perf stat: Add transaction flag (-T) support for s390

The 'perf stat' command line flag -T to display transaction counters is
currently supported for x86 only.

Add support for s390. It is based on the metrics flag -M transaction
using the architecture dependent JSON files. This requires a metric
named "transaction" in the JSON files for the platform.

Introduce a new function metricgroup__has_metric() to check for the
existence of a metric_name transaction.

As suggested by Andi Kleen, this is the new approach to support
transactions counters. Other architectures will follow.

Output before:

[root@p23lp27 perf]# ./perf stat -T -- sleep 1
Cannot set up transaction events
[root@p23lp27 perf]#

Output after:

[root@s35lp76 perf]# ./perf stat -T -- ~/mytesttx 1 >/tmp/111

Performance counter stats for '/root/mytesttx 1':

1 tx_c_tend # 13.0 transaction
1 tx_nc_tend
11 tx_nc_tabort
0 tx_c_tabort_special
0 tx_c_tabort_no_special

0.001070109 seconds time elapsed

[root@s35lp76 perf]#

Suggested-by: Andi Kleen <[e-mail]>
Signed-off-by: Thomas Richter <[e-mail]>
Reviewed-by: Hendrik Brueckner <[e-mail]>
Acked-by: Andi Kleen <[e-mail]>
Acked-by: Jiri Olsa <[e-mail]>
Cc: Heiko Carstens <[e-mail]>
Cc: Martin Schwidefsky <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/builtin-stat.c

···
 		return 0;
 
 	if (transaction_run) {
+		/* Handle -T as -M transaction. Once platform specific metrics
+		 * support has been added to the json files, all archictures
+		 * will use this approach. To determine transaction support
+		 * on an architecture test for such a metric name.
+		 */
+		if (metricgroup__has_metric("transaction")) {
+			struct option opt = { .value = &evsel_list };
+
+			return metricgroup__parse_groups(&opt, "transaction",
+							 &metric_events);
+		}
+
 		if (pmu_have_event("cpu", "cycles-ct") &&
 		    pmu_have_event("cpu", "el-start"))
 			err = parse_events(evsel_list, transaction_attrs,

tools/perf/util/metricgroup.c

···
 	metricgroup__free_egroups(&group_list);
 	return ret;
 }
+
+bool metricgroup__has_metric(const char *metric)
+{
+	struct pmu_events_map *map = perf_pmu__find_map(NULL);
+	struct pmu_event *pe;
+	int i;
+
+	if (!map)
+		return false;
+
+	for (i = 0; ; i++) {
+		pe = &map->table[i];
+
+		if (!pe->name && !pe->metric_group && !pe->metric_name)
+			break;
+		if (!pe->metric_expr)
+			continue;
+		if (match_metric(pe->metric_name, metric))
+			return true;
+	}
+	return false;
+}

tools/perf/util/metricgroup.h

···
 			struct rblist *metric_events);
 
 void metricgroup__print(bool metrics, bool groups, char *filter, bool raw);
+bool metricgroup__has_metric(const char *metric);
 #endif