[RFC PATCH v2 4/5] perf data: Add --to-trace-dat option for converting perf.data tracepoint events into trace.dat format

[Tanushree Shah <tshah@linux.ibm.com>]

Add new command-line option to perf data convert for generating
trace.dat output files.

The --to-trace-dat option:
- Accepts output filename for trace.dat format
- Mutually exclusive with --to-ctf and --to-json
- Calls trace_convert__perf2dat() to perform conversion

Usage:
  $ perf record -e sched:* -a sleep 1
  $ perf data convert --to-trace-dat=trace.dat
  $ trace-cmd report trace.dat

Document the new option in Documentation/perf-data.txt alongside
the existing --to-ctf and --to-json entries.

Signed-off-by: Tanushree Shah <tshah@linux.ibm.com>
---
 tools/perf/Documentation/perf-data.txt |  7 +++++
 tools/perf/builtin-data.c              | 40 ++++++++++++++++++++++++--
 tools/perf/util/trace-dat.c            |  3 ++
 3 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/tools/perf/Documentation/perf-data.txt b/tools/perf/Documentation/perf-data.txt
index 20f178d61ed7..578ba6357183 100644
--- a/tools/perf/Documentation/perf-data.txt
+++ b/tools/perf/Documentation/perf-data.txt
@@ -30,6 +30,13 @@ OPTIONS for 'convert'
 --to-json::
 	Triggers JSON conversion. Specify the JSON filename to output.
 
+--to-trace-dat::
+	Triggers trace.dat conversion. Converts perf.data tracepoint events
+	to trace.dat format v7, compatible with trace-cmd and KernelShark.
+	Only PERF_TYPE_TRACEPOINT events are converted. Specify the
+	trace.dat filename to output. Requires libtraceevent support.
+	Mutually exclusive with --to-ctf and --to-json.
+
 --tod::
 	Convert time to wall clock time.
 
diff --git a/tools/perf/builtin-data.c b/tools/perf/builtin-data.c
index 4c08ccb8c06b..194537503ba9 100644
--- a/tools/perf/builtin-data.c
+++ b/tools/perf/builtin-data.c
@@ -30,6 +30,11 @@ static const char *data_usage[] = {
 
 static const char *to_json;
 static const char *to_ctf;
+
+#ifdef HAVE_LIBTRACEEVENT
+static const char *trace_dat_output;
+#endif
+
 static struct perf_data_convert_opts opts = {
 	.force = false,
 	.all = false,
@@ -48,6 +53,10 @@ static const struct option data_options[] = {
 		OPT_BOOLEAN(0, "all", &opts.all, "Convert all events"),
 		OPT_STRING(0, "time", &opts.time_str, "str",
 			   "Time span of interest (start,stop)"),
+#ifdef HAVE_LIBTRACEEVENT
+		OPT_STRING(0, "to-trace-dat", &trace_dat_output,
+			   "file", "Convert to trace.dat format using perf.data tracepoints"),
+#endif
 		OPT_END()
 	};
 
@@ -65,16 +74,43 @@ static int cmd_data_convert(int argc, const char **argv)
 		pr_err("You cannot specify both --to-ctf and --to-json.\n");
 		return -1;
 	}
+#ifdef HAVE_LIBTRACEEVENT
+	if (trace_dat_output && (to_json || to_ctf)) {
+		pr_err("You cannot specify --to-trace-dat with --to-ctf or --to-json.\n");
+		return -1;
+	}
+#endif
+
 #ifdef HAVE_LIBBABELTRACE_SUPPORT
+	#ifdef HAVE_LIBTRACEEVENT
+	if (!to_json && !to_ctf && !trace_dat_output) {
+		pr_err("You must specify one of --to-ctf, --to-json, or --to-trace-dat.\n");
+		return -1;
+	}
+	#else
 	if (!to_json && !to_ctf) {
 		pr_err("You must specify one of --to-ctf or --to-json.\n");
 		return -1;
 	}
+	#endif
 #else
+	#ifdef HAVE_LIBTRACEEVENT
+	if (!to_json && !trace_dat_output) {
+		pr_err("You must specify --to-json or --to-trace-dat.\n");
+		return -1;
+	}
+	#else
 	if (!to_json) {
 		pr_err("You must specify --to-json.\n");
-	return -1;
-}
+		return -1;
+	}
+	#endif
+#endif
+
+#ifdef HAVE_LIBTRACEEVENT
+	if (trace_dat_output)
+		return trace_convert__perf2dat(input_name ? input_name : "perf.data",
+					       trace_dat_output, &opts);
 #endif
 
 	if (to_json)
diff --git a/tools/perf/util/trace-dat.c b/tools/perf/util/trace-dat.c
index f71e03716e27..5598496c9a61 100644
--- a/tools/perf/util/trace-dat.c
+++ b/tools/perf/util/trace-dat.c
@@ -861,6 +861,9 @@ void trace_dat__free_cpu_buffers(void)
 	for (cpu = 0; cpu < trace_dat_nr_cpus; cpu++) {
 		int i;
 
+		if (!trace_cpu_data[cpu].events)
+			continue;
+
 		for (i = 0; i < trace_cpu_data[cpu].count; i++)
 			free(trace_cpu_data[cpu].events[i].raw);
 		free(trace_cpu_data[cpu].events);
-- 
2.47.3