callchain_users = true;
+		} else if (sample_type & PERF_SAMPLE_BRANCH_STACK)
+			callchain_param.record_mode = CALLCHAIN_LBR;
+		else
+			callchain_param.record_mode = CALLCHAIN_FP;
+	}
+}

tools/perf/util/callchain.h

@@ -297,4 +297,5 @@ int callchain_branch_counts(struct callchain_root *root,
 			    u64 *branch_count, u64 *predicted_count,
 			    u64 *abort_count, u64 *cycles_count);
 
+void callchain_param_setup(u64 sample_type);
 #endif	/* __PERF_CALLCHAIN_H */