[RFC/PATCH 07/38] perf tools: Add HEADER_DATA_INDEX feature

[Namhyung Kim <namhyung@kernel.org>]

The HEADER_DATA_INDEX feature is to record index table for sample data
so that they can be processed by multiple thread concurrently.  Each
item is a struct perf_file_section which consists of an offset and size.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/builtin-record.c |  2 ++
 tools/perf/util/header.c    | 64 +++++++++++++++++++++++++++++++++++++++++++++
 tools/perf/util/header.h    |  3 +++
 3 files changed, 69 insertions(+)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 90b1237d2525..623984c81478 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -451,6 +451,8 @@ static void record__init_features(struct record *rec)
 
 	if (!rec->opts.full_auxtrace)
 		perf_header__clear_feat(&session->header, HEADER_AUXTRACE);
+
+	perf_header__clear_feat(&session->header, HEADER_DATA_INDEX);
 }
 
 static volatile int workload_exec_errno;
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 43838003c1a1..c357f7f47d32 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -868,6 +868,24 @@ static int write_auxtrace(int fd, struct perf_header *h,
 	return err;
 }
 
+static int write_data_index(int fd, struct perf_header *h,
+			    struct perf_evlist *evlist __maybe_unused)
+{
+	int ret;
+	unsigned i;
+
+	ret = do_write(fd, &h->nr_index, sizeof(h->nr_index));
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; i < h->nr_index; i++) {
+		ret = do_write(fd, &h->index[i], sizeof(*h->index));
+		if (ret < 0)
+			return ret;
+	}
+	return 0;
+}
+
 static void print_hostname(struct perf_header *ph, int fd __maybe_unused,
 			   FILE *fp)
 {
@@ -1221,6 +1239,12 @@ static void print_group_desc(struct perf_header *ph, int fd __maybe_unused,
 	}
 }
 
+static void print_data_index(struct perf_header *ph __maybe_unused,
+			     int fd __maybe_unused, FILE *fp)
+{
+	fprintf(fp, "# contains data index for parallel processing\n");
+}
+
 static int __event_process_build_id(struct build_id_event *bev,
 				    char *filename,
 				    struct perf_session *session)
@@ -1891,6 +1915,7 @@ out_free:
 	return ret;
 }
 
+
 static int process_auxtrace(struct perf_file_section *section,
 			    struct perf_header *ph, int fd,
 			    void *data __maybe_unused)
@@ -1907,6 +1932,44 @@ static int process_auxtrace(struct perf_file_section *section,
 	return err;
 }
 
+static int process_data_index(struct perf_file_section *section __maybe_unused,
+			      struct perf_header *ph, int fd,
+			      void *data __maybe_unused)
+{
+	ssize_t ret;
+	u64 nr_idx;
+	unsigned i;
+	struct perf_file_section *idx;
+
+	ret = readn(fd, &nr_idx, sizeof(nr_idx));
+	if (ret != sizeof(nr_idx))
+		return -1;
+
+	if (ph->needs_swap)
+		nr_idx = bswap_64(nr_idx);
+
+	idx = calloc(nr_idx, sizeof(*idx));
+	if (idx == NULL)
+		return -1;
+
+	for (i = 0; i < nr_idx; i++) {
+		ret = readn(fd, &idx[i], sizeof(*idx));
+		if (ret != sizeof(*idx)) {
+			free(idx);
+			return -1;
+		}
+
+		if (ph->needs_swap) {
+			idx[i].offset = bswap_64(idx[i].offset);
+			idx[i].size   = bswap_64(idx[i].size);
+		}
+	}
+
+	ph->index = idx;
+	ph->nr_index = nr_idx;
+	return 0;
+}
+
 struct feature_ops {
 	int (*write)(int fd, struct perf_header *h, struct perf_evlist *evlist);
 	void (*print)(struct perf_header *h, int fd, FILE *fp);
@@ -1948,6 +2011,7 @@ static const struct feature_ops feat_ops[HEADER_LAST_FEATURE] = {
 	FEAT_OPP(HEADER_PMU_MAPPINGS,	pmu_mappings),
 	FEAT_OPP(HEADER_GROUP_DESC,	group_desc),
 	FEAT_OPP(HEADER_AUXTRACE,	auxtrace),
+	FEAT_OPP(HEADER_DATA_INDEX,	data_index),
 };
 
 struct header_print_data {
diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
index 05f27cb6b7e3..add455a7abff 100644
--- a/tools/perf/util/header.h
+++ b/tools/perf/util/header.h
@@ -31,6 +31,7 @@ enum {
 	HEADER_PMU_MAPPINGS,
 	HEADER_GROUP_DESC,
 	HEADER_AUXTRACE,
+	HEADER_DATA_INDEX,
 	HEADER_LAST_FEATURE,
 	HEADER_FEAT_BITS	= 256,
 };
@@ -71,6 +72,8 @@ struct perf_header {
 	bool				needs_swap;
 	u64				data_offset;
 	u64				data_size;
+	struct perf_file_section	*index;
+	u64				nr_index;
 	u64				feat_offset;
 	DECLARE_BITMAP(adds_features, HEADER_FEAT_BITS);
 	struct perf_env 	env;
-- 
2.6.0