[PATCH v6 1/2] perf stat: Add JSON output option

Ian Rogers
2022-07-07T20:12:35Z

From: Claire Jensen <cjense@google.com>

CSV output is tricky to format and column layout changes are susceptible
to breaking parsers. New JSON-formatted output has variable names to
identify fields that are consistent and informative, making
the output parseable.

CSV output example:

1.20,msec,task-clock:u,1204272,100.00,0.697,CPUs utilized
0,,context-switches:u,1204272,100.00,0.000,/sec
0,,cpu-migrations:u,1204272,100.00,0.000,/sec
70,,page-faults:u,1204272,100.00,58.126,K/sec

JSON output example:

{"counter-value" : "3805.723968", "unit" : "msec", "event" :
"cpu-clock", "event-runtime" : 3805731510100.00, "pcnt-running"
: 100.00, "metric-value" : 4.007571, "metric-unit" : "CPUs utilized"}
{"counter-value" : "6166.000000", "unit" : "", "event" :
"context-switches", "event-runtime" : 3805723045100.00, "pcnt-running"
: 100.00, "metric-value" : 1.620191, "metric-unit" : "K/sec"}
{"counter-value" : "466.000000", "unit" : "", "event" :
"cpu-migrations", "event-runtime" : 3805727613100.00, "pcnt-running"
: 100.00, "metric-value" : 122.447136, "metric-unit" : "/sec"}
{"counter-value" : "208.000000", "unit" : "", "event" :
"page-faults", "event-runtime" : 3805726799100.00, "pcnt-running"
: 100.00, "metric-value" : 54.654516, "metric-unit" : "/sec"}

Also added documentation for JSON option.
There is some tidy up of CSV code including a potential memory over run
in the os.nfields set up. To facilitate this an AGGR_MAX value is added.

Signed-off-by: Claire Jensen <cjense@google.com>
Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/Documentation/perf-stat.txt | 21 ++
tools/perf/builtin-stat.c | 6 +
tools/perf/util/stat-display.c | 384 ++++++++++++++++++-------
tools/perf/util/stat.c | 1 +
tools/perf/util/stat.h | 2 +
5 files changed, 308 insertions(+), 106 deletions(-)

diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
index d8a33f4a47c5..d7ff1867feda 100644
--- a/tools/perf/Documentation/perf-stat.txt
+++ b/tools/perf/Documentation/perf-stat.txt
@@ -570,6 +570,27 @@ Additional metrics may be printed with all earlier fields being empty.

include::intel-hybrid.txt[]

+JSON FORMAT
+-----------
+
+With -j, perf stat is able to print out a JSON format output
+that can be used for parsing.
+
+- timestamp : optional usec time stamp in fractions of second (with -I)
+- optional aggregate options:
+ - core : core identifier (with --per-core)
+ - die : die identifier (with --per-die)
+ - socket : socket identifier (with --per-socket)
+ - node : node identifier (with --per-node)
+ - thread : thread identifier (with --per-thread)
+- counter-value : counter value
+- unit : unit of the counter value or empty
+- event : event name
+- variance : optional variance if multiple values are collected (with -r)
+- runtime : run time of counter
+- metric-value : optional metric value
+- metric-unit : optional unit of metric
+
SEE ALSO
--------
linkperf:perf-top[1], linkperf:perf-list[1]
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 4ce87a8eb7d7..6c7e59440e3a 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -1256,6 +1256,8 @@ static struct option stat_options[] = {
"Merge identical named hybrid events"),
OPT_STRING('x', "field-separator", &stat_config.csv_sep, "separator",
"print counts with custom separator"),
+ OPT_BOOLEAN('j', "json-output", &stat_config.json_output,
+ "print counts in JSON format"),
OPT_CALLBACK('G', "cgroup", &evsel_list, "name",
"monitor event in cgroup name only", parse_stat_cgroups),
OPT_STRING(0, "for-each-cgroup", &stat_config.cgroup_list, "name",
@@ -1442,6 +1444,7 @@ static aggr_cpu_id_get_t aggr_mode__get_aggr(enum aggr_mode aggr_mode)
case AGGR_GLOBAL:
case AGGR_THREAD:
case AGGR_UNSET:
+ case AGGR_MAX:
default:
return NULL;
}
@@ -1466,6 +1469,7 @@ static aggr_get_id_t aggr_mode__get_id(enum aggr_mode aggr_mode)
case AGGR_GLOBAL:
case AGGR_THREAD:
case AGGR_UNSET:
+ case AGGR_MAX:
default:
return NULL;
}
@@ -1616,6 +1620,7 @@ static aggr_cpu_id_get_t aggr_mode__get_aggr_file(enum aggr_mode aggr_mode)
case AGGR_GLOBAL:
case AGGR_THREAD:
case AGGR_UNSET:
+ case AGGR_MAX:
default:
return NULL;
}
@@ -1636,6 +1641,7 @@ static aggr_get_id_t aggr_mode__get_id_file(enum aggr_mode aggr_mode)
case AGGR_GLOBAL:
case AGGR_THREAD:
case AGGR_UNSET:
+ case AGGR_MAX:
default:
return NULL;
}
diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
index 606f09b09226..2bbd11446fa9 100644
--- a/tools/perf/util/stat-display.c
+++ b/tools/perf/util/stat-display.c
@@ -28,15 +28,21 @@
static void print_running(struct perf_stat_config *config,
u64 run, u64 ena)
{
- if (config->csv_output) {
- fprintf(config->output, "%s%" PRIu64 "%s%.2f",
- config->csv_sep,
- run,
- config->csv_sep,
- ena ? 100.0 * run / ena : 100.0);
- } else if (run != ena) {
+
+ double enabled_percent = 100;
+
+ if (run != ena)
+ enabled_percent = 100 * run / ena;
+ if (config->json_output)
+ fprintf(config->output,
+ "\"event-runtime\" : %lu, \"pcnt-running\" : %.2f, ",
+ run, enabled_percent);
+ else if (config->csv_output)
+ fprintf(config->output,
+ "%s%" PRIu64 "%s%.2f", config->csv_sep,
+ run, config->csv_sep, enabled_percent);
+ else if (run != ena)
fprintf(config->output, " (%.2f%%)", 100.0 * run / ena);
- }
}

static void print_noise_pct(struct perf_stat_config *config,
@@ -44,7 +50,9 @@ static void print_noise_pct(struct perf_stat_config *config,
{
double pct = rel_stddev_stats(total, avg);

- if (config->csv_output)
+ if (config->json_output)
+ fprintf(config->output, "\"variance\" : %.2f, ", pct);
+ else if (config->csv_output)
fprintf(config->output, "%s%.2f%%", config->csv_sep, pct);
else if (pct)
fprintf(config->output, " ( +-%6.2f%% )", pct);
@@ -66,7 +74,11 @@ static void print_cgroup(struct perf_stat_config *config, struct evsel *evsel)
{
if (nr_cgroups) {
const char *cgrp_name = evsel->cgrp ? evsel->cgrp->name : "";
- fprintf(config->output, "%s%s", config->csv_sep, cgrp_name);
+
+ if (config->json_output)
+ fprintf(config->output, "\"cgroup\" : \"%s\", ", cgrp_name);
+ else
+ fprintf(config->output, "%s%s", config->csv_sep, cgrp_name);
}
}

@@ -74,69 +86,123 @@ static void print_cgroup(struct perf_stat_config *config, struct evsel *evsel)
static void aggr_printout(struct perf_stat_config *config,
struct evsel *evsel, struct aggr_cpu_id id, int nr)
{
+
+
+ if (config->json_output && !config->interval)
+ fprintf(config->output, "{");
+
switch (config->aggr_mode) {
case AGGR_CORE:
- fprintf(config->output, "S%d-D%d-C%*d%s%*d%s",
- id.socket,
- id.die,
- config->csv_output ? 0 : -8,
- id.core,
- config->csv_sep,
- config->csv_output ? 0 : 4,
- nr,
- config->csv_sep);
+ if (config->json_output) {
+ fprintf(config->output,
+ "\"core\" : \"S%d-D%d-C%d\", \"aggregate-number\" : %d, ",
+ id.socket,
+ id.die,
+ id.core,
+ nr);
+ } else {
+ fprintf(config->output, "S%d-D%d-C%*d%s%*d%s",
+ id.socket,
+ id.die,
+ config->csv_output ? 0 : -8,
+ id.core,
+ config->csv_sep,
+ config->csv_output ? 0 : 4,
+ nr,
+ config->csv_sep);
+ }
break;
case AGGR_DIE:
- fprintf(config->output, "S%d-D%*d%s%*d%s",
- id.socket,
- config->csv_output ? 0 : -8,
- id.die,
- config->csv_sep,
- config->csv_output ? 0 : 4,
- nr,
- config->csv_sep);
+ if (config->json_output) {
+ fprintf(config->output,
+ "\"die\" : \"S%d-D%d\", \"aggregate-number\" : %d, ",
+ id.socket,
+ id.die,
+ nr);
+ } else {
+ fprintf(config->output, "S%d-D%*d%s%*d%s",
+ id.socket,
+ config->csv_output ? 0 : -8,
+ id.die,
+ config->csv_sep,
+ config->csv_output ? 0 : 4,
+ nr,
+ config->csv_sep);
+ }
break;
case AGGR_SOCKET:
- fprintf(config->output, "S%*d%s%*d%s",
- config->csv_output ? 0 : -5,
- id.socket,
- config->csv_sep,
- config->csv_output ? 0 : 4,
- nr,
- config->csv_sep);
- break;
+ if (config->json_output) {
+ fprintf(config->output,
+ "\"socket\" : \"S%d\", \"aggregate-number\" : %d, ",
+ id.socket,
+ nr);
+ } else {
+ fprintf(config->output, "S%*d%s%*d%s",
+ config->csv_output ? 0 : -5,
+ id.socket,
+ config->csv_sep,
+ config->csv_output ? 0 : 4,
+ nr,
+ config->csv_sep);
+ }
+ break;
case AGGR_NODE:
- fprintf(config->output, "N%*d%s%*d%s",
- config->csv_output ? 0 : -5,
- id.node,
- config->csv_sep,
- config->csv_output ? 0 : 4,
- nr,
- config->csv_sep);
- break;
+ if (config->json_output) {
+ fprintf(config->output, "\"node\" : \"N%d\", \"aggregate-number\" : %d, ",
+ id.node,
+ nr);
+ } else {
+ fprintf(config->output, "N%*d%s%*d%s",
+ config->csv_output ? 0 : -5,
+ id.node,
+ config->csv_sep,
+ config->csv_output ? 0 : 4,
+ nr,
+ config->csv_sep);
+ }
+ break;
case AGGR_NONE:
- if (evsel->percore && !config->percore_show_thread) {
- fprintf(config->output, "S%d-D%d-C%*d%s",
- id.socket,
- id.die,
- config->csv_output ? 0 : -3,
- id.core, config->csv_sep);
- } else if (id.cpu.cpu > -1) {
- fprintf(config->output, "CPU%*d%s",
- config->csv_output ? 0 : -7,
- id.cpu.cpu, config->csv_sep);
+ if (config->json_output) {
+ if (evsel->percore && !config->percore_show_thread) {
+ fprintf(config->output, "\"core\" : \"S%d-D%d-C%d\"",
+ id.socket,
+ id.die,
+ id.core);
+ } else if (id.core > -1) {
+ fprintf(config->output, "\"cpu\" : \"%d\", ",
+ id.cpu.cpu);
+ }
+ } else {
+ if (evsel->percore && !config->percore_show_thread) {
+ fprintf(config->output, "S%d-D%d-C%*d%s",
+ id.socket,
+ id.die,
+ config->csv_output ? 0 : -3,
+ id.core, config->csv_sep);
+ } else if (id.core > -1) {
+ fprintf(config->output, "CPU%*d%s",
+ config->csv_output ? 0 : -7,
+ id.cpu.cpu, config->csv_sep);
+ }
}
break;
case AGGR_THREAD:
- fprintf(config->output, "%*s-%*d%s",
- config->csv_output ? 0 : 16,
- perf_thread_map__comm(evsel->core.threads, id.thread),
- config->csv_output ? 0 : -8,
- perf_thread_map__pid(evsel->core.threads, id.thread),
- config->csv_sep);
+ if (config->json_output) {
+ fprintf(config->output, "\"thread\" : \"%s-%d\", ",
+ perf_thread_map__comm(evsel->core.threads, id.thread),
+ perf_thread_map__pid(evsel->core.threads, id.thread));
+ } else {
+ fprintf(config->output, "%*s-%*d%s",
+ config->csv_output ? 0 : 16,
+ perf_thread_map__comm(evsel->core.threads, id.thread),
+ config->csv_output ? 0 : -8,
+ perf_thread_map__pid(evsel->core.threads, id.thread),
+ config->csv_sep);
+ }
break;
case AGGR_GLOBAL:
case AGGR_UNSET:
+ case AGGR_MAX:
default:
break;
}
@@ -234,6 +300,31 @@ static void print_metric_csv(struct perf_stat_config *config __maybe_unused,
fprintf(out, "%s%s%s%s", config->csv_sep, vals, config->csv_sep, skip_spaces(unit));
}

+static void print_metric_json(struct perf_stat_config *config __maybe_unused,
+ void *ctx,
+ const char *color __maybe_unused,
+ const char *fmt __maybe_unused,
+ const char *unit, double val)
+{
+ struct outstate *os = ctx;
+ FILE *out = os->fh;
+
+ fprintf(out, "\"metric-value\" : %f, ", val);
+ fprintf(out, "\"metric-unit\" : \"%s\"", unit);
+ if (!config->metric_only)
+ fprintf(out, "}");
+}
+
+static void new_line_json(struct perf_stat_config *config, void *ctx)
+{
+ struct outstate *os = ctx;
+
+ fputc('\n', os->fh);
+ if (os->prefix)
+ fprintf(os->fh, "%s", os->prefix);
+ aggr_printout(config, os->evsel, os->id, os->nr);
+}
+
/* Filter out some columns that don't work well in metrics only mode */

static bool valid_only_metric(const char *unit)
@@ -300,6 +391,27 @@ static void print_metric_only_csv(struct perf_stat_config *config __maybe_unused
fprintf(out, "%s%s", vals, config->csv_sep);
}

+static void print_metric_only_json(struct perf_stat_config *config __maybe_unused,
+ void *ctx, const char *color __maybe_unused,
+ const char *fmt,
+ const char *unit, double val)
+{
+ struct outstate *os = ctx;
+ FILE *out = os->fh;
+ char buf[64], *vals, *ends;
+ char tbuf[1024];
+
+ if (!valid_only_metric(unit))
+ return;
+ unit = fixunit(tbuf, os->evsel, unit);
+ snprintf(buf, sizeof(buf), fmt, val);
+ ends = vals = skip_spaces(buf);
+ while (isdigit(*ends) || *ends == '.')
+ ends++;
+ *ends = 0;
+ fprintf(out, "{\"metric-value\" : \"%s\"}", vals);
+}
+
static void new_line_metric(struct perf_stat_config *config __maybe_unused,
void *ctx __maybe_unused)
{
@@ -318,10 +430,13 @@ static void print_metric_header(struct perf_stat_config *config,
os->evsel->priv != os->evsel->evlist->selected->priv)
return;

- if (!valid_only_metric(unit))
+ if (!valid_only_metric(unit) && !config->json_output)
return;
unit = fixunit(tbuf, os->evsel, unit);
- if (config->csv_output)
+
+ if (config->json_output)
+ fprintf(os->fh, "\"unit\" : \"%s\"", unit);
+ else if (config->csv_output)
fprintf(os->fh, "%s%s", unit, config->csv_sep);
else
fprintf(os->fh, "%*s ", config->metric_only_len, unit);
@@ -367,14 +482,28 @@ static void abs_printout(struct perf_stat_config *config,

aggr_printout(config, evsel, id, nr);

- fprintf(output, fmt, avg, config->csv_sep);
+ if (config->json_output)
+ fprintf(output, "\"counter-value\" : \"%f\", ", avg);
+ else
+ fprintf(output, fmt, avg, config->csv_sep);
+
+ if (config->json_output) {
+ if (evsel->unit) {
+ fprintf(output, "\"unit\" : \"%s\", ",
+ evsel->unit);
+ }
+ } else {
+ if (evsel->unit)
+ fprintf(output, "%-*s%s",
+ config->csv_output ? 0 : config->unit_width,
+ evsel->unit, config->csv_sep);
+ }

- if (evsel->unit)
- fprintf(output, "%-*s%s",
- config->csv_output ? 0 : config->unit_width,
- evsel->unit, config->csv_sep);

- fprintf(output, "%-*s", config->csv_output ? 0 : 25, evsel__name(evsel));
+ if (config->json_output)
+ fprintf(output, "\"event\" : \"%s\", ", evsel__name(evsel));
+ else
+ fprintf(output, "%-*s", config->csv_output ? 0 : 25, evsel__name(evsel));

print_cgroup(config, evsel);
}
@@ -416,34 +545,30 @@ static void printout(struct perf_stat_config *config, struct aggr_cpu_id id, int
.nr = nr,
.evsel = counter,
};
- print_metric_t pm = print_metric_std;
+ print_metric_t pm;
new_line_t nl;

- if (config->metric_only) {
- nl = new_line_metric;
- if (config->csv_output)
- pm = print_metric_only_csv;
- else
- pm = print_metric_only;
- } else
- nl = new_line_std;
-
- if (config->csv_output && !config->metric_only) {
- static int aggr_fields[] = {
- [AGGR_GLOBAL] = 0,
- [AGGR_THREAD] = 1,
+ if (config->csv_output) {
+ static const int aggr_fields[AGGR_MAX] = {
[AGGR_NONE] = 1,
+ [AGGR_GLOBAL] = 0,
[AGGR_SOCKET] = 2,
[AGGR_DIE] = 2,
[AGGR_CORE] = 2,
+ [AGGR_THREAD] = 1,
+ [AGGR_UNSET] = 0,
+ [AGGR_NODE] = 0,
};

- pm = print_metric_csv;
- nl = new_line_csv;
- os.nfields = 3;
- os.nfields += aggr_fields[config->aggr_mode];
- if (counter->cgrp)
- os.nfields++;
+ pm = config->metric_only ? print_metric_only_csv : print_metric_csv;
+ nl = config->metric_only ? new_line_metric : new_line_csv;
+ os.nfields = 3 + aggr_fields[config->aggr_mode] + (counter->cgrp ? 1 : 0);
+ } else if (config->json_output) {
+ pm = config->metric_only ? print_metric_only_json : print_metric_json;
+ nl = config->metric_only ? new_line_metric : new_line_json;
+ } else {
+ pm = config->metric_only ? print_metric_only : print_metric_std;
+ nl = config->metric_only ? new_line_metric : new_line_std;
}

if (!config->no_csv_summary && config->csv_output &&
@@ -458,10 +583,15 @@ static void printout(struct perf_stat_config *config, struct aggr_cpu_id id, int
}
aggr_printout(config, counter, id, nr);

- fprintf(config->output, "%*s%s",
- config->csv_output ? 0 : 18,
- counter->supported ? CNTR_NOT_COUNTED : CNTR_NOT_SUPPORTED,
- config->csv_sep);
+ if (config->json_output) {
+ fprintf(config->output, "\"counter-value\" : \"%s\", ",
+ counter->supported ? CNTR_NOT_COUNTED : CNTR_NOT_SUPPORTED);
+ } else {
+ fprintf(config->output, "%*s%s",
+ config->csv_output ? 0 : 18,
+ counter->supported ? CNTR_NOT_COUNTED : CNTR_NOT_SUPPORTED,
+ config->csv_sep);
+ }

if (counter->supported) {
if (!evlist__has_hybrid(counter->evlist)) {
@@ -471,21 +601,32 @@ static void printout(struct perf_stat_config *config, struct aggr_cpu_id id, int
}
}

- fprintf(config->output, "%-*s%s",
- config->csv_output ? 0 : config->unit_width,
- counter->unit, config->csv_sep);
+ if (config->json_output) {
+ fprintf(config->output, "\"unit\" : \"%s\", ", counter->unit);
+ } else {
+ fprintf(config->output, "%-*s%s",
+ config->csv_output ? 0 : config->unit_width,
+ counter->unit, config->csv_sep);
+ }

- fprintf(config->output, "%*s",
- config->csv_output ? 0 : -25, evsel__name(counter));
+ if (config->json_output) {
+ fprintf(config->output, "\"event\" : \"%s\", ",
+ evsel__name(counter));
+ } else {
+ fprintf(config->output, "%*s",
+ config->csv_output ? 0 : -25, evsel__name(counter));
+ }

print_cgroup(config, counter);

- if (!config->csv_output)
+ if (!config->csv_output && !config->json_output)
pm(config, &os, NULL, NULL, "", 0);
print_noise(config, counter, noise);
print_running(config, run, ena);
if (config->csv_output)
pm(config, &os, NULL, NULL, "", 0);
+ else if (config->json_output)
+ pm(config, &os, NULL, NULL, "", 0);
return;
}

@@ -500,12 +641,15 @@ static void printout(struct perf_stat_config *config, struct aggr_cpu_id id, int
if (config->csv_output && !config->metric_only) {
print_noise(config, counter, noise);
print_running(config, run, ena);
+ } else if (config->json_output && !config->metric_only) {
+ print_noise(config, counter, noise);
+ print_running(config, run, ena);
}

perf_stat__print_shadow_stats(config, counter, uval,
first_shadow_cpu_map_idx(config, counter, &id),
&out, &config->metric_events, st);
- if (!config->csv_output && !config->metric_only) {
+ if (!config->csv_output && !config->metric_only && !config->json_output) {
print_noise(config, counter, noise);
print_running(config, run, ena);
}
@@ -1004,8 +1148,12 @@ static void print_metric_headers(struct perf_stat_config *config,
struct outstate os = {
.fh = config->output
};
+ bool first = true;
+
+ if (config->json_output && !config->interval)
+ fprintf(config->output, "{");

- if (prefix)
+ if (prefix && !config->json_output)
fprintf(config->output, "%s", prefix);

if (!config->csv_output && !no_indent)
@@ -1025,6 +1173,9 @@ static void print_metric_headers(struct perf_stat_config *config,
os.evsel = counter;
out.ctx = &os;
out.print_metric = print_metric_header;
+ if (!first && config->json_output)
+ fprintf(config->output, ", ");
+ first = false;
out.new_line = new_line_metric;
out.force_header = true;
perf_stat__print_shadow_stats(config, counter, 0,
@@ -1033,6 +1184,8 @@ static void print_metric_headers(struct perf_stat_config *config,
&config->metric_events,
&rt_stat);
}
+ if (config->json_output)
+ fprintf(config->output, "}");
fputc('\n', config->output);
}

@@ -1048,10 +1201,18 @@ static void print_interval(struct perf_stat_config *config,
if (config->interval_clear)
puts(CONSOLE_CLEAR);

- if (!config->iostat_run)
- sprintf(prefix, "%6lu.%09lu%s", (unsigned long) ts->tv_sec, ts->tv_nsec, config->csv_sep);
-
- if ((num_print_interval == 0 && !config->csv_output) || config->interval_clear) {
+ if (!config->iostat_run && !config->json_output)
+ sprintf(prefix, "%6lu.%09lu%s", (unsigned long) ts->tv_sec,
+ ts->tv_nsec, config->csv_sep);
+ if (!config->iostat_run && config->json_output && !config->metric_only)
+ sprintf(prefix, "{\"interval\" : %lu.%09lu, ", (unsigned long)
+ ts->tv_sec, ts->tv_nsec);
+ if (!config->iostat_run && config->json_output && config->metric_only)
+ sprintf(prefix, "{\"interval\" : %lu.%09lu}", (unsigned long)
+ ts->tv_sec, ts->tv_nsec);
+
+ if ((num_print_interval == 0 && !config->csv_output && !config->json_output)
+ || config->interval_clear) {
switch (config->aggr_mode) {
case AGGR_NODE:
fprintf(output, "# time node cpus");
@@ -1091,12 +1252,19 @@ static void print_interval(struct perf_stat_config *config,
fprintf(output, " counts %*s events\n", unit_width, "unit");
}
case AGGR_UNSET:
+ case AGGR_MAX:
break;
}
}

- if ((num_print_interval == 0 || config->interval_clear) && metric_only)
+ if ((num_print_interval == 0 || config->interval_clear)
+ && metric_only && !config->json_output)
print_metric_headers(config, evlist, " ", true);
+ if ((num_print_interval == 0 || config->interval_clear)
+ && metric_only && config->json_output) {
+ fprintf(output, "{");
+ print_metric_headers(config, evlist, " ", true);
+ }
if (++num_print_interval == 25)
num_print_interval = 0;
}
@@ -1110,7 +1278,7 @@ static void print_header(struct perf_stat_config *config,

fflush(stdout);

- if (!config->csv_output) {
+ if (!config->csv_output && !config->json_output) {
fprintf(output, "\n");
fprintf(output, " Performance counter stats for ");
if (_target->bpf_str)
@@ -1303,6 +1471,9 @@ void evlist__print_counters(struct evlist *evlist, struct perf_stat_config *conf
num_print_iv = 0;
if (config->aggr_mode == AGGR_GLOBAL && prefix && !config->iostat_run)
fprintf(config->output, "%s", prefix);
+
+ if (config->json_output && !config->metric_only)
+ fprintf(config->output, "}");
}

switch (config->aggr_mode) {
@@ -1341,12 +1512,13 @@ void evlist__print_counters(struct evlist *evlist, struct perf_stat_config *conf
}
}
break;
+ case AGGR_MAX:
case AGGR_UNSET:
default:
break;
}

- if (!interval && !config->csv_output)
+ if (!interval && !config->csv_output && !config->json_output)
print_footer(config);

fflush(config->output);
diff --git a/tools/perf/util/stat.c b/tools/perf/util/stat.c
index 37ea2d044708..0882b4754fcf 100644
--- a/tools/perf/util/stat.c
+++ b/tools/perf/util/stat.c
@@ -401,6 +401,7 @@ process_counter_values(struct perf_stat_config *config, struct evsel *evsel,
aggr->ena += count->ena;
aggr->run += count->run;
case AGGR_UNSET:
+ case AGGR_MAX:
default:
break;
}
diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
index b5aeb8e6d34b..668250022f8c 100644
--- a/tools/perf/util/stat.h
+++ b/tools/perf/util/stat.h
@@ -57,6 +57,7 @@ enum aggr_mode {
AGGR_THREAD,
AGGR_UNSET,
AGGR_NODE,
+ AGGR_MAX
};

enum {
@@ -121,6 +122,7 @@ struct perf_stat_config {
bool no_inherit;
bool identifier;
bool csv_output;
+ bool json_output;
bool interval_clear;
bool metric_only;
bool null_run;
--
2.37.0.rc0.161.g10f37bed90-goog