perf record: Display data size on pipe mode

Currently pipe mode doesn't set the file size and it results in a
misleading message of 0 data size at the end.  Although it might miss
some accounting for pipe header or more, just displaying the data size
would reduce the possible confusion.

Before:
  $ perf record -o- perf test -w noploop | perf report -i- -q --percent-limit=1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.000 MB - ]    <======  (here)
      99.58%  perf     perf                  [.] noploop

After:
  $ perf record -o- perf test -w noploop | perf report -i- -q --percent-limit=1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.229 MB - ]
      99.46%  perf     perf                  [.] noploop
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Reviewed-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20240112231340.779469-1-namhyung@kernel.org

tools/perf/builtin-record.c

@@ -1773,8 +1773,11 @@ record__finish_output(struct record *rec)
 	struct perf_data *data = &rec->data;
 	int fd = perf_data__fd(data);
 
-	if (data->is_pipe)
+	if (data->is_pipe) {
+		/* Just to display approx. size */
+		data->file.size = rec->bytes_written;
 		return;
+	}
 
 	rec->session->header.data_size += rec->bytes_written;
 	data->file.size = lseek(perf_data__fd(data), 0, SEEK_CUR);