[PATCH 39/53] perf record: Re-synthesize tracking events after output switching

Tracking events describe kernel and threads. They are generated by
reading /proc/kallsyms, /proc/*/maps and /proc/*/task/* during
initialization of 'perf record', serialized into event sequences and put
at the head of 'perf.data'. In case of output switching, each output
file should contain those events.

This patch calls record__synthesize() during output switching, so the
event sequences described above can be collected again.

Signed-off-by: Wang Nan <redacted>
Signed-off-by: He Kuang <redacted>
Cc: Arnaldo Carvalho de Melo <redacted>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <redacted>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <redacted>
Cc: pi3orama@163.com
---
 tools/perf/builtin-record.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 790361b..5305a30 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c

@@ -525,6 +525,8 @@ record__finish_output(struct record *rec)
 	return;
 }
 
+static int record__synthesize(struct record *rec);
+
 static int
 record__switch_output(struct record *rec, bool at_exit)
 {

@@ -553,6 +555,15 @@ record__switch_output(struct record *rec, bool at_exit)
 	if (!quiet)
 		fprintf(stderr, "[ perf record: Dump %s.%s ]\n",
 			file->path, timestamp);
+
+	/* Reinit machine */
+	if (!at_exit) {
+		machines__exit(&rec->session->machines);
+		machines__init(&rec->session->machines);
+		perf_session__create_kernel_maps(rec->session);
+		perf_session__set_id_hdr_size(rec->session);
+		record__synthesize(rec);
+	}
 	return fd;
 }
 

-- 
1.8.3.4