[PATCH 5/6] perf, tools, stat: Implement --metric-only mode

From: Andi Kleen
Date: Fri Feb 26 2016 - 19:28:38 EST


From: Andi Kleen <ak@xxxxxxxxxxxxxxx>

Add a new mode to only print metrics. Sometimes we don't care about
the raw values, just want the computed metrics. This allows more
compact printing, so with -I each sample is only a single line.
This also allows easier plotting and processing with other tools.

The main target is with using --topdown, but it also works with
-T and standard perf stat. A few metrics are not supported.

To avoiding having to hardcode all the metrics in the code it uses
a two pass approach: first compute dummy metrics and only
print the headers in the print_metric callback. Then use the callback
to print the actual values.

There are some additional changes
in the stat printout code to handle all metrics being on a single line.

One issue is that the column code doesn't know in advance what events
are not supported by the CPU, and it would be hard to find out
as this could change based on dynamic conditions. That causes
empty columns in some cases.

The output can be fairly wide, often you may need more than 80 columns.

Example:

% perf stat -a -I 1000 --metric-only
1.001452803 frontend cycles idle insn per cycle stalled cycles per insn branch-misses of all branches
1.001452803 158.91% 0.66 2.39 2.92%
2.002192321 180.63% 0.76 2.08 2.96%
3.003088282 150.59% 0.62 2.57 2.84%
4.004369835 196.20% 0.98 1.62 3.79%
5.005227314 231.98% 0.84 1.90 4.71%

v2: Lots of updates.
v3: Use slightly narrower columns
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
tools/perf/Documentation/perf-stat.txt | 4 +
tools/perf/builtin-stat.c | 207 +++++++++++++++++++++++++++++++--
2 files changed, 201 insertions(+), 10 deletions(-)

diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
index 3ae7907..3929ab0 100644
--- a/tools/perf/Documentation/perf-stat.txt
+++ b/tools/perf/Documentation/perf-stat.txt
@@ -139,6 +139,10 @@ Print count deltas every N milliseconds (minimum: 10ms)
The overhead percentage could be high in some cases, for instance with small, sub 100ms intervals. Use with caution.
example: 'perf stat -I 1000 -e cycles -a sleep 5'

+--metric-only::
+Only print computed metrics. Print them in a single line.
+Don't show any raw values. Not supported with -A or --per-thread.
+
--per-socket::
Aggregate counts per processor socket for system-wide mode measurements. This
is a useful mode to detect imbalance between sockets. To enable this mode,
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index c79e571..30bb0ac 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -122,6 +122,7 @@ static bool sync_run = false;
static unsigned int initial_delay = 0;
static unsigned int unit_width = 4; /* strlen("unit") */
static bool forever = false;
+static bool metric_only = false;
static struct timespec ref_time;
static struct cpu_map *aggr_map;
static aggr_get_id_t aggr_get_id;
@@ -827,6 +828,99 @@ static void print_metric_csv(void *ctx,
fprintf(out, "%s%s%s%s", csv_sep, vals, csv_sep, unit);
}

+#define METRIC_ONLY_LEN 20
+
+/* Filter out some columns that don't work well in metrics only mode */
+
+static bool valid_only_metric(const char *unit)
+{
+ if (!unit)
+ return false;
+ if (strstr(unit, "/sec") ||
+ strstr(unit, "hz") ||
+ strstr(unit, "Hz") ||
+ strstr(unit, "CPUs utilized"))
+ return false;
+ return true;
+}
+
+static const char *fixunit(char *buf, struct perf_evsel *evsel,
+ const char *unit)
+{
+ if (!strncmp(unit, "of all", 6)) {
+ snprintf(buf, 1024, "%s %s", perf_evsel__name(evsel),
+ unit);
+ return buf;
+ }
+ return unit;
+}
+
+static void print_metric_only(void *ctx, const char *color, const char *fmt,
+ const char *unit, double val)
+{
+ struct outstate *os = ctx;
+ FILE *out = os->fh;
+ int n;
+ char buf[1024];
+ unsigned mlen = METRIC_ONLY_LEN;
+
+ if (!valid_only_metric(unit))
+ return;
+ unit = fixunit(buf, os->evsel, unit);
+ if (color)
+ n = color_fprintf(out, color, fmt, val);
+ else
+ n = fprintf(out, fmt, val);
+ if (n > METRIC_ONLY_LEN)
+ n = METRIC_ONLY_LEN;
+ if (mlen < strlen(unit))
+ mlen = strlen(unit) + 1;
+ fprintf(out, "%*s", mlen - n, "");
+}
+
+static void print_metric_only_csv(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);
+ vals = buf;
+ while (isspace(*vals))
+ vals++;
+ ends = vals;
+ while (isdigit(*ends) || *ends == '.')
+ ends++;
+ *ends = 0;
+ fprintf(out, "%s%s", vals, csv_sep);
+}
+
+static void new_line_metric(void *ctx __maybe_unused)
+{
+}
+
+static void print_metric_header(void *ctx, const char *color __maybe_unused,
+ const char *fmt __maybe_unused,
+ const char *unit, double val __maybe_unused)
+{
+ struct outstate *os = ctx;
+ char tbuf[1024];
+
+ if (!valid_only_metric(unit))
+ return;
+ unit = fixunit(tbuf, os->evsel, unit);
+ if (csv_output)
+ fprintf(os->fh, "%s%s", unit, csv_sep);
+ else
+ fprintf(os->fh, "%-*s ", METRIC_ONLY_LEN, unit);
+}
+
static void nsec_printout(int id, int nr, struct perf_evsel *evsel, double avg)
{
FILE *output = stat_config.output;
@@ -918,9 +1012,16 @@ static void printout(int id, int nr, struct perf_evsel *counter, double uval,
print_metric_t pm = print_metric_std;
void (*nl)(void *);

- nl = new_line_std;
+ if (metric_only) {
+ nl = new_line_metric;
+ if (csv_output)
+ pm = print_metric_only_csv;
+ else
+ pm = print_metric_only;
+ } else
+ nl = new_line_std;

- if (csv_output) {
+ if (csv_output && !metric_only) {
static int aggr_fields[] = {
[AGGR_GLOBAL] = 0,
[AGGR_THREAD] = 1,
@@ -937,6 +1038,10 @@ static void printout(int id, int nr, struct perf_evsel *counter, double uval,
os.nfields++;
}
if (run == 0 || ena == 0 || counter->counts->scaled == -1) {
+ if (metric_only) {
+ pm(&os, NULL, "", "", 0);
+ return;
+ }
aggr_printout(counter, id, nr);

fprintf(stat_config.output, "%*s%s",
@@ -965,7 +1070,9 @@ static void printout(int id, int nr, struct perf_evsel *counter, double uval,
return;
}

- if (nsec_counter(counter))
+ if (metric_only)
+ /* nothing */;
+ else if (nsec_counter(counter))
nsec_printout(id, nr, counter, uval);
else
abs_printout(id, nr, counter, uval);
@@ -974,7 +1081,7 @@ static void printout(int id, int nr, struct perf_evsel *counter, double uval,
out.new_line = nl;
out.ctx = &os;

- if (csv_output) {
+ if (csv_output && !metric_only) {
print_noise(counter, noise);
print_running(run, ena);
}
@@ -982,7 +1089,7 @@ static void printout(int id, int nr, struct perf_evsel *counter, double uval,
perf_stat__print_shadow_stats(counter, uval,
first_shadow_cpu(counter, id),
&out);
- if (!csv_output) {
+ if (!csv_output && !metric_only) {
print_noise(counter, noise);
print_running(run, ena);
}
@@ -1018,6 +1125,7 @@ static void print_aggr(char *prefix)
int cpu, s, s2, id, nr;
double uval;
u64 ena, run, val;
+ bool first;

if (!(aggr_map || aggr_get_id))
return;
@@ -1025,7 +1133,11 @@ static void print_aggr(char *prefix)
aggr_update_shadow();

for (s = 0; s < aggr_map->nr; s++) {
+ if (prefix && metric_only)
+ fprintf(output, "%s", prefix);
+
id = aggr_map->map[s];
+ first = true;
evlist__for_each(evsel_list, counter) {
val = ena = run = 0;
nr = 0;
@@ -1038,13 +1150,20 @@ static void print_aggr(char *prefix)
run += perf_counts(counter->counts, cpu, 0)->run;
nr++;
}
- if (prefix)
+ if (first && metric_only) {
+ first = false;
+ aggr_printout(counter, id, nr);
+ }
+ if (prefix && !metric_only)
fprintf(output, "%s", prefix);

uval = val * counter->scale;
printout(id, nr, counter, uval, prefix, run, ena, 1.0);
- fputc('\n', output);
+ if (!metric_only)
+ fputc('\n', output);
}
+ if (metric_only)
+ fputc('\n', output);
}
}

@@ -1089,12 +1208,13 @@ static void print_counter_aggr(struct perf_evsel *counter, char *prefix)
avg_enabled = avg_stats(&ps->res_stats[1]);
avg_running = avg_stats(&ps->res_stats[2]);

- if (prefix)
+ if (prefix && !metric_only)
fprintf(output, "%s", prefix);

uval = avg * counter->scale;
printout(-1, 0, counter, uval, prefix, avg_running, avg_enabled, avg);
- fprintf(output, "\n");
+ if (!metric_only)
+ fprintf(output, "\n");
}

/*
@@ -1123,6 +1243,43 @@ static void print_counter(struct perf_evsel *counter, char *prefix)
}
}

+static int aggr_header_lens[] = {
+ [AGGR_CORE] = 18,
+ [AGGR_SOCKET] = 12,
+ [AGGR_NONE] = 15,
+ [AGGR_THREAD] = 24,
+ [AGGR_GLOBAL] = 0,
+};
+
+static void print_metric_headers(char *prefix)
+{
+ struct perf_stat_output_ctx out;
+ struct perf_evsel *counter;
+ struct outstate os = {
+ .fh = stat_config.output
+ };
+
+ if (prefix)
+ fprintf(stat_config.output, "%s", prefix);
+
+ if (!csv_output)
+ fprintf(stat_config.output, "%*s",
+ aggr_header_lens[stat_config.aggr_mode], "");
+
+ /* Print metrics headers only */
+ evlist__for_each(evsel_list, counter) {
+ os.evsel = counter;
+ out.ctx = &os;
+ out.print_metric = print_metric_header;
+ out.new_line = new_line_metric;
+ os.evsel = counter;
+ perf_stat__print_shadow_stats(counter, 0,
+ 0,
+ &out);
+ }
+ fputc('\n', stat_config.output);
+}
+
static void print_interval(char *prefix, struct timespec *ts)
{
FILE *output = stat_config.output;
@@ -1130,7 +1287,7 @@ static void print_interval(char *prefix, struct timespec *ts)

sprintf(prefix, "%6lu.%09lu%s", ts->tv_sec, ts->tv_nsec, csv_sep);

- if (num_print_interval == 0 && !csv_output) {
+ if (num_print_interval == 0 && !csv_output && !metric_only) {
switch (stat_config.aggr_mode) {
case AGGR_SOCKET:
fprintf(output, "# time socket cpus counts %*s events\n", unit_width, "unit");
@@ -1217,6 +1374,17 @@ static void print_counters(struct timespec *ts, int argc, const char **argv)
else
print_header(argc, argv);

+ if (metric_only) {
+ static int num_print_iv;
+
+ if (num_print_iv == 0)
+ print_metric_headers(prefix);
+ if (num_print_iv++ == 25)
+ num_print_iv = 0;
+ if (stat_config.aggr_mode == AGGR_GLOBAL && prefix)
+ fprintf(stat_config.output, "%s", prefix);
+ }
+
switch (stat_config.aggr_mode) {
case AGGR_CORE:
case AGGR_SOCKET:
@@ -1229,6 +1397,8 @@ static void print_counters(struct timespec *ts, int argc, const char **argv)
case AGGR_GLOBAL:
evlist__for_each(evsel_list, counter)
print_counter_aggr(counter, prefix);
+ if (metric_only)
+ fputc('\n', stat_config.output);
break;
case AGGR_NONE:
evlist__for_each(evsel_list, counter)
@@ -1353,6 +1523,8 @@ static const struct option stat_options[] = {
"aggregate counts per thread", AGGR_THREAD),
OPT_UINTEGER('D', "delay", &initial_delay,
"ms to wait before starting measurement after program start"),
+ OPT_BOOLEAN(0, "metric-only", &metric_only,
+ "Only print computed metrics. No raw values"),
OPT_END()
};

@@ -1993,6 +2165,21 @@ int cmd_stat(int argc, const char **argv, const char *prefix __maybe_unused)
goto out;
}

+ if (metric_only && stat_config.aggr_mode == AGGR_THREAD) {
+ fprintf(stderr, "--metric-only is not supported with --per-thread\n");
+ goto out;
+ }
+
+ if (metric_only && stat_config.aggr_mode == AGGR_NONE) {
+ fprintf(stderr, "--metric-only is not supported with -A\n");
+ goto out;
+ }
+
+ if (metric_only && run_count > 1) {
+ fprintf(stderr, "--metric-only is not supported with -r\n");
+ goto out;
+ }
+
if (output_fd < 0) {
fprintf(stderr, "argument to --log-fd must be a > 0\n");
parse_options_usage(stat_usage, stat_options, "log-fd", 0);
--
2.5.0