[PATCH 08/38] perf record: Add --index option for building index table

[Namhyung Kim <namhyung@kernel.org>]

The new --index option will create indexed data file which can be
processed by multiple threads parallelly.  It saves meta event and
sample data in separate files and merges them with an index table.

If there's an index table in the data file, the HEADER_DATA_INDEX
feature bit is set and session->header.index[0] will point to the meta
event area, and rest are sample data.  It'd look like below:

        +---------------------+
        |     file header     |
        |---------------------|
        |                     |
        |    meta events[0] <-+--+
        |                     |  |
        |---------------------|  |
        |                     |  |
        |    sample data[1] <-+--+
        |                     |  |
        |---------------------|  |
        |                     |  |
        |    sample data[2] <-|--+
        |                     |  |
        |---------------------|  |
        |         ...         | ...
        |---------------------|  |
        |     feature data    |  |
        |   (contains index) -+--+
        +---------------------+

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/Documentation/perf-record.txt |   4 +
 tools/perf/builtin-record.c              | 161 +++++++++++++++++++++++++++++--
 tools/perf/perf.h                        |   1 +
 tools/perf/util/session.c                |   1 +
 4 files changed, 158 insertions(+), 9 deletions(-)

diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index 355c4f5569b5..5476432c045f 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -250,6 +250,10 @@ is off by default.
 --running-time::
 Record running and enabled time for read events (:S)
 
+--index::
+Build an index table for sample data.  This will speed up perf report by
+parallel processing.
+
 SEE ALSO
 --------
 linkperf:perf-stat[1], linkperf:perf-list[1]
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 1bdf7e4a0a6f..ecf8e7293015 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -38,6 +38,7 @@ struct record {
 	struct record_opts	opts;
 	u64			bytes_written;
 	struct perf_data_file	file;
+	int			*fds;
 	struct perf_evlist	*evlist;
 	struct perf_session	*session;
 	const char		*progname;
@@ -47,9 +48,16 @@ struct record {
 	long			samples;
 };
 
-static int record__write(struct record *rec, void *bf, size_t size)
+static int record__write(struct record *rec, void *bf, size_t size, int idx)
 {
-	if (perf_data_file__write(rec->session->file, bf, size) < 0) {
+	int fd;
+
+	if (rec->fds && idx >= 0)
+		fd = rec->fds[idx];
+	else
+		fd = perf_data_file__fd(rec->session->file);
+
+	if (writen(fd, bf, size) < 0) {
 		pr_err("failed to write perf data, error: %m\n");
 		return -1;
 	}
@@ -64,7 +72,7 @@ static int process_synthesized_event(struct perf_tool *tool,
 				     struct machine *machine __maybe_unused)
 {
 	struct record *rec = container_of(tool, struct record, tool);
-	return record__write(rec, event, event->header.size);
+	return record__write(rec, event, event->header.size, -1);
 }
 
 static int record__mmap_read(struct record *rec, int idx)
@@ -89,7 +97,7 @@ static int record__mmap_read(struct record *rec, int idx)
 		size = md->mask + 1 - (old & md->mask);
 		old += size;
 
-		if (record__write(rec, buf, size) < 0) {
+		if (record__write(rec, buf, size, idx) < 0) {
 			rc = -1;
 			goto out;
 		}
@@ -99,7 +107,7 @@ static int record__mmap_read(struct record *rec, int idx)
 	size = head - old;
 	old += size;
 
-	if (record__write(rec, buf, size) < 0) {
+	if (record__write(rec, buf, size, idx) < 0) {
 		rc = -1;
 		goto out;
 	}
@@ -111,6 +119,113 @@ static int record__mmap_read(struct record *rec, int idx)
 	return rc;
 }
 
+#define INDEX_FILE_FMT  "%s.dir/perf.data.%d"
+
+static int record__create_index_files(struct record *rec, int nr_index)
+{
+	int i = 0;
+	int ret = -1;
+	char path[PATH_MAX];
+	struct perf_data_file *file = &rec->file;
+
+	/* +1 for header file itself */
+	nr_index++;
+
+	rec->fds = malloc(nr_index * sizeof(int));
+	if (rec->fds == NULL)
+		return -ENOMEM;
+
+	scnprintf(path, sizeof(path), "%s.dir", file->path);
+	if (mkdir(path, S_IRWXU) < 0)
+		goto out_err;
+
+	rec->fds[0] = perf_data_file__fd(file);
+
+	for (i = 1; i < nr_index; i++) {
+		scnprintf(path, sizeof(path), INDEX_FILE_FMT, file->path, i);
+		ret = open(path, O_RDWR|O_CREAT|O_TRUNC, S_IRUSR|S_IWUSR);
+		if (ret < 0)
+			goto out_err;
+
+		rec->fds[i] = ret;
+	}
+	return 0;
+
+out_err:
+	while (--i >= 1)
+		close(rec->fds[i]);
+	zfree(&rec->fds);
+
+	scnprintf(path, sizeof(path), "%s.dir", file->path);
+	rm_rf(path);
+
+	return ret;
+}
+
+static int record__merge_index_files(struct record *rec, int nr_index)
+{
+	int i;
+	int ret = -1;
+	u64 offset;
+	char path[PATH_MAX];
+	struct perf_file_section *idx;
+	struct perf_data_file *file = &rec->file;
+	struct perf_session *session = rec->session;
+	int output_fd = perf_data_file__fd(file);
+
+	/* +1 for header file itself */
+	nr_index++;
+
+	idx = calloc(nr_index, sizeof(*idx));
+	if (idx == NULL)
+		goto out_close;
+
+	offset = lseek(output_fd, 0, SEEK_END);
+
+	idx[0].offset = session->header.data_offset;
+	idx[0].size   = offset - idx[0].offset;
+
+	for (i = 1; i < nr_index; i++) {
+		struct stat stbuf;
+		int fd = rec->fds[i];
+
+		if (fstat(fd, &stbuf) < 0)
+			goto out_close;
+
+		idx[i].offset = offset;
+		idx[i].size   = stbuf.st_size;
+
+		offset += stbuf.st_size;
+	}
+
+	/* copy sample events */
+	for (i = 1; i < nr_index; i++) {
+		int fd = rec->fds[i];
+
+		if (idx[i].size == 0)
+			continue;
+
+		if (copyfile_offset(fd, 0, output_fd, idx[i].offset,
+				    idx[i].size) < 0)
+			goto out_close;
+	}
+
+	session->header.index = idx;
+	session->header.nr_index = nr_index;
+
+	ret = 0;
+
+out_close:
+	for (i = 1; i < nr_index; i++)
+		close(rec->fds[i]);
+
+	scnprintf(path, sizeof(path), "%s.dir", file->path);
+	rm_rf(path);
+
+	zfree(&rec->fds);
+	return ret;
+}
+
 static volatile int done = 0;
 static volatile int signr = -1;
 static volatile int child_finished = 0;
@@ -170,7 +285,7 @@ static int record__open(struct record *rec)
 	}
 
 	if (perf_evlist__mmap_track(evlist, opts->mmap_pages, false,
-				    false) < 0) {
+				    opts->index) < 0) {
 		if (errno == EPERM) {
 			pr_err("Permission error mapping pages.\n"
 			       "Consider increasing "
@@ -186,6 +301,12 @@ static int record__open(struct record *rec)
 		goto out;
 	}
 
+	if (opts->index) {
+		rc = record__create_index_files(rec, evlist->nr_mmaps);
+		if (rc < 0)
+			goto out;
+	}
+
 	session->evlist = evlist;
 	perf_session__set_id_hdr_size(session);
 out:
@@ -210,7 +331,8 @@ static int process_buildids(struct record *rec)
 	struct perf_data_file *file  = &rec->file;
 	struct perf_session *session = rec->session;
 
-	u64 size = lseek(perf_data_file__fd(file), 0, SEEK_CUR);
+	/* update file size after merging sample files with index */
+	u64 size = lseek(perf_data_file__fd(file), 0, SEEK_END);
 	if (size == 0)
 		return 0;
 
@@ -290,7 +412,8 @@ static int record__mmap_read_all(struct record *rec)
 	 * at least one event.
 	 */
 	if (bytes_written != rec->bytes_written)
-		rc = record__write(rec, &finished_round_event, sizeof(finished_round_event));
+		rc = record__write(rec, &finished_round_event,
+				   sizeof(finished_round_event), -1);
 
 out:
 	return rc;
@@ -313,7 +436,8 @@ static void record__init_features(struct record *rec)
 	if (!rec->opts.branch_stack)
 		perf_header__clear_feat(&session->header, HEADER_BRANCH_STACK);
 
-	perf_header__clear_feat(&session->header, HEADER_DATA_INDEX);
+	if (!rec->opts.index)
+		perf_header__clear_feat(&session->header, HEADER_DATA_INDEX);
 }
 
 static volatile int workload_exec_errno;
@@ -375,6 +499,11 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 		}
 	}
 
+	if (file->is_pipe && opts->index) {
+		pr_warning("Indexing is disabled for pipe output\n");
+		opts->index = false;
+	}
+
 	if (record__open(rec) != 0) {
 		err = -1;
 		goto out_child;
@@ -554,6 +683,9 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 	if (!err && !file->is_pipe) {
 		rec->session->header.data_size += rec->bytes_written;
 
+		if (rec->opts.index)
+			record__merge_index_files(rec, rec->evlist->nr_mmaps);
+
 		if (!rec->no_buildid)
 			process_buildids(rec);
 		perf_session__write_header(rec->session, rec->evlist, fd, true);
@@ -851,6 +983,8 @@ struct option __record_options[] = {
 		    "Sample machine registers on interrupt"),
 	OPT_BOOLEAN(0, "running-time", &record.opts.running_time,
 		    "Record running/enabled time of read (:S) events"),
+	OPT_BOOLEAN(0, "index", &record.opts.index,
+		    "make index for sample data to speed-up processing"),
 	OPT_END()
 };
 
@@ -900,6 +1034,15 @@ int cmd_record(int argc, const char **argv, const char *prefix __maybe_unused)
 		goto out_symbol_exit;
 	}
 
+	if (rec->opts.index) {
+		if (!rec->opts.sample_time) {
+			pr_err("Sample timestamp is required for indexing\n");
+			goto out_symbol_exit;
+		}
+
+		perf_evlist__add_dummy_tracking(rec->evlist);
+	}
+
 	if (rec->opts.target.tid && !rec->opts.no_inherit_set)
 		rec->opts.no_inherit = true;
 
diff --git a/tools/perf/perf.h b/tools/perf/perf.h
index 1caa70a4a9e1..a03552849399 100644
--- a/tools/perf/perf.h
+++ b/tools/perf/perf.h
@@ -54,6 +54,7 @@ struct record_opts {
 	bool	     period;
 	bool	     sample_intr_regs;
 	bool	     running_time;
+	bool	     index;
 	unsigned int freq;
 	unsigned int mmap_pages;
 	unsigned int user_freq;
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 00cd1ad427be..46761a39fbae 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -173,6 +173,7 @@ void perf_session__delete(struct perf_session *session)
 	machines__exit(&session->machines);
 	if (session->file)
 		perf_data_file__close(session->file);
+	free(session->header.index);
 	free(session);
 }
 
-- 
2.2.2