[PATCH v1 2/4] perf header: Allow tracing of attr events

[Ian Rogers <irogers@xxxxxxxxxx>]

In pipe mode attr events capture the perf_event_attr. Allow their
dumping as they normally start the file.

Before:
```
$ perf record -o - -a sleep 1 | perf script -D -i -
. ... raw event: size 272 bytes
.  0000:  40 00 00 00 00 00 10 01 00 00 00 00 88 00 00 00  @...............
.  0010:  00 00 00 00 00 00 00 00 a0 0f 00 00 00 00 00 00  ................
.  0020:  87 01 01 00 00 00 00 00 14 00 00 00 00 00 00 00  ................
.  0030:  01 84 05 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
.  0040:  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
.  0050:  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
.  0060:  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
.  0070:  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
.  0080:  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
.  0090:  91 08 00 00 00 00 00 00 92 08 00 00 00 00 00 00  ................
.  00a0:  93 08 00 00 00 00 00 00 94 08 00 00 00 00 00 00  ................
.  00b0:  95 08 00 00 00 00 00 00 96 08 00 00 00 00 00 00  ................
.  00c0:  97 08 00 00 00 00 00 00 98 08 00 00 00 00 00 00  ................
.  00d0:  99 08 00 00 00 00 00 00 9a 08 00 00 00 00 00 00  ................
.  00e0:  9b 08 00 00 00 00 00 00 9c 08 00 00 00 00 00 00  ................
.  00f0:  9d 08 00 00 00 00 00 00 9e 08 00 00 00 00 00 00  ................
.  0100:  9f 08 00 00 00 00 00 00 a0 08 00 00 00 00 00 00  ................

-1 -1 0 [0x110]: PERF_RECORD_ATTR
0x110@pipe [0x110]: event: 64
...
```

After:
```
$ perf record -o - -a sleep 1 | perf script -D -i -
0@pipe [0x110]: event: 64
.
. ... raw event: size 272 bytes
.  0000:  40 00 00 00 00 00 10 01 00 00 00 00 88 00 00 00  @...............
.  0010:  00 00 00 00 00 00 00 00 a0 0f 00 00 00 00 00 00  ................
.  0020:  87 01 01 00 00 00 00 00 14 00 00 00 00 00 00 00  ................
.  0030:  01 84 05 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
.  0040:  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
.  0050:  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
.  0060:  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
.  0070:  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
.  0080:  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
.  0090:  5c 08 00 00 00 00 00 00 5d 08 00 00 00 00 00 00  \.......].......
.  00a0:  5e 08 00 00 00 00 00 00 5f 08 00 00 00 00 00 00  ^......._.......
.  00b0:  60 08 00 00 00 00 00 00 61 08 00 00 00 00 00 00  `.......a.......
.  00c0:  62 08 00 00 00 00 00 00 63 08 00 00 00 00 00 00  b.......c.......
.  00d0:  64 08 00 00 00 00 00 00 65 08 00 00 00 00 00 00  d.......e.......
.  00e0:  66 08 00 00 00 00 00 00 67 08 00 00 00 00 00 00  f.......g.......
.  00f0:  68 08 00 00 00 00 00 00 69 08 00 00 00 00 00 00  h.......i.......
.  0100:  6a 08 00 00 00 00 00 00 6b 08 00 00 00 00 00 00  j.......k.......

-1 -1 0 [0x110]: PERF_RECORD_ATTR, type = 0 (PERF_TYPE_HARDWARE), size = 136, config = 0 (PERF_COUNT_HW_CPU_CYCLES), { sample_period, sample_freq } = 4000, sample_type = IP|TID|TIME|CPU|PERIOD|IDENTIFIER, read_format = ID|LOST, disabled = 1, freq = 1, precise_ip = 3, sample_id_all = 1
0x110@pipe [0x110]: event: 64
...
```

Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
 tools/perf/util/header.c | 8 ++++++++
 tools/perf/util/header.h | 1 +
 2 files changed, 9 insertions(+)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 84879d7fdffe..7798435ab5d3 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -4414,6 +4414,11 @@ size_t perf_event__fprintf_event_update(union perf_event *event, FILE *fp)
 	return ret;
 }
 
+size_t perf_event__fprintf_attr(union perf_event *event, FILE *fp)
+{
+	return perf_event_attr__fprintf(fp, &event->attr.attr, __desc_attr__fprintf, NULL);
+}
+
 int perf_event__process_attr(const struct perf_tool *tool __maybe_unused,
 			     union perf_event *event,
 			     struct evlist **pevlist)
@@ -4423,6 +4428,9 @@ int perf_event__process_attr(const struct perf_tool *tool __maybe_unused,
 	struct evsel *evsel;
 	struct evlist *evlist = *pevlist;
 
+	if (dump_trace)
+		perf_event__fprintf_attr(event, stdout);
+
 	if (evlist == NULL) {
 		*pevlist = evlist = evlist__new();
 		if (evlist == NULL)
diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
index 5201af6305f4..d16dfceccd74 100644
--- a/tools/perf/util/header.h
+++ b/tools/perf/util/header.h
@@ -175,6 +175,7 @@ int perf_event__process_attr(const struct perf_tool *tool, union perf_event *eve
 int perf_event__process_event_update(const struct perf_tool *tool,
 				     union perf_event *event,
 				     struct evlist **pevlist);
+size_t perf_event__fprintf_attr(union perf_event *event, FILE *fp);
 size_t perf_event__fprintf_event_update(union perf_event *event, FILE *fp);
 #ifdef HAVE_LIBTRACEEVENT
 int perf_event__process_tracing_data(struct perf_session *session,
-- 
2.50.0.rc0.604.gd4ff7b7c86-goog