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

Alexey Bayduraev
2021-11-23T14:10:10Z

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@kernel.org>
Acked-by: Namhyung Kim <namhyung@gmail.com>
Reviewed-by: Riccardo Mancini <rickyman7@gmail.com>
Tested-by: Riccardo Mancini <rickyman7@gmail.com>
Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
---
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