3 files changed, 78 insertions, 56 deletions

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index fc3709cba13..f0467ff0d8a 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -574,11 +574,11 @@ static int __cmd_record(int argc, const char **argv)
 		header = perf_header__new();
 
 	if (raw_samples) {
-		perf_header__set_trace_info();
+		perf_header__feat_trace_info(header);
 	} else {
 		for (i = 0; i < nr_counters; i++) {
 			if (attrs[i].sample_type & PERF_SAMPLE_RAW) {
-				perf_header__set_trace_info();
+				perf_header__feat_trace_info(header);
 				break;
 			}
 		}
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 9aae360c0f2..171d51b6f35 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -8,6 +8,8 @@
 #include "../perf.h"
 #include "trace-event.h"
 
+#include <linux/bitmap.h>
+
 /*
  * Create new perf.data header attribute:
  */
@@ -48,25 +50,17 @@ void perf_header_attr__add_id(struct perf_header_attr *self, u64 id)
  */
 struct perf_header *perf_header__new(void)
 {
-	struct perf_header *self = malloc(sizeof(*self));
+	struct perf_header *self = calloc(sizeof(*self), 1);
 
 	if (!self)
 		die("nomem");
 
-	self->frozen = 0;
-
-	self->attrs = 0;
 	self->size = 1;
 	self->attr = malloc(sizeof(void *));
 
 	if (!self->attr)
 		die("nomem");
 
-	self->data_offset = 0;
-	self->data_size = 0;
-	self->trace_info_offset = 0;
-	self->trace_info_size = 0;
-
 	return self;
 }
 
@@ -149,14 +143,12 @@ struct perf_file_header {
 	struct perf_file_section	attrs;
 	struct perf_file_section	data;
 	struct perf_file_section	event_types;
-	struct perf_file_section	trace_info;
+	feat_mask_t			adds_features;
 };
 
-static int trace_info;
-
-void perf_header__set_trace_info(void)
+void perf_header__feat_trace_info(struct perf_header *header)
 {
-	trace_info = 1;
+	set_bit(HEADER_TRACE_INFO, perf_header__adds_mask(header));
 }
 
 static void do_write(int fd, void *buf, size_t size)
@@ -172,6 +164,32 @@ static void do_write(int fd, void *buf, size_t size)
 	}
 }
 
+static void perf_header__adds_write(struct perf_header *self, int fd)
+{
+	struct perf_file_section trace_sec;
+	u64 cur_offset = lseek(fd, 0, SEEK_CUR);
+	unsigned long *feat_mask = perf_header__adds_mask(self);
+
+	if (test_bit(HEADER_TRACE_INFO, feat_mask)) {
+		/* Write trace info */
+		trace_sec.offset = lseek(fd, sizeof(trace_sec), SEEK_CUR);
+		read_tracing_data(fd, attrs, nr_counters);
+		trace_sec.size = lseek(fd, 0, SEEK_CUR) - trace_sec.offset;
+
+		/* Write trace info headers */
+		lseek(fd, cur_offset, SEEK_SET);
+		do_write(fd, &trace_sec, sizeof(trace_sec));
+
+		/*
+		 * Update cur_offset. So that other (future)
+		 * features can set their own infos in this place. But if we are
+		 * the only feature, at least that seeks to the place the data
+		 * should begin.
+		 */
+		cur_offset = lseek(fd, trace_sec.offset + trace_sec.size, SEEK_SET);
+	}
+};
+
 void perf_header__write(struct perf_header *self, int fd)
 {
 	struct perf_file_header f_header;
@@ -210,23 +228,7 @@ void perf_header__write(struct perf_header *self, int fd)
 	if (events)
 		do_write(fd, events, self->event_size);
 
-	if (trace_info) {
-		static int trace_info_written;
-
-		/*
-		 * Write it only once
-		 */
-		if (!trace_info_written) {
-			self->trace_info_offset = lseek(fd, 0, SEEK_CUR);
-			read_tracing_data(fd, attrs, nr_counters);
-			self->trace_info_size = lseek(fd, 0, SEEK_CUR) -
-						self->trace_info_offset;
-			trace_info_written = 1;
-		} else {
-			lseek(fd, self->trace_info_offset +
-				self->trace_info_size, SEEK_SET);
-		}
-	}
+	perf_header__adds_write(self, fd);
 
 	self->data_offset = lseek(fd, 0, SEEK_CUR);
 
@@ -246,12 +248,10 @@ void perf_header__write(struct perf_header *self, int fd)
 			.offset = self->event_offset,
 			.size	= self->event_size,
 		},
-		.trace_info = {
-			.offset = self->trace_info_offset,
-			.size = self->trace_info_size,
-		},
 	};
 
+	memcpy(&f_header.adds_features, &self->adds_features, sizeof(feat_mask_t));
+
 	lseek(fd, 0, SEEK_SET);
 	do_write(fd, &f_header, sizeof(f_header));
 	lseek(fd, self->data_offset + self->data_size, SEEK_SET);
@@ -274,6 +274,20 @@ static void do_read(int fd, void *buf, size_t size)
 	}
 }
 
+static void perf_header__adds_read(struct perf_header *self, int fd)
+{
+	const unsigned long *feat_mask = perf_header__adds_mask(self);
+
+	if (test_bit(HEADER_TRACE_INFO, feat_mask)) {
+		struct perf_file_section trace_sec;
+
+		do_read(fd, &trace_sec, sizeof(trace_sec));
+		lseek(fd, trace_sec.offset, SEEK_SET);
+		trace_report(fd);
+		lseek(fd, trace_sec.offset + trace_sec.size, SEEK_SET);
+	}
+};
+
 struct perf_header *perf_header__read(int fd)
 {
 	struct perf_header	*self = perf_header__new();
@@ -292,9 +306,11 @@ struct perf_header *perf_header__read(int fd)
 
 	if (f_header.size != sizeof(f_header)) {
 		/* Support the previous format */
-		if (f_header.size == offsetof(typeof(f_header), trace_info))
-			f_header.trace_info.size = 0;
-		else
+		if (f_header.size == offsetof(typeof(f_header), adds_features)) {
+			unsigned long *mask = (unsigned long *)(void *)
+					&f_header.adds_features;
+			bitmap_zero(mask, HEADER_FEAT_BITS);
+		} else
 			die("incompatible file format");
 	}
 	nr_attrs = f_header.attrs.size / sizeof(f_attr);
@@ -330,13 +346,9 @@ struct perf_header *perf_header__read(int fd)
 		event_count =  f_header.event_types.size / sizeof(struct perf_trace_event_type);
 	}
 
-	self->trace_info_offset = f_header.trace_info.offset;
-	self->trace_info_size = f_header.trace_info.size;
+	memcpy(&self->adds_features, &f_header.adds_features, sizeof(feat_mask_t));
 
-	if (self->trace_info_size) {
-		lseek(fd, self->trace_info_offset, SEEK_SET);
-		trace_report(fd);
-	}
+	perf_header__adds_read(self, fd);
 
 	self->event_offset = f_header.event_types.offset;
 	self->event_size   = f_header.event_types.size;
diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
index 30aee5160dc..0eb4a9126b7 100644
--- a/tools/perf/util/header.h
+++ b/tools/perf/util/header.h
@@ -12,19 +12,29 @@ struct perf_header_attr {
 	off_t id_offset;
 };
 
+#define HEADER_TRACE_INFO			1
+
+#define HEADER_FEAT_BITS			256
+
+typedef	typeof(u64[HEADER_FEAT_BITS / 8])	feat_mask_t;
+
 struct perf_header {
-	int frozen;
-	int attrs, size;
+	int			frozen;
+	int			attrs, size;
 	struct perf_header_attr **attr;
-	s64 attr_offset;
-	u64 data_offset;
-	u64 data_size;
-	u64 event_offset;
-	u64 event_size;
-	u64 trace_info_offset;
-	u64 trace_info_size;
+	s64			attr_offset;
+	u64			data_offset;
+	u64			data_size;
+	u64			event_offset;
+	u64			event_size;
+	feat_mask_t		adds_features;
 };
 
+static inline unsigned long *perf_header__adds_mask(struct perf_header *self)
+{
+	return (unsigned long *)(void *)&self->adds_features;
+}
+
 struct perf_header *perf_header__read(int fd);
 void perf_header__write(struct perf_header *self, int fd);
 
@@ -42,7 +52,7 @@ void perf_header_attr__add_id(struct perf_header_attr *self, u64 id);
 u64 perf_header__sample_type(struct perf_header *header);
 struct perf_event_attr *
 perf_header__find_attr(u64 id, struct perf_header *header);
-void perf_header__set_trace_info(void);
+void perf_header__feat_trace_info(struct perf_header *header);
 
 struct perf_header *perf_header__new(void);