perf tools: Copy metric events properly when expand cgroups

The metricgroup__copy_metric_events() is to handle metrics events when
expanding event for cgroups.  As the metric events keep pointers to
evsel, it should be refreshed when events are cloned during the
operation.

The perf_stat__collect_metric_expr() is also called in case an event has
a metric directly.

During the copy, it references evsel by index as the evlist now has
cloned evsels for the given cgroup.

Also kernel test robot found an issue in the python module import so add
empty implementations of those two functions to fix it.

Reported-by: kernel test robot <rong.a.chen@intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20200924124455.336326-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-stat.c

@@ -2234,7 +2234,8 @@ int cmd_stat(int argc, const char **argv)
 			goto out;
 		}
 
-		if (evlist__expand_cgroup(evsel_list, stat_config.cgroup_list) < 0)
+		if (evlist__expand_cgroup(evsel_list, stat_config.cgroup_list,
+					  &stat_config.metric_events) < 0)
 			goto out;
 	}
 

tools/perf/util/cgroup.c

@@ -3,6 +3,9 @@
 #include "evsel.h"
 #include "cgroup.h"
 #include "evlist.h"
+#include "rblist.h"
+#include "metricgroup.h"
+#include "stat.h"
 #include <linux/zalloc.h>
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -193,10 +196,12 @@ int parse_cgroups(const struct option *opt, const char *str,
 	return 0;
 }
 
-int evlist__expand_cgroup(struct evlist *evlist, const char *str)
+int evlist__expand_cgroup(struct evlist *evlist, const char *str,
+			  struct rblist *metric_events)
 {
 	struct evlist *orig_list, *tmp_list;
 	struct evsel *pos, *evsel, *leader;
+	struct rblist orig_metric_events;
 	struct cgroup *cgrp = NULL;
 	const char *p, *e, *eos = str + strlen(str);
 	int ret = -1;
@@ -217,6 +222,13 @@ int evlist__expand_cgroup(struct evlist *evlist, const char *str)
 	perf_evlist__splice_list_tail(orig_list, &evlist->core.entries);
 	evlist->core.nr_entries = 0;
 
+	if (metric_events) {
+		orig_metric_events = *metric_events;
+		rblist__init(metric_events);
+	} else {
+		rblist__init(&orig_metric_events);
+	}
+
 	for (;;) {
 		p = strchr(str, ',');
 		e = p ? p : eos;
@@ -255,6 +267,14 @@ int evlist__expand_cgroup(struct evlist *evlist, const char *str)
 		cgroup__put(cgrp);
 		nr_cgroups++;
 
+		if (metric_events) {
+			perf_stat__collect_metric_expr(tmp_list);
+			if (metricgroup__copy_metric_events(tmp_list, cgrp,
+							    metric_events,
+							    &orig_metric_events) < 0)
+				break;
+		}
+
 		perf_evlist__splice_list_tail(evlist, &tmp_list->core.entries);
 		tmp_list->core.nr_entries = 0;
 
@@ -268,6 +288,7 @@ int evlist__expand_cgroup(struct evlist *evlist, const char *str)
 out_err:
 	evlist__delete(orig_list);
 	evlist__delete(tmp_list);
+	rblist__exit(&orig_metric_events);
 
 	return ret;
 }

tools/perf/util/cgroup.h

@@ -22,9 +22,11 @@ struct cgroup *cgroup__get(struct cgroup *cgroup);
 void cgroup__put(struct cgroup *cgroup);
 
 struct evlist;
+struct rblist;
 
 struct cgroup *evlist__findnew_cgroup(struct evlist *evlist, const char *name);
-int evlist__expand_cgroup(struct evlist *evlist, const char *cgroups);
+int evlist__expand_cgroup(struct evlist *evlist, const char *cgroups,
+			  struct rblist *metric_events);
 
 void evlist__set_default_cgroup(struct evlist *evlist, struct cgroup *cgroup);
 

tools/perf/util/evlist.c

@@ -1969,3 +1969,14 @@ int evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd)
 
 	return err;
 }
+
+struct evsel *evlist__find_evsel(struct evlist *evlist, int idx)
+{
+	struct evsel *evsel;
+
+	evlist__for_each_entry(evlist, evsel) {
+		if (evsel->idx == idx)
+			return evsel;
+	}
+	return NULL;
+}

tools/perf/util/evlist.h

@@ -386,4 +386,5 @@ int evlist__ctlfd_ack(struct evlist *evlist);
 #define EVLIST_ENABLED_MSG "Events enabled\n"
 #define EVLIST_DISABLED_MSG "Events disabled\n"
 
+struct evsel *evlist__find_evsel(struct evlist *evlist, int idx);
 #endif /* __PERF_EVLIST_H */

tools/perf/util/metricgroup.c

@@ -24,6 +24,7 @@
 #include <api/fs/fs.h>
 #include "util.h"
 #include <asm/bug.h>
+#include "cgroup.h"
 
 struct metric_event *metricgroup__lookup(struct rblist *metric_events,
 					 struct evsel *evsel,
@@ -1120,3 +1121,87 @@ bool metricgroup__has_metric(const char *metric)
 	}
 	return false;
 }
+
+int metricgroup__copy_metric_events(struct evlist *evlist, struct cgroup *cgrp,
+				    struct rblist *new_metric_events,
+				    struct rblist *old_metric_events)
+{
+	unsigned i;
+
+	for (i = 0; i < rblist__nr_entries(old_metric_events); i++) {
+		struct rb_node *nd;
+		struct metric_event *old_me, *new_me;
+		struct metric_expr *old_expr, *new_expr;
+		struct evsel *evsel;
+		size_t alloc_size;
+		int idx, nr;
+
+		nd = rblist__entry(old_metric_events, i);
+		old_me = container_of(nd, struct metric_event, nd);
+
+		evsel = evlist__find_evsel(evlist, old_me->evsel->idx);
+		if (!evsel)
+			return -EINVAL;
+		new_me = metricgroup__lookup(new_metric_events, evsel, true);
+		if (!new_me)
+			return -ENOMEM;
+
+		pr_debug("copying metric event for cgroup '%s': %s (idx=%d)\n",
+			 cgrp ? cgrp->name : "root", evsel->name, evsel->idx);
+
+		list_for_each_entry(old_expr, &old_me->head, nd) {
+			new_expr = malloc(sizeof(*new_expr));
+			if (!new_expr)
+				return -ENOMEM;
+
+			new_expr->metric_expr = old_expr->metric_expr;
+			new_expr->metric_name = old_expr->metric_name;
+			new_expr->metric_unit = old_expr->metric_unit;
+			new_expr->runtime = old_expr->runtime;
+
+			if (old_expr->metric_refs) {
+				/* calculate number of metric_events */
+				for (nr = 0; old_expr->metric_refs[nr].metric_name; nr++)
+					continue;
+				alloc_size = sizeof(*new_expr->metric_refs);
+				new_expr->metric_refs = calloc(nr + 1, alloc_size);
+				if (!new_expr->metric_refs) {
+					free(new_expr);
+					return -ENOMEM;
+				}
+
+				memcpy(new_expr->metric_refs, old_expr->metric_refs,
+				       nr * alloc_size);
+			} else {
+				new_expr->metric_refs = NULL;
+			}
+
+			/* calculate number of metric_events */
+			for (nr = 0; old_expr->metric_events[nr]; nr++)
+				continue;
+			alloc_size = sizeof(*new_expr->metric_events);
+			new_expr->metric_events = calloc(nr + 1, alloc_size);
+			if (!new_expr->metric_events) {
+				free(new_expr->metric_refs);
+				free(new_expr);
+				return -ENOMEM;
+			}
+
+			/* copy evsel in the same position */
+			for (idx = 0; idx < nr; idx++) {
+				evsel = old_expr->metric_events[idx];
+				evsel = evlist__find_evsel(evlist, evsel->idx);
+				if (evsel == NULL) {
+					free(new_expr->metric_events);
+					free(new_expr->metric_refs);
+					free(new_expr);
+					return -EINVAL;
+				}
+				new_expr->metric_events[idx] = evsel;
+			}
+
+			list_add(&new_expr->nd, &new_me->head);
+		}
+	}
+	return 0;
+}

tools/perf/util/metricgroup.h

@@ -7,11 +7,13 @@
 #include <stdbool.h>
 #include "pmu-events/pmu-events.h"
 
+struct evlist;
 struct evsel;
 struct evlist;
 struct option;
 struct rblist;
 struct pmu_events_map;
+struct cgroup;
 
 struct metric_event {
 	struct rb_node nd;
@@ -55,4 +57,8 @@ void metricgroup__print(bool metrics, bool groups, char *filter,
 bool metricgroup__has_metric(const char *metric);
 int arch_get_runtimeparam(struct pmu_event *pe __maybe_unused);
 void metricgroup__rblist_exit(struct rblist *metric_events);
+
+int metricgroup__copy_metric_events(struct evlist *evlist, struct cgroup *cgrp,
+				    struct rblist *new_metric_events,
+				    struct rblist *old_metric_events);
 #endif

tools/perf/util/python.c

@@ -15,6 +15,8 @@
 #include "thread_map.h"
 #include "trace-event.h"
 #include "mmap.h"
+#include "stat.h"
+#include "metricgroup.h"
 #include "util/env.h"
 #include <internal/lib.h>
 #include "util.h"
@@ -60,6 +62,23 @@ int parse_callchain_record(const char *arg __maybe_unused,
  */
 struct perf_env perf_env;
 
+/*
+ * Add this one here not to drag util/stat-shadow.c
+ */
+void perf_stat__collect_metric_expr(struct evlist *evsel_list)
+{
+}
+
+/*
+ * Add this one here not to drag util/metricgroup.c
+ */
+int metricgroup__copy_metric_events(struct evlist *evlist, struct cgroup *cgrp,
+				    struct rblist *new_metric_events,
+				    struct rblist *old_metric_events)
+{
+	return 0;
+}
+
 /*
  * Support debug printing even though util/debug.c is not linked.  That means
  * implementing 'verbose' and 'eprintf'.