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 <[e-mail]>
Reviewed-by: Ian Rogers <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

tools/perf/builtin-record.c

···
 	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);