[PATCH 28/46] perf record: Generate tracking events for process forked by perf

Wang Nan
2016-02-26T09:33:55Z

With 'perf record --switch-output' without -a, record__synthesize() in
record__switch_output() won't generate tracking events because there's
no thread_map in evlist. Which causes newly created perf.data doesn't
contain map and comm information.

This patch creates a fake thread_map and directly call
perf_event__synthesize_thread_map() for those events.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Signed-off-by: He Kuang <hekuang@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
tools/perf/builtin-record.c | 31 ++++++++++++++++++++++++++++++-
1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index b6feea2..a2de15b 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -530,6 +530,23 @@ record__finish_output(struct record *rec)
return;
}

+static int record__synthesize_workload(struct record *rec)
+{
+ struct {
+ struct thread_map map;
+ struct thread_map_data map_data;
+ } thread_map;
+
+ thread_map.map.nr = 1;
+ thread_map.map.map[0].pid = rec->evlist->workload.pid;
+ thread_map.map.map[0].comm = NULL;
+ return perf_event__synthesize_thread_map(&rec->tool, &thread_map.map,
+ process_synthesized_event,
+ &rec->session->machines.host,
+ rec->opts.sample_address,
+ rec->opts.proc_map_timeout);
+}
+
static int record__synthesize(struct record *rec);

static int
@@ -562,9 +579,21 @@ record__switch_output(struct record *rec, bool at_exit)
file->path, timestamp);

/* Output tracking events */
- if (!at_exit)
+ if (!at_exit) {
record__synthesize(rec);

+ /*
+ * In 'perf record --switch-output' without -a,
+ * record__synthesize() in record__switch_output() won't
+ * generate tracking events because there's no thread_map
+ * in evlist. Which causes newly created perf.data doesn't
+ * contain map and comm information.
+ * Create a fake thread_map and directly call
+ * perf_event__synthesize_thread_map() for those events.
+ */
+ if (target__none(&rec->opts.target))
+ record__synthesize_workload(rec);
+ }
return fd;
}

--
1.8.3.4