[PATCH v5 7/7] perf diff: Support hot streams comparison

Jin Yao
2020-09-07T04:17:22Z

This patch enables perf-diff with "--stream" option.

"--stream": Enable hot streams comparison

Now let's see examples.

perf record -b ... Generate perf.data.old with branch data
perf record -b ... Generate perf.data with branch data
perf diff --stream

[ Matched hot streams ]

hot chain pair 1:
cycles: 1, hits: 27.77% cycles: 1, hits: 9.24%
--------------------------- --------------------------
main div.c:39 main div.c:39
main div.c:44 main div.c:44

hot chain pair 2:
cycles: 34, hits: 20.06% cycles: 27, hits: 16.98%
--------------------------- --------------------------
__random_r random_r.c:360 __random_r random_r.c:360
__random_r random_r.c:388 __random_r random_r.c:388
__random_r random_r.c:388 __random_r random_r.c:388
__random_r random_r.c:380 __random_r random_r.c:380
__random_r random_r.c:357 __random_r random_r.c:357
__random random.c:293 __random random.c:293
__random random.c:293 __random random.c:293
__random random.c:291 __random random.c:291
__random random.c:291 __random random.c:291
__random random.c:291 __random random.c:291
__random random.c:288 __random random.c:288
rand rand.c:27 rand rand.c:27
rand rand.c:26 rand rand.c:26
rand@plt rand@plt
rand@plt rand@plt
compute_flag div.c:25 compute_flag div.c:25
compute_flag div.c:22 compute_flag div.c:22
main div.c:40 main div.c:40
main div.c:40 main div.c:40
main div.c:39 main div.c:39

hot chain pair 3:
cycles: 9, hits: 4.48% cycles: 6, hits: 4.51%
--------------------------- --------------------------
__random_r random_r.c:360 __random_r random_r.c:360
__random_r random_r.c:388 __random_r random_r.c:388
__random_r random_r.c:388 __random_r random_r.c:388
__random_r random_r.c:380 __random_r random_r.c:380

[ Hot streams in old perf data only ]

hot chain 1:
cycles: 18, hits: 6.75%
--------------------------
__random_r random_r.c:360
__random_r random_r.c:388
__random_r random_r.c:388
__random_r random_r.c:380
__random_r random_r.c:357
__random random.c:293
__random random.c:293
__random random.c:291
__random random.c:291
__random random.c:291
__random random.c:288
rand rand.c:27
rand rand.c:26
rand@plt
rand@plt
compute_flag div.c:25
compute_flag div.c:22
main div.c:40

hot chain 2:
cycles: 29, hits: 2.78%
--------------------------
compute_flag div.c:22
main div.c:40
main div.c:40
main div.c:39

[ Hot streams in new perf data only ]

hot chain 1:
cycles: 4, hits: 4.54%
--------------------------
main div.c:42
compute_flag div.c:28

hot chain 2:
cycles: 5, hits: 3.51%
--------------------------
main div.c:39
main div.c:44
main div.c:42
compute_flag div.c:28

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
---
v5:
- Remove enum stream_type
- Rebase to perf/core

v4:
- Remove the "--before" and "--after" options since they are for
source line based comparison. In this patchset, we will not
support source line based comparison.

tools/perf/Documentation/perf-diff.txt | 4 +
tools/perf/builtin-diff.c | 133 ++++++++++++++++++++++---
2 files changed, 124 insertions(+), 13 deletions(-)

diff --git a/tools/perf/Documentation/perf-diff.txt b/tools/perf/Documentation/perf-diff.txt
index d5cc15e651cf..5e2e4b7d62ec 100644
--- a/tools/perf/Documentation/perf-diff.txt
+++ b/tools/perf/Documentation/perf-diff.txt
@@ -177,6 +177,10 @@ OPTIONS
--tid=::
Only diff samples for given thread ID (comma separated list).

+--stream::
+ Enable hot streams comparison. Stream can be a callchain which is
+ aggregated by the branch records from samples.
+
COMPARISON
----------
The comparison is governed by the baseline file. The baseline perf.data
diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index c37a78677955..6a6b52a0a49b 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -23,6 +23,7 @@
#include "util/time-utils.h"
#include "util/annotate.h"
#include "util/map.h"
+#include "util/stream.h"
#include <linux/err.h>
#include <linux/zalloc.h>
#include <subcmd/pager.h>
@@ -40,6 +41,7 @@ struct perf_diff {
int range_size;
int range_num;
bool has_br_stack;
+ bool stream;
};

/* Diff command specific HPP columns. */
@@ -69,6 +71,8 @@ struct data__file {
struct perf_data data;
int idx;
struct hists *hists;
+ struct evsel_streams *evsel_streams;
+ int nr_evsel_streams;
struct diff_hpp_fmt fmt[PERF_HPP_DIFF__MAX_INDEX];
};

@@ -104,6 +108,7 @@ enum {
COMPUTE_DELTA_ABS,
COMPUTE_CYCLES,
COMPUTE_MAX,
+ COMPUTE_STREAM, /* After COMPUTE_MAX to avoid use current compute arrays */
};

const char *compute_names[COMPUTE_MAX] = {
@@ -387,6 +392,11 @@ static int diff__process_sample_event(struct perf_tool *tool,
struct perf_diff *pdiff = container_of(tool, struct perf_diff, tool);
struct addr_location al;
struct hists *hists = evsel__hists(evsel);
+ struct hist_entry_iter iter = {
+ .evsel = evsel,
+ .sample = sample,
+ .ops = &hist_iter_normal,
+ };
int ret = -1;

if (perf_time__ranges_skip_sample(pdiff->ptime_range, pdiff->range_num,
@@ -405,14 +415,8 @@ static int diff__process_sample_event(struct perf_tool *tool,
goto out_put;
}

- if (compute != COMPUTE_CYCLES) {
- if (!hists__add_entry(hists, &al, NULL, NULL, NULL, sample,
- true)) {
- pr_warning("problem incrementing symbol period, "
- "skipping event\n");
- goto out_put;
- }
- } else {
+ switch (compute) {
+ case COMPUTE_CYCLES:
if (!hists__add_entry_ops(hists, &block_hist_ops, &al, NULL,
NULL, NULL, sample, true)) {
pr_warning("problem incrementing symbol period, "
@@ -421,6 +425,23 @@ static int diff__process_sample_event(struct perf_tool *tool,
}

hist__account_cycles(sample->branch_stack, &al, sample, false);
+ break;
+
+ case COMPUTE_STREAM:
+ if (hist_entry_iter__add(&iter, &al, PERF_MAX_STACK_DEPTH,
+ NULL)) {
+ pr_debug("problem adding hist entry, skipping event\n");
+ goto out_put;
+ }
+ break;
+
+ default:
+ if (!hists__add_entry(hists, &al, NULL, NULL, NULL, sample,
+ true)) {
+ pr_warning("problem incrementing symbol period, "
+ "skipping event\n");
+ goto out_put;
+ }
}

/*
@@ -1058,6 +1079,50 @@ static void data_process(void)
}
}

+static int process_base_stream(struct data__file *data_base,
+ struct data__file *data_pair,
+ const char *title __maybe_unused)
+{
+ struct evlist *evlist_base = data_base->session->evlist;
+ struct evlist *evlist_pair = data_pair->session->evlist;
+ struct evsel *evsel_base, *evsel_pair;
+ struct evsel_streams *es_base, *es_pair;
+
+ evlist__for_each_entry(evlist_base, evsel_base) {
+ evsel_pair = evsel_match(evsel_base, evlist_pair);
+ if (!evsel_pair)
+ continue;
+
+ es_base = evsel_streams_get(data_base->evsel_streams,
+ data_base->nr_evsel_streams,
+ evsel_base->idx);
+ if (!es_base)
+ return -1;
+
+ es_pair = evsel_streams_get(data_pair->evsel_streams,
+ data_pair->nr_evsel_streams,
+ evsel_pair->idx);
+ if (!es_pair)
+ return -1;
+
+ match_evsel_streams(es_base, es_pair);
+ evsel_streams_report(es_base, es_pair);
+ }
+
+ return 0;
+}
+
+static void stream_process(void)
+{
+ /*
+ * Stream comparison only supports two data files.
+ * perf.data.old and perf.data. data__files[0] is perf.data.old,
+ * data__files[1] is perf.data.
+ */
+ process_base_stream(&data__files[0], &data__files[1],
+ "# Output based on old perf data:\n#\n");
+}
+
static void data__free(struct data__file *d)
{
int col;
@@ -1171,6 +1236,18 @@ static int check_file_brstack(void)
return 0;
}

+static struct evsel_streams *create_evsel_streams(struct evlist *evlist,
+ int nr_streams_max,
+ int *nr_evsel_streams)
+{
+ struct evsel_streams *es;
+
+ es = perf_evlist__create_streams(evlist, nr_streams_max);
+ *nr_evsel_streams = evlist->core.nr_entries;
+
+ return es;
+}
+
static int __cmd_diff(void)
{
struct data__file *d;
@@ -1215,9 +1292,21 @@ static int __cmd_diff(void)

if (pdiff.ptime_range)
zfree(&pdiff.ptime_range);
+
+ if (compute == COMPUTE_STREAM) {
+ d->evsel_streams = create_evsel_streams(
+ d->session->evlist,
+ 5,
+ &d->nr_evsel_streams);
+ if (!d->evsel_streams)
+ goto out_delete;
+ }
}

- data_process();
+ if (compute == COMPUTE_STREAM)
+ stream_process();
+ else
+ data_process();

out_delete:
data__for_each_file(i, d) {
@@ -1287,6 +1376,8 @@ static const struct option options[] = {
"only consider symbols in these pids"),
OPT_STRING(0, "tid", &symbol_conf.tid_list_str, "tid[,tid...]",
"only consider symbols in these tids"),
+ OPT_BOOLEAN(0, "stream", &pdiff.stream,
+ "Enable hot streams comparison."),
OPT_END()
};

@@ -1850,6 +1941,9 @@ int cmd_diff(int argc, const char **argv)
if (quiet)
perf_quiet_option();

+ if (pdiff.stream)
+ compute = COMPUTE_STREAM;
+
symbol__annotation_init();

if (symbol__init(NULL) < 0)
@@ -1861,13 +1955,26 @@ int cmd_diff(int argc, const char **argv)
if (check_file_brstack() < 0)
return -1;

- if (compute == COMPUTE_CYCLES && !pdiff.has_br_stack)
+ if ((compute == COMPUTE_CYCLES || compute == COMPUTE_STREAM)
+ && !pdiff.has_br_stack) {
return -1;
+ }

- if (ui_init() < 0)
- return -1;
+ if (compute == COMPUTE_STREAM) {
+ symbol_conf.show_branchflag_count = true;
+ symbol_conf.disable_add2line_warn = true;
+ callchain_param.mode = CHAIN_FLAT;
+ callchain_param.key = CCKEY_SRCLINE;
+ callchain_param.branch_callstack = 1;
+ symbol_conf.use_callchain = true;
+ callchain_register_param(&callchain_param);
+ sort_order = "srcline,symbol,dso";
+ } else {
+ if (ui_init() < 0)
+ return -1;

- sort__mode = SORT_MODE__DIFF;
+ sort__mode = SORT_MODE__DIFF;
+ }

if (setup_sorting(NULL) < 0)
usage_with_options(diff_usage, options);
--
2.17.1