perf metric: Modify resolution and recursion check

Modify resolution. Rather than resolving a list of metrics, resolve a
metric immediately after it is added.

This simplifies knowing the root of the metric's tree so that IDs may be
associated with it.

A bug in the current implementation is that all the IDs were placed on
the first metric in a metric group.

Rather than maintain data on IDs' parents to detect cycles, maintain
a list of visited metrics and detect cycles if the same metric is
visited twice.

Only place the root metric onto the list of metrics.
Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Antonov <alexander.antonov@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Kilroy <andrew.kilroy@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Changbin Du <changbin.du@intel.com>
Cc: Denys Zagorui <dzagorui@cisco.com>
Cc: Fabian Hemmer <copy@copy.sh>
Cc: Felix Fietkau <nbd@nbd.name>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jacob Keller <jacob.e.keller@intel.com>
Cc: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joakim Zhang <qiangqing.zhang@nxp.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Kees Kook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nicholas Fraser <nfraser@codeweavers.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: ShihCheng Tu <mrtoastcheng@gmail.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Wan Jiabing <wanjiabing@vivo.com>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20211015172132.1162559-10-irogers@google.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/expr.c

@@ -24,8 +24,8 @@ static int test_ids_union(void)
 	ids2 = ids__new();
 	TEST_ASSERT_VAL("ids__new", ids2);
 
-	TEST_ASSERT_EQUAL("ids__insert", ids__insert(ids1, strdup("foo"), NULL), 0);
-	TEST_ASSERT_EQUAL("ids__insert", ids__insert(ids1, strdup("bar"), NULL), 0);
+	TEST_ASSERT_EQUAL("ids__insert", ids__insert(ids1, strdup("foo")), 0);
+	TEST_ASSERT_EQUAL("ids__insert", ids__insert(ids1, strdup("bar")), 0);
 
 	ids1 = ids__union(ids1, ids2);
 	TEST_ASSERT_EQUAL("union", (int)hashmap__size(ids1), 2);
@@ -33,7 +33,7 @@ static int test_ids_union(void)
 	/* Union {foo, bar} against {foo}. */
 	ids2 = ids__new();
 	TEST_ASSERT_VAL("ids__new", ids2);
-	TEST_ASSERT_EQUAL("ids__insert", ids__insert(ids2, strdup("foo"), NULL), 0);
+	TEST_ASSERT_EQUAL("ids__insert", ids__insert(ids2, strdup("foo")), 0);
 
 	ids1 = ids__union(ids1, ids2);
 	TEST_ASSERT_EQUAL("union", (int)hashmap__size(ids1), 2);
@@ -41,8 +41,8 @@ static int test_ids_union(void)
 	/* Union {foo, bar} against {bar,baz}. */
 	ids2 = ids__new();
 	TEST_ASSERT_VAL("ids__new", ids2);
-	TEST_ASSERT_EQUAL("ids__insert", ids__insert(ids2, strdup("bar"), NULL), 0);
-	TEST_ASSERT_EQUAL("ids__insert", ids__insert(ids2, strdup("baz"), NULL), 0);
+	TEST_ASSERT_EQUAL("ids__insert", ids__insert(ids2, strdup("bar")), 0);
+	TEST_ASSERT_EQUAL("ids__insert", ids__insert(ids2, strdup("baz")), 0);
 
 	ids1 = ids__union(ids1, ids2);
 	TEST_ASSERT_EQUAL("union", (int)hashmap__size(ids1), 3);

tools/perf/util/expr.c

@@ -25,7 +25,6 @@ struct expr_id_data {
 			const char *metric_name;
 			const char *metric_expr;
 		} ref;
-		struct expr_id	*parent;
 	};
 
 	enum {
@@ -35,8 +34,6 @@ struct expr_id_data {
 		EXPR_ID_DATA__REF,
 		/* A reference but the value has been computed. */
 		EXPR_ID_DATA__REF_VALUE,
-		/* A parent is remembered for the recursion check. */
-		EXPR_ID_DATA__PARENT,
 	} kind;
 };
 
@@ -80,20 +77,12 @@ void ids__free(struct hashmap *ids)
 	hashmap__free(ids);
 }
 
-int ids__insert(struct hashmap *ids, const char *id,
-		struct expr_id *parent)
+int ids__insert(struct hashmap *ids, const char *id)
 {
 	struct expr_id_data *data_ptr = NULL, *old_data = NULL;
 	char *old_key = NULL;
 	int ret;
 
-	data_ptr = malloc(sizeof(*data_ptr));
-	if (!data_ptr)
-		return -ENOMEM;
-
-	data_ptr->parent = parent;
-	data_ptr->kind = EXPR_ID_DATA__PARENT;
-
 	ret = hashmap__set(ids, id, data_ptr,
 			   (const void **)&old_key, (void **)&old_data);
 	if (ret)
@@ -142,7 +131,7 @@ struct hashmap *ids__union(struct hashmap *ids1, struct hashmap *ids2)
 /* Caller must make sure id is allocated */
 int expr__add_id(struct expr_parse_ctx *ctx, const char *id)
 {
-	return ids__insert(ctx->ids, id, ctx->parent);
+	return ids__insert(ctx->ids, id);
 }
 
 /* Caller must make sure id is allocated */
@@ -238,9 +227,6 @@ int expr__resolve_id(struct expr_parse_ctx *ctx, const char *id,
 	case EXPR_ID_DATA__VALUE:
 		pr_debug2("lookup(%s): val %f\n", id, data->val);
 		break;
-	case EXPR_ID_DATA__PARENT:
-		pr_debug2("lookup(%s): parent %s\n", id, data->parent->id);
-		break;
 	case EXPR_ID_DATA__REF:
 		pr_debug2("lookup(%s): ref metric name %s\n", id,
 			data->ref.metric_name);
@@ -283,8 +269,8 @@ struct expr_parse_ctx *expr__ctx_new(void)
 		return NULL;
 
 	ctx->ids = hashmap__new(key_hash, key_equal, NULL);
-	ctx->parent = NULL;
 	ctx->runtime = 0;
+
 	return ctx;
 }
 
@@ -369,9 +355,3 @@ double expr_id_data__value(const struct expr_id_data *data)
 	assert(data->kind == EXPR_ID_DATA__REF_VALUE);
 	return data->ref.val;
 }
-
-struct expr_id *expr_id_data__parent(struct expr_id_data *data)
-{
-	assert(data->kind == EXPR_ID_DATA__PARENT);
-	return data->parent;
-}

tools/perf/util/expr.h

@@ -13,14 +13,8 @@
 
 struct metric_ref;
 
-struct expr_id {
-	char		*id;
-	struct expr_id	*parent;
-};
-
 struct expr_parse_ctx {
 	struct hashmap	*ids;
-	struct expr_id	*parent;
 	int runtime;
 };
 
@@ -32,7 +26,7 @@ struct expr_scanner_ctx {
 
 struct hashmap *ids__new(void);
 void ids__free(struct hashmap *ids);
-int ids__insert(struct hashmap *ids, const char *id, struct expr_id *parent);
+int ids__insert(struct hashmap *ids, const char *id);
 /*
  * Union two sets of ids (hashmaps) and construct a third, freeing ids1 and
  * ids2.
@@ -59,6 +53,5 @@ int expr__find_ids(const char *expr, const char *one,
 		   struct expr_parse_ctx *ids);
 
 double expr_id_data__value(const struct expr_id_data *data);
-struct expr_id *expr_id_data__parent(struct expr_id_data *data);
 
 #endif

tools/perf/util/expr.y

@@ -190,7 +190,7 @@ expr: NUMBER
 		 */
 		$$.val = BOTTOM;
 		$$.ids = ids__new();
-		if (!$$.ids || ids__insert($$.ids, $1, ctx->parent))
+		if (!$$.ids || ids__insert($$.ids, $1))
 			YYABORT;
 	}
 }