[RFC PATCH v2 07/17] perf stat: Add functions to set counter bitmaps for hardware-grouping method

[weilin . wang]

From: Weilin Wang <weilin.wang@xxxxxxxxx>

Add metricgroup__event_info data structure to represent an event in the
metric grouping context; the list of counters and the PMU name an event
should be collected with.

Add functions to parse event counter info from pmu-events and generate a
list of metricgroup__event_info data to prepare grouping.

Signed-off-by: Weilin Wang <weilin.wang@xxxxxxxxx>
---
 tools/perf/util/metricgroup.c | 196 +++++++++++++++++++++++++++++++++-
 tools/perf/util/metricgroup.h |  27 +++++
 2 files changed, 220 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
index 8d4e29eb1..6af8a7341 100644
--- a/tools/perf/util/metricgroup.c
+++ b/tools/perf/util/metricgroup.c
@@ -1432,6 +1432,182 @@ static int build_combined_expr_ctx(const struct list_head *metric_list,
 	return ret;
 }
 
+/**
+ * set_counter_bitmap - The counter bit mapping: [8-15,0-7], e.g. the GP0 is the
+ * 8th bit and GP7 is the 1st bit in this 16-bits bitmap. It is helpful for
+ * assigning GP4-7 before GP0-3 because some events can be collected using GP0-3
+ * only on some platforms.
+ */
+static int set_counter_bitmap(int pos, unsigned long *bitmap)
+{
+	if (pos >= NR_COUNTERS || pos < 0)
+		return -EINVAL;
+	if (pos <= 7)
+		pos = TRANSFER_FIRST_BYTE(pos);
+	else
+		pos = TRANSFER_SEC_BYTE(pos);
+	*bitmap |= 1ul << pos;
+	return 0;
+}
+
+static int parse_fixed_counter(const char *counter,
+			      unsigned long *bitmap,
+			      bool *fixed)
+{
+	int ret = -ENOENT;
+	//TODO: this pattern is different on some other platforms
+	const char *pattern = "Fixed counter ";
+	int pos = 0;
+
+	if (!strncmp(counter, pattern, strlen(pattern))) {
+		pos = atoi(counter + strlen(pattern));
+		ret = set_counter_bitmap(pos, bitmap);
+		if (ret)
+			return ret;
+		*fixed = true;
+		return 0;
+	}
+	return ret;
+}
+
+/**
+ * parse_counter - Parse event counter info from pmu-events and set up bitmap
+ * accordingly.
+ *
+ * @counter: counter info string to be parsed.
+ * @bitmap: bitmap to set based on counter info parsed.
+ * @fixed: is set to true if the event uses fixed counter.
+ */
+static int parse_counter(const char *counter,
+			unsigned long *bitmap,
+			bool *fixed)
+{
+	int ret = 0;
+	char *p;
+	char *tok;
+	int pos = 0;
+
+	ret = parse_fixed_counter(counter, bitmap, fixed);
+	// ret==0 means matched with fixed counter
+	if (ret == 0)
+		return ret;
+
+	p = strdup(counter);
+	tok = strtok(p, ",");
+	if (!tok)
+		return -ENOENT;
+
+	while (tok) {
+		pos = atoi(tok);
+		ret = set_counter_bitmap(pos, bitmap);
+		if (ret)
+			return ret;
+		tok = strtok(NULL, ",");
+	}
+	return 0;
+}
+
+static struct metricgroup__event_info *event_info__new(const char *name,
+						      const char *pmu_name,
+						      const char *counter,
+						      bool free_counter)
+{
+	int ret = 0;
+	char *bit_buf = malloc(NR_COUNTERS);
+	bool fixed_counter = false;
+	struct metricgroup__event_info *e;
+
+	e = zalloc(sizeof(*e));
+	if (!e)
+		return NULL;
+	if (!pmu_name)
+		pmu_name = "core";
+
+	e->name = name;
+	e->free_counter = free_counter;
+	e->pmu_name = strdup(pmu_name);
+	if (free_counter) {
+		ret = set_counter_bitmap(0, e->counters);
+		if (ret)
+			return NULL;
+	} else {
+		ret = parse_counter(counter, e->counters, &fixed_counter);
+		if (ret)
+			return NULL;
+		e->fixed_counter = fixed_counter;
+	}
+
+	bitmap_scnprintf(e->counters, NR_COUNTERS, bit_buf, NR_COUNTERS);
+	pr_debug("Event %s requires pmu %s counter: %s bitmap %s, [pmu=%s]\n",
+		e->name, e->pmu_name, counter, bit_buf, pmu_name);
+
+	return e;
+}
+
+struct metricgroup__add_metric_event_data {
+	struct list_head *list;
+	/* pure event name, exclude umask and other info*/
+	const char *event_name;
+	/* event name and umask if applicable*/
+	const char *event_id;
+};
+
+static int metricgroup__add_metric_event_callback(const struct pmu_event *pe,
+						 const struct pmu_events_table *table __maybe_unused,
+						 void *data)
+{
+	struct metricgroup__event_info *event;
+	struct metricgroup__add_metric_event_data *d = data;
+
+	if (!strcasecmp(pe->name, d->event_name)) {
+		event = event_info__new(d->event_id, pe->pmu, pe->counter, /*free_counter=*/false);
+		if (!event)
+			return -ENOMEM;
+		list_add(&event->nd, d->list);
+	}
+
+	return 0;
+}
+
+/**
+ * get_metricgroup_events - Find counter requirement of events from the
+ * pmu_events table
+ * @full_id: the full event identifiers.
+ * @table: pmu_events table that is searched for event data.
+ * @event_info_list: the list that the new event counter info added to.
+ */
+static int get_metricgroup_events(const char *full_id,
+				 const struct pmu_events_table *table,
+				 struct list_head *event_info_list)
+{
+	LIST_HEAD(list);
+	int ret = 0;
+	const char *id;
+	const char *rsep, *sep = strchr(full_id, '@');
+
+	if (sep) {
+		rsep = strchr(full_id, ',');
+		id = strndup(sep + 1, rsep - sep - 1);
+		if (ret)
+			goto out;
+	} else {
+		id = full_id;
+	}
+	{
+		struct metricgroup__add_metric_event_data data = {
+			.list = &list,
+			.event_name = id,
+			.event_id = full_id,
+		};
+		ret = pmu_events_table_for_each_event(table,
+				metricgroup__add_metric_event_callback, &data);
+	}
+
+out:
+	list_splice(&list, event_info_list);
+	return ret;
+}
+
 /**
  * hw_aware_build_grouping - Build event groupings by reading counter
  * requirement of the events and counter available on the system from
@@ -1445,9 +1621,25 @@ static int hw_aware_build_grouping(struct expr_parse_ctx *ctx __maybe_unused,
 				  const char *modifier __maybe_unused)
 {
 	int ret = 0;
+	struct hashmap_entry *cur;
+	LIST_HEAD(pmu_info_list);
+	LIST_HEAD(event_info_list);
+	size_t bkt;
+	const struct pmu_events_table *etable = pmu_events_table__find();
+
+#define RETURN_IF_NON_ZERO(x) do { if (x) return x; } while (0)
+	hashmap__for_each_entry(ctx->ids, cur, bkt) {
+		const char *id = cur->pkey;
+
+		pr_debug("found event %s\n", id);
+
+		ret = get_metricgroup_events(id, etable, &event_info_list);
+		if (ret)
+			return ret;
+	}
 
-	pr_debug("This is a placeholder\n");
 	return ret;
+#undef RETURN_IF_NON_ZERO
 }
 
 static void group_str_free(struct metricgroup__group_strs *g)
@@ -1521,8 +1713,6 @@ static int hw_aware_parse_ids(struct perf_pmu *fake_pmu,
 	*out_evlist = parsed_evlist;
 	parsed_evlist = NULL;
 err_out:
-	parse_events_error__exit(&parse_error);
-	evlist__delete(parsed_evlist);
 	metricgroup__free_grouping_strs(&groupings);
 	return ret;
 }
diff --git a/tools/perf/util/metricgroup.h b/tools/perf/util/metricgroup.h
index 89809df85..3704545c9 100644
--- a/tools/perf/util/metricgroup.h
+++ b/tools/perf/util/metricgroup.h
@@ -5,6 +5,7 @@
 #include <linux/list.h>
 #include <linux/rbtree.h>
 #include <stdbool.h>
+#include <linux/bitmap.h>
 #include "pmu-events/pmu-events.h"
 #include "strbuf.h"
 
@@ -67,6 +68,32 @@ struct metric_expr {
 	int runtime;
 };
 
+/* Maximum number of counters per PMU*/
+#define NR_COUNTERS	16
+/*
+ * Transfer bit position in the bitmap to ensure start assigning counter from
+ * the last GP counter to the first.
+ * bit15 <---> bit0
+ * [GP8-GP15] [GP0-GP7]
+ */
+#define TRANSFER_FIRST_BYTE(pos) (7 - pos)
+#define TRANSFER_SEC_BYTE(pos) (23 - pos)
+
+/**
+ * An event used in a metric. This info is for metric grouping.
+ */
+struct metricgroup__event_info {
+	struct list_head nd;
+	/** The name of the event. */
+	const char *name;
+	/** The name of the pmu the event be collected on. */
+	const char *pmu_name;
+	bool fixed_counter;
+	bool free_counter;
+	/** The counters the event allowed to be collected on. */
+	DECLARE_BITMAP(counters, NR_COUNTERS);
+};
+
 /**
  * Each group is one node in the group string list.
  */
-- 
2.39.3