[PATCH 3/3] perf stat: Add --metric option

[Jiri Olsa]

Adding --metric option that allows to specify metric on the command
line, like:

  # perf stat  --metric 'DECODED_ICACHE_UOPS% = 100 * (idq.dsb_uops / \
    (idq.ms_uops + idq.mite_uops + idq.dsb_uops + lsd.uops))' ...

The syntax of the --metric option argument is:

  [name[/unit]=]expression

where:
  name - is string that will identify expression in results
          (can't have = or /) default is "user metric"
  unit - is conversion number that multiplies result

Examples:
  ipc = instructions / cycles
  ipc/1 = instructions / cycles
  instructions / cycles

Currently only one metric can be passed to perf stat command.
The code facilitates the current metric code.

Link: https://lkml.kernel.org/n/tip-oe1ke93t9x9uc1hy0iueksqq@xxxxxxxxxxxxxx
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
 tools/perf/Documentation/perf-stat.txt | 16 ++++++++++
 tools/perf/builtin-stat.c              | 21 +++++++++++++
 tools/perf/util/metricgroup.c          | 43 ++++++++++++++++++++++++++
 tools/perf/util/metricgroup.h          |  2 ++
 4 files changed, 82 insertions(+)

diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
index 9431b8066fb4..6a76faec91f1 100644
--- a/tools/perf/Documentation/perf-stat.txt
+++ b/tools/perf/Documentation/perf-stat.txt
@@ -264,6 +264,22 @@ For a group all metrics from the group are added.
 The events from the metrics are automatically measured.
 See perf list output for the possble metrics and metricgroups.
 
+--metric::
+Print metric specified by the argument, where argument is defined as:
+
+  [name[/unit]=]expression
+
+  where:
+    name - is string that will identify expression in results
+           (can't have = or /) default is "user metric"
+    unit - is conversion number that multiplies result
+           default is 1
+
+  Examples:
+      ipc = instructions / cycles
+      ipc/1 = instructions / cycles
+      instructions / cycles
+
 -A::
 --no-aggr::
 Do not aggregate counts across all monitored CPUs.
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index a098c2ebf4ea..206df6f1cc8a 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -161,6 +161,7 @@ static bool			append_file;
 static bool			interval_count;
 static const char		*output_name;
 static int			output_fd;
+static char			*user_metric;
 
 struct perf_stat {
 	bool			 record;
@@ -841,6 +842,22 @@ static int parse_metric_groups(const struct option *opt,
 	return metricgroup__parse_groups(opt, str, &stat_config.metric_events);
 }
 
+static int parse_metric_expr(const struct option *opt,
+			     const char *str,
+			     int unset __maybe_unused)
+{
+	if (user_metric) {
+		pr_err("Only one user metric is currently supported.\n");
+		return -EINVAL;
+	}
+
+	user_metric = strdup(str);
+	if (!user_metric)
+		return -ENOMEM;
+
+	return metricgroup__parse_expr(opt, user_metric, &stat_config.metric_events);
+}
+
 static struct option stat_options[] = {
 	OPT_BOOLEAN('T', "transaction", &transaction_run,
 		    "hardware transaction statistics"),
@@ -923,6 +940,9 @@ static struct option stat_options[] = {
 	OPT_CALLBACK('M', "metrics", &evsel_list, "metric/metric group list",
 		     "monitor specified metrics or metric groups (separated by ,)",
 		     parse_metric_groups),
+	OPT_CALLBACK('m', "metric", &evsel_list, "metric expression",
+		     "monitor specified metric expression ([name/unit=]expression)",
+		     parse_metric_expr),
 	OPT_BOOLEAN_FLAG(0, "all-kernel", &stat_config.all_kernel,
 			 "Configure all used events to run in kernel space.",
 			 PARSE_OPT_EXCLUSIVE),
@@ -2184,6 +2204,7 @@ int cmd_stat(int argc, const char **argv)
 	perf_evlist__free_stats(evsel_list);
 out:
 	zfree(&stat_config.walltime_run);
+	zfree(&user_metric);
 
 	if (smi_cost && smi_reset)
 		sysfs__write_int(FREEZE_ON_SMI_PATH, 0);
diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
index abcfa3c1b4d5..c85be0ad8227 100644
--- a/tools/perf/util/metricgroup.c
+++ b/tools/perf/util/metricgroup.c
@@ -563,6 +563,49 @@ int metricgroup__parse_groups(const struct option *opt,
 	return ret;
 }
 
+int metricgroup__parse_expr(const struct option *opt, char *str,
+			    struct rblist *metric_events)
+{
+	struct evlist *perf_evlist = *(struct evlist **)opt->value;
+	char *tok, *expr, *unit = NULL;
+	struct strbuf extra_events;
+	LIST_HEAD(group_list);
+	const char *name;
+	int ret;
+
+	/*
+	 * user metric is passed as following argument:
+	 *   [name[/unit]=]expression
+	 */
+	tok = strchr(str, '=');
+	if (tok) {
+		*tok++ = 0;
+		name = str;
+		expr = tok;
+
+		tok = strchr(name, '/');
+		if (tok) {
+			*tok++ = 0;
+			unit = tok;
+		}
+	} else {
+		expr = str;
+		name = "user metric";
+	}
+
+	strbuf_init(&extra_events, 100);
+
+	ret = add_metric(name, expr, unit, &extra_events, &group_list);
+	if (ret)
+		return ret;
+
+	ret = metricgroup__setup(perf_evlist, metric_events, &extra_events,
+				 &group_list);
+	strbuf_release(&extra_events);
+	metricgroup__free_egroups(&group_list);
+	return ret;
+}
+
 bool metricgroup__has_metric(const char *metric)
 {
 	struct pmu_events_map *map = perf_pmu__find_map(NULL);
diff --git a/tools/perf/util/metricgroup.h b/tools/perf/util/metricgroup.h
index 475c7f912864..b66546b3ce1c 100644
--- a/tools/perf/util/metricgroup.h
+++ b/tools/perf/util/metricgroup.h
@@ -30,6 +30,8 @@ struct metric_event *metricgroup__lookup(struct rblist *metric_events,
 int metricgroup__parse_groups(const struct option *opt,
 			const char *str,
 			struct rblist *metric_events);
+int metricgroup__parse_expr(const struct option *opt, char *str,
+			    struct rblist *metric_events);
 
 void metricgroup__print(bool metrics, bool groups, char *filter,
 			bool raw, bool details);
-- 
2.21.1