[PATCH] perf stat: add rusage utime and stime events

From: Florian Fischer
Date: Tue Apr 05 2022 - 16:22:54 EST


It bothered me that during benchmarking using perf stat (to collect
for example CPU cache events) I could not simultaneously retrieve the
times spend in user or kernel mode in a machine readable format.

When running perf stat the output for humans contains the times
reported by rusage and wait4.

$ perf stat -e cache-misses:u -- true

Performance counter stats for 'true':

4,206 cache-misses:u

0.001113619 seconds time elapsed

0.001175000 seconds user
0.000000000 seconds sys

But using perf stats' machine-readable format does not provide this
information.

$ perf stat -x, -e cache-misses:u -- true
4282,,cache-misses:u,492859,100.00,,

I found no way to retrieve this information using the available events
while using machine-readable output.

To solve this I added two new tool internal events 'rusage_user_time'
and 'rusage_system_time' as well as their aliases 'ru_utime' and
'ru_stime', similarly to the already present 'duration_time' event.

Both events use the already collected rusage information obtained by wait4.

Examples presenting cache-misses and rusage information in both human and
machine-readable form:

$ ./perf stat -e duration_time,ru_utime,ru_stime,cache-misses -- grep -q -r duration_time .

Performance counter stats for 'grep -q -r duration_time .':

67,422,542 ns duration_time:u
50,517 us ru_utime:u
16,839 us ru_stime:u
30,937 cache-misses:u

0.067422542 seconds time elapsed

0.050517000 seconds user
0.016839000 seconds sys

$ ./perf stat -x, -e duration_time,ru_utime,ru_stime,cache-misses -- grep -q -r duration_time .
72134524,ns,duration_time:u,72134524,100.00,,
65225,us,ru_utime:u,65225,100.00,,
6865,us,ru_stime:u,6865,100.00,,
38705,,cache-misses:u,71189328,100.00,,

Signed-off-by: Florian Fischer <florian.fischer@muhq.space>
---
tools/perf/builtin-stat.c | 41 ++++++++++++++++++++++++-------
tools/perf/util/evsel.c | 19 +++++++++------
tools/perf/util/evsel.h | 4 ++++
tools/perf/util/parse-events.c | 44 +++++++++++++++++++++++++++++-----
tools/perf/util/parse-events.l | 2 ++
tools/perf/util/stat-shadow.c | 2 ++
tools/perf/util/stat.h | 19 +++++++++++++++
7 files changed, 109 insertions(+), 22 deletions(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index a96f106dc93a..c73afc8f6da5 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -216,6 +216,7 @@ static struct perf_stat_config stat_config = {
.run_count = 1,
.metric_only_len = METRIC_ONLY_LEN,
.walltime_nsecs_stats = &walltime_nsecs_stats,
+ .ru_stats = &ru_stats,
.big_num = true,
.ctl_fd = -1,
.ctl_fd_ack = -1,
@@ -341,15 +342,35 @@ static int evsel__write_stat_event(struct evsel *counter, int cpu_map_idx, u32 t
static int read_single_counter(struct evsel *counter, int cpu_map_idx,
int thread, struct timespec *rs)
{
- if (counter->tool_event == PERF_TOOL_DURATION_TIME) {
- u64 val = rs->tv_nsec + rs->tv_sec*1000000000ULL;
- struct perf_counts_values *count =
- perf_counts(counter->counts, cpu_map_idx, thread);
- count->ena = count->run = val;
- count->val = val;
- return 0;
+ switch(counter->tool_event) {
+ case PERF_TOOL_DURATION_TIME: {
+ u64 val = rs->tv_nsec + rs->tv_sec*1000000000ULL;
+ struct perf_counts_values *count =
+ perf_counts(counter->counts, cpu_map_idx, thread);
+ count->ena = count->run = val;
+ count->val = val;
+ return 0;
+ }
+ case PERF_TOOL_RU_UTIME:
+ case PERF_TOOL_RU_STIME: {
+ u64 val;
+ struct perf_counts_values *count =
+ perf_counts(counter->counts, cpu_map_idx, thread);
+ if (counter->tool_event == PERF_TOOL_RU_UTIME)
+ val = ru_stats.ru_utime_usec_stat.mean;
+ else
+ val = ru_stats.ru_stime_usec_stat.mean;
+ count->ena = count->run = val;
+ count->val = val;
+ return 0;
+ }
+ default:
+ case PERF_TOOL_NONE:
+ return evsel__read_counter(counter, cpu_map_idx, thread);
+ case PERF_TOOL_LAST:
+ /* this case should never be reached */
+ return 0;
}
- return evsel__read_counter(counter, cpu_map_idx, thread);
}

/*
@@ -1010,8 +1031,10 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
evlist__reset_prev_raw_counts(evsel_list);
runtime_stat_reset(&stat_config);
perf_stat__reset_shadow_per_stat(&rt_stat);
- } else
+ } else {
update_stats(&walltime_nsecs_stats, t1 - t0);
+ update_rusage_stats(&ru_stats, &stat_config.ru_data);
+ }

/*
* Closing a group leader splits the group, and as we only disable
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 2a1729e7aee4..26cf7e76698b 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -597,6 +597,17 @@ static int evsel__sw_name(struct evsel *evsel, char *bf, size_t size)
return r + evsel__add_modifiers(evsel, bf + r, size - r);
}

+const char *evsel__tool_names[PERF_TOOL_LAST] = {
+ "duration_time",
+ "rusage_user_time",
+ "rusage_system_time",
+};
+
+static int evsel__tool_name(enum perf_tool_event ev, char *bf, size_t size)
+{
+ return scnprintf(bf, size, "%s", evsel__tool_names[ev]);
+}
+
static int __evsel__bp_name(char *bf, size_t size, u64 addr, u64 type)
{
int r;
@@ -723,12 +734,6 @@ static int evsel__raw_name(struct evsel *evsel, char *bf, size_t size)
return ret + evsel__add_modifiers(evsel, bf + ret, size - ret);
}

-static int evsel__tool_name(char *bf, size_t size)
-{
- int ret = scnprintf(bf, size, "duration_time");
- return ret;
-}
-
const char *evsel__name(struct evsel *evsel)
{
char bf[128];
@@ -754,7 +759,7 @@ const char *evsel__name(struct evsel *evsel)

case PERF_TYPE_SOFTWARE:
if (evsel->tool_event)
- evsel__tool_name(bf, sizeof(bf));
+ evsel__tool_name(evsel->tool_event, bf, sizeof(bf));
else
evsel__sw_name(evsel, bf, sizeof(bf));
break;
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 041b42d33bf5..2adb97383952 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -30,6 +30,9 @@ typedef int (evsel__sb_cb_t)(union perf_event *event, void *data);
enum perf_tool_event {
PERF_TOOL_NONE = 0,
PERF_TOOL_DURATION_TIME = 1,
+ PERF_TOOL_RU_UTIME = 2,
+ PERF_TOOL_RU_STIME = 3,
+ PERF_TOOL_LAST
};

/** struct evsel - event selector
@@ -258,6 +261,7 @@ extern const char *evsel__hw_cache_op[PERF_COUNT_HW_CACHE_OP_MAX][EVSEL__MAX_ALI
extern const char *evsel__hw_cache_result[PERF_COUNT_HW_CACHE_RESULT_MAX][EVSEL__MAX_ALIASES];
extern const char *evsel__hw_names[PERF_COUNT_HW_MAX];
extern const char *evsel__sw_names[PERF_COUNT_SW_MAX];
+extern const char *evsel__tool_names[PERF_TOOL_LAST];
extern char *evsel__bpf_counter_events;
bool evsel__match_bpf_counter_events(const char *name);

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 24997925ae00..13db69b71187 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -154,6 +154,21 @@ struct event_symbol event_symbols_sw[PERF_COUNT_SW_MAX] = {
},
};

+struct event_symbol event_symbols_tool[PERF_TOOL_LAST] = {
+ [PERF_TOOL_DURATION_TIME] = {
+ .symbol = "duration_time",
+ .alias = "",
+ },
+ [PERF_TOOL_RU_UTIME] = {
+ .symbol = "rusage_user_time",
+ .alias = "ru_utime",
+ },
+ [PERF_TOOL_RU_STIME] = {
+ .symbol = "rusage_system_time",
+ .alias = "ru_stime",
+ },
+};
+
#define __PERF_EVENT_FIELD(config, name) \
((config & PERF_EVENT_##name##_MASK) >> PERF_EVENT_##name##_SHIFT)

@@ -406,6 +421,10 @@ static int add_event_tool(struct list_head *list, int *idx,
free((char *)evsel->unit);
evsel->unit = strdup("ns");
}
+ else if (tool_event == PERF_TOOL_RU_UTIME || tool_event == PERF_TOOL_RU_STIME) {
+ free((char *)evsel->unit);
+ evsel->unit = strdup("us");
+ }
return 0;
}

@@ -3055,21 +3074,34 @@ int print_hwcache_events(const char *event_glob, bool name_only)
return evt_num;
}

-static void print_tool_event(const char *name, const char *event_glob,
+static void print_tool_event(const struct event_symbol *syms, const char *event_glob,
bool name_only)
{
- if (event_glob && !strglobmatch(name, event_glob))
+ if (syms->symbol == NULL)
+ return;
+
+ if (event_glob && !(strglobmatch(syms->symbol, event_glob) ||
+ (syms->alias && strglobmatch(syms->alias, event_glob))))
return;
+
if (name_only)
- printf("%s ", name);
- else
+ printf("%s ", syms->symbol);
+ else {
+ char name[MAX_NAME_LEN];
+ if (syms->alias)
+ snprintf(name, MAX_NAME_LEN, "%s OR %s", syms->symbol, syms->alias);
+ else
+ strlcpy(name, syms->symbol, MAX_NAME_LEN);
printf(" %-50s [%s]\n", name, "Tool event");
-
+ }
}

void print_tool_events(const char *event_glob, bool name_only)
{
- print_tool_event("duration_time", event_glob, name_only);
+ // Start at 1 because the first enum entry symbols no tool event
+ for (int i = 0; i < PERF_TOOL_LAST; ++i) {
+ print_tool_event(event_symbols_tool + i, event_glob, name_only);
+ }
if (pager_in_use())
printf("\n");
}
diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
index 5b6e4b5249cf..3c7227b8035c 100644
--- a/tools/perf/util/parse-events.l
+++ b/tools/perf/util/parse-events.l
@@ -353,6 +353,8 @@ alignment-faults { return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_AL
emulation-faults { return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_EMULATION_FAULTS); }
dummy { return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_DUMMY); }
duration_time { return tool(yyscanner, PERF_TOOL_DURATION_TIME); }
+rusage_user_time|ru_utime { return tool(yyscanner, PERF_TOOL_RU_UTIME); }
+rusage_system_time|ru_stime { return tool(yyscanner, PERF_TOOL_RU_STIME); }
bpf-output { return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_BPF_OUTPUT); }
cgroup-switches { return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_CGROUP_SWITCHES); }

diff --git a/tools/perf/util/stat-shadow.c b/tools/perf/util/stat-shadow.c
index 10af7804e482..ea4c35e4f1da 100644
--- a/tools/perf/util/stat-shadow.c
+++ b/tools/perf/util/stat-shadow.c
@@ -26,6 +26,7 @@

struct runtime_stat rt_stat;
struct stats walltime_nsecs_stats;
+struct rusage_stats ru_stats;

struct saved_value {
struct rb_node rb_node;
@@ -199,6 +200,7 @@ void perf_stat__reset_shadow_stats(void)
{
reset_stat(&rt_stat);
memset(&walltime_nsecs_stats, 0, sizeof(walltime_nsecs_stats));
+ memset(&ru_stats, 0, sizeof(ru_stats));
}

void perf_stat__reset_shadow_per_stat(struct runtime_stat *st)
diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
index 335d19cc3063..b14a45d8af63 100644
--- a/tools/perf/util/stat.h
+++ b/tools/perf/util/stat.h
@@ -108,6 +108,11 @@ struct runtime_stat {
struct rblist value_list;
};

+struct rusage_stats {
+ struct stats ru_utime_usec_stat;
+ struct stats ru_stime_usec_stat;
+};
+
typedef struct aggr_cpu_id (*aggr_get_id_t)(struct perf_stat_config *config, struct perf_cpu cpu);

struct perf_stat_config {
@@ -148,6 +153,7 @@ struct perf_stat_config {
const char *csv_sep;
struct stats *walltime_nsecs_stats;
struct rusage ru_data;
+ struct rusage_stats *ru_stats;
struct cpu_aggr_map *aggr_map;
aggr_get_id_t aggr_get_id;
struct cpu_aggr_map *cpus_aggr_map;
@@ -177,6 +183,18 @@ static inline void init_stats(struct stats *stats)
stats->max = 0;
}

+static inline void init_rusage_stats(struct rusage_stats *ru_stats) {
+ init_stats(&ru_stats->ru_utime_usec_stat);
+ init_stats(&ru_stats->ru_stime_usec_stat);
+}
+
+static inline void update_rusage_stats(struct rusage_stats *ru_stats, struct rusage* rusage) {
+ update_stats(&ru_stats->ru_utime_usec_stat,
+ (rusage->ru_utime.tv_usec + rusage->ru_utime.tv_sec * 1000000ULL));
+ update_stats(&ru_stats->ru_stime_usec_stat,
+ (rusage->ru_stime.tv_usec + rusage->ru_stime.tv_sec * 1000000ULL));
+}
+
struct evsel;
struct evlist;

@@ -196,6 +214,7 @@ bool __perf_stat_evsel__is(struct evsel *evsel, enum perf_stat_evsel_id id);

extern struct runtime_stat rt_stat;
extern struct stats walltime_nsecs_stats;
+extern struct rusage_stats ru_stats;

typedef void (*print_metric_t)(struct perf_stat_config *config,
void *ctx, const char *color, const char *unit,
--
2.35.1