[PATCH v2 07/14] perf diff: Support hot streams comparison

Jin Yao
2020-03-13T07:12:15Z

This patch enables perf-diff with "--stream", "--before" and "--after"
options.

"--stream": Enable hot streams comparison
"--before": Source code directory corresponding to perf.data.old
"--after" : Source code directory corresponding to perf.data

Let's see two 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 chains between old perf data and new perf data ]

hot chain pair 1:
cycles: 1, hits: 26.80% cycles: 1, hits: 27.30%
--------------------------- --------------------------
main div.c:39 main div.c:39
main div.c:44 main div.c:44

hot chain pair 2:
cycles: 35, hits: 21.43% cycles: 33, hits: 19.37%
--------------------------- --------------------------
__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: 18, hits: 6.10% cycles: 19, hits: 6.51%
--------------------------- --------------------------
__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
__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

hot chain pair 4:
cycles: 9, hits: 5.95% cycles: 8, hits: 5.03%
--------------------------- --------------------------
__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 chains in old perf data but source line changed (*) in new perf data ]

[ Hot chains in old perf data only ]

hot chain 1:
cycles: 2, hits: 4.08%
--------------------------
main div.c:42
compute_flag div.c:28

[ Hot chains in new perf data only ]

hot chain 1:
cycles: 36, hits: 3.36%
--------------------------
__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
main div.c:40

If we enable the source line comparison, the output might be different.

perf diff --stream --before ./before --after ./after

[ Matched hot chains between old perf data and new perf data) ]

hot chain pair 1:
cycles: 18, hits: 6.10% cycles: 19, hits: 6.51%
--------------------------- --------------------------
__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
__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

hot chain pair 2:
cycles: 9, hits: 5.95% cycles: 8, hits: 5.03%
--------------------------- --------------------------
__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 chains in old perf data but source line changed (*) in new perf data ]

hot chain pair 1:
cycles: 1, hits: 26.80% cycles: 1, hits: 27.30%
--------------------------- --------------------------
main div.c:39 main div.c:39*
main div.c:44 main div.c:44

hot chain pair 2:
cycles: 35, hits: 21.43% cycles: 33, hits: 19.37%
--------------------------- --------------------------
__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 chains in old perf data only ]

hot chain 1:
cycles: 2, hits: 4.08%
--------------------------
main div.c:42
compute_flag div.c:28

[ Hot chains in new perf data only ]

hot chain 1:
cycles: 36, hits: 3.36%
--------------------------
__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
main div.c:40
main div.c:39

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
---
tools/perf/Documentation/perf-diff.txt | 14 ++
tools/perf/builtin-diff.c | 170 +++++++++++++++++++++++--
2 files changed, 171 insertions(+), 13 deletions(-)

diff --git a/tools/perf/Documentation/perf-diff.txt b/tools/perf/Documentation/perf-diff.txt
index f50ca0fef0a4..296fea98ac07 100644
--- a/tools/perf/Documentation/perf-diff.txt
+++ b/tools/perf/Documentation/perf-diff.txt
@@ -182,6 +182,20 @@ OPTIONS
--tid=::
Only diff samples for given thread ID (comma separated list).

+--stream::
+ Enable hot streams comparison. Stream is a callchain which is
+ aggregated by the branch records from samples. The option can be
+ used with --before and --after if source line comparison is
+ required.
+
+--before::
+ Source code directory corresponding to perf.data.old. Should be
+ used with --stream and --after.
+
+--after::
+ Source code directory corresponding to perf.data. Should be
+ used with --stream and --before.
+
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 5e697cd2224a..9c801b9bc5bb 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -25,6 +25,8 @@
#include "util/map.h"
#include "util/spark.h"
#include "util/block-info.h"
+#include "util/srclist.h"
+#include "util/callchain.h"
#include <linux/err.h>
#include <linux/zalloc.h>
#include <subcmd/pager.h>
@@ -38,10 +40,15 @@
struct perf_diff {
struct perf_tool tool;
const char *time_str;
+ const char *before_dir;
+ const char *after_dir;
struct perf_time_interval *ptime_range;
int range_size;
int range_num;
bool has_br_stack;
+ bool src_cmp;
+ bool stream;
+ struct srclist *src_list;
};

/* Diff command specific HPP columns. */
@@ -72,6 +79,8 @@ struct data__file {
struct perf_data data;
int idx;
struct hists *hists;
+ struct callchain_streams *evsel_streams;
+ int nr_evsel_streams;
struct diff_hpp_fmt fmt[PERF_HPP_DIFF__MAX_INDEX];
};

@@ -106,6 +115,7 @@ 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] = {
@@ -393,6 +403,11 @@ 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,
@@ -411,14 +426,8 @@ 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, "
@@ -428,6 +437,23 @@ static int diff__process_sample_event(struct perf_tool *tool,

hist__account_cycles(sample->branch_stack, &al, sample, false,
NULL);
+ 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;
+ }
}

/*
@@ -995,6 +1021,53 @@ 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,
+ const char *base_dir __maybe_unused,
+ const char *pair_dir __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 callchain_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 = callchain_evsel_streams_get(data_base->evsel_streams,
+ data_base->nr_evsel_streams,
+ evsel_base->idx);
+ if (!es_base)
+ return -1;
+
+ es_pair = callchain_evsel_streams_get(data_pair->evsel_streams,
+ data_pair->nr_evsel_streams,
+ evsel_pair->idx);
+ if (!es_pair)
+ return -1;
+
+ callchain_match_streams(es_base, es_pair, pdiff.src_list);
+ callchain_stream_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",
+ pdiff.before_dir, pdiff.after_dir);
+}
+
static void data__free(struct data__file *d)
{
int col;
@@ -1108,6 +1181,19 @@ static int check_file_brstack(void)
return 0;
}

+static struct callchain_streams *create_evsel_streams(struct evlist *evlist,
+ int nr_streams_max,
+ int *nr_evsel_streams)
+{
+ struct callchain_streams *evsel_streams;
+
+ evsel_streams = callchain_evsel_streams_create(evlist,
+ nr_streams_max,
+ nr_evsel_streams);
+
+ return evsel_streams;
+}
+
static int __cmd_diff(void)
{
struct data__file *d;
@@ -1121,6 +1207,14 @@ static int __cmd_diff(void)
abstime_tmp = abstime_ostr;
ret = -EINVAL;

+ if (pdiff.src_cmp) {
+ pdiff.src_list = srclist__new(pdiff.before_dir,
+ pdiff.after_dir);
+
+ if (!pdiff.src_list)
+ goto out_free;
+ }
+
data__for_each_file(i, d) {
d->session = perf_session__new(&d->data, false, &pdiff.tool);
if (IS_ERR(d->session)) {
@@ -1152,9 +1246,21 @@ 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) {
@@ -1162,6 +1268,7 @@ static int __cmd_diff(void)
data__free(d);
}

+ out_free:
free(data__files);

if (pdiff.ptime_range)
@@ -1170,6 +1277,9 @@ static int __cmd_diff(void)
if (abstime_ostr)
free(abstime_ostr);

+ if (pdiff.src_list)
+ srclist__delete(pdiff.src_list);
+
return ret;
}

@@ -1227,6 +1337,15 @@ 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. "
+ "Can be used with --before and --after"),
+ OPT_STRING(0, "before", &pdiff.before_dir, "dir",
+ "Source code directory corresponding to perf.data.old. "
+ "WARNING: use with --after and --stream"),
+ OPT_STRING(0, "after", &pdiff.after_dir, "dir",
+ "Source code directory corresponding to perf.data. "
+ "WARNING: use with --before and --stream"),
OPT_END()
};

@@ -1886,6 +2005,19 @@ int cmd_diff(int argc, const char **argv)
if (cycles_hist && (compute != COMPUTE_CYCLES))
usage_with_options(diff_usage, options);

+ if (pdiff.stream) {
+ compute = COMPUTE_STREAM;
+ if ((pdiff.before_dir && !pdiff.after_dir) ||
+ (!pdiff.before_dir && pdiff.after_dir)) {
+ usage_with_options(diff_usage, options);
+ }
+
+ if (pdiff.before_dir && pdiff.after_dir)
+ pdiff.src_cmp = true;
+ } else if (pdiff.before_dir || pdiff.after_dir) {
+ usage_with_options(diff_usage, options);
+ }
+
symbol__annotation_init();

if (symbol__init(NULL) < 0)
@@ -1897,13 +2029,25 @@ 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;
+ 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