[PATCH v12 15/16] perf session: Load data directory files for analysis

[Alexey Bayduraev]

Load data directory files and provide basic raw dump and aggregated
analysis support of data directories in report mode, still with no
memory consumption optimizations.

READER_MAX_SIZE is chosen based on the results of measurements on
different machines on perf.data directory sizes >1GB. On machines
with big core count (192 cores) the difference between 1MB and 2MB
is about 4%. Other sizes (>2MB) are quite equal to 2MB.
On machines with small core count (4-24) there is no differences
between 1-16 MB sizes. So this constant is 2MB.

Suggested-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Acked-by: Namhyung Kim <namhyung@xxxxxxxxx>
Reviewed-by: Riccardo Mancini <rickyman7@xxxxxxxxx>
Tested-by: Riccardo Mancini <rickyman7@xxxxxxxxx>
Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@xxxxxxxxxxxxxxx>
---
 tools/perf/util/session.c | 133 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 133 insertions(+)

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index d8857d1b6d7c..1a8e3f106e95 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -2184,6 +2184,8 @@ struct reader {
 	u64		 file_pos;
 	u64		 file_offset;
 	u64		 head;
+	u64		 size;
+	bool		 done;
 	struct zstd_data   zstd_data;
 	struct decomp_data decomp_data;
 };
@@ -2301,6 +2303,7 @@ reader__read_event(struct reader *rd, struct perf_session *session,
 	if (skip)
 		size += skip;
 
+	rd->size += size;
 	rd->head += size;
 	rd->file_pos += size;
 
@@ -2409,6 +2412,133 @@ static int __perf_session__process_events(struct perf_session *session)
 	return err;
 }
 
+/*
+ * Processing 2 MB of data from each reader in sequence,
+ * because that's the way the ordered events sorting works
+ * most efficiently.
+ */
+#define READER_MAX_SIZE (2 * 1024 * 1024)
+
+/*
+ * This function reads, merge and process directory data.
+ * It assumens the version 1 of directory data, where each
+ * data file holds per-cpu data, already sorted by kernel.
+ */
+static int __perf_session__process_dir_events(struct perf_session *session)
+{
+	struct perf_data *data = session->data;
+	struct perf_tool *tool = session->tool;
+	int i, ret, readers, nr_readers;
+	struct ui_progress prog;
+	u64 total_size = perf_data__size(session->data);
+	struct reader *rd;
+
+	perf_tool__fill_defaults(tool);
+
+	ui_progress__init_size(&prog, total_size, "Sorting events...");
+
+	nr_readers = 1;
+	for (i = 0; i < data->dir.nr; i++) {
+		if (data->dir.files[i].size)
+			nr_readers++;
+	}
+
+	rd = zalloc(nr_readers * sizeof(struct reader));
+	if (!rd)
+		return -ENOMEM;
+
+	rd[0] = (struct reader) {
+		.fd		 = perf_data__fd(session->data),
+		.data_size	 = session->header.data_size,
+		.data_offset	 = session->header.data_offset,
+		.process	 = process_simple,
+		.in_place_update = session->data->in_place_update,
+	};
+	ret = reader__init(&rd[0], NULL);
+	if (ret)
+		goto out_err;
+	ret = reader__mmap(&rd[0], session);
+	if (ret)
+		goto out_err;
+	readers = 1;
+
+	for (i = 0; i < data->dir.nr; i++) {
+		if (!data->dir.files[i].size)
+			continue;
+		rd[readers] = (struct reader) {
+			.fd		 = data->dir.files[i].fd,
+			.data_size	 = data->dir.files[i].size,
+			.data_offset	 = 0,
+			.process	 = process_simple,
+			.in_place_update = session->data->in_place_update,
+		};
+		ret = reader__init(&rd[readers], NULL);
+		if (ret)
+			goto out_err;
+		ret = reader__mmap(&rd[readers], session);
+		if (ret)
+			goto out_err;
+		readers++;
+	}
+
+	i = 0;
+	while (readers) {
+		if (session_done())
+			break;
+
+		if (rd[i].done) {
+			i = (i + 1) % nr_readers;
+			continue;
+		}
+		if (reader__eof(&rd[i])) {
+			rd[i].done = true;
+			readers--;
+			continue;
+		}
+
+		session->active_decomp = &rd[i].decomp_data;
+		ret = reader__read_event(&rd[i], session, &prog);
+		if (ret < 0) {
+			goto out_err;
+		} else if (ret == READER_NODATA) {
+			ret = reader__mmap(&rd[i], session);
+			if (ret)
+				goto out_err;
+		}
+
+		if (rd[i].size >= READER_MAX_SIZE) {
+			rd[i].size = 0;
+			i = (i + 1) % nr_readers;
+		}
+	}
+
+	ret = ordered_events__flush(&session->ordered_events, OE_FLUSH__FINAL);
+	if (ret)
+		goto out_err;
+
+	ret = perf_session__flush_thread_stacks(session);
+out_err:
+	ui_progress__finish();
+
+	if (!tool->no_warn)
+		perf_session__warn_about_errors(session);
+
+	/*
+	 * We may switching perf.data output, make ordered_events
+	 * reusable.
+	 */
+	ordered_events__reinit(&session->ordered_events);
+
+	session->one_mmap = false;
+
+	session->active_decomp = &session->decomp_data;
+	for (i = 0; i < nr_readers; i++)
+		reader__release_decomp(&rd[i]);
+	zfree(&rd);
+
+	return ret;
+}
+
 int perf_session__process_events(struct perf_session *session)
 {
 	if (perf_session__register_idle_thread(session) < 0)
@@ -2417,6 +2547,9 @@ int perf_session__process_events(struct perf_session *session)
 	if (perf_data__is_pipe(session->data))
 		return __perf_session__process_pipe_events(session);
 
+	if (perf_data__is_dir(session->data))
+		return __perf_session__process_dir_events(session);
+
 	return __perf_session__process_events(session);
 }
 
-- 
2.19.0