table: add entry ID for learner tables

Add support for unique ID for each learner table entry. The entry ID
is retrieved as part of the learner table lookup operation and is
saved by the pipeline for later use.

Signed-off-by: Cristian Dumitrescu <cristian.dumitrescu@intel.com>

lib/pipeline/rte_swx_pipeline.c

@@ -2556,6 +2556,7 @@ instr_learner_exec(struct rte_swx_pipeline *p)
 	struct learner_statistics *stats = &p->learner_stats[learner_id];
 	uint64_t action_id, n_pkts_hit, n_pkts_action, time;
 	uint8_t *action_data;
+	size_t entry_id;
 	int done, hit;
 
 	/* Table. */
@@ -2567,6 +2568,7 @@ instr_learner_exec(struct rte_swx_pipeline *p)
 					    l->key,
 					    &action_id,
 					    &action_data,
+					    &entry_id,
 					    &hit);
 	if (!done) {
 		/* Thread. */
@@ -2580,6 +2582,7 @@ instr_learner_exec(struct rte_swx_pipeline *p)
 
 	action_id = hit ? action_id : ts->default_action_id;
 	action_data = hit ? action_data : ts->default_action_data;
+	entry_id = hit ? (1 + entry_id) : 0;
 	n_pkts_hit = stats->n_pkts_hit[hit];
 	n_pkts_action = stats->n_pkts_action[action_id];
 
@@ -2591,6 +2594,7 @@ instr_learner_exec(struct rte_swx_pipeline *p)
 
 	t->action_id = action_id;
 	t->structs[0] = action_data;
+	t->entry_id = entry_id;
 	t->hit = hit;
 	t->learner_id = learner_id;
 	t->time = time;
@@ -2613,6 +2617,7 @@ instr_learner_af_exec(struct rte_swx_pipeline *p)
 	struct learner_statistics *stats = &p->learner_stats[learner_id];
 	uint64_t action_id, n_pkts_hit, n_pkts_action, time;
 	uint8_t *action_data;
+	size_t entry_id;
 	action_func_t action_func;
 	int done, hit;
 
@@ -2625,6 +2630,7 @@ instr_learner_af_exec(struct rte_swx_pipeline *p)
 					    l->key,
 					    &action_id,
 					    &action_data,
+					    &entry_id,
 					    &hit);
 	if (!done) {
 		/* Thread. */
@@ -2638,6 +2644,7 @@ instr_learner_af_exec(struct rte_swx_pipeline *p)
 
 	action_id = hit ? action_id : ts->default_action_id;
 	action_data = hit ? action_data : ts->default_action_data;
+	entry_id = hit ? (1 + entry_id) : 0;
 	action_func = p->action_funcs[action_id];
 	n_pkts_hit = stats->n_pkts_hit[hit];
 	n_pkts_action = stats->n_pkts_action[action_id];
@@ -2650,6 +2657,7 @@ instr_learner_af_exec(struct rte_swx_pipeline *p)
 
 	t->action_id = action_id;
 	t->structs[0] = action_data;
+	t->entry_id = entry_id;
 	t->hit = hit;
 	t->learner_id = learner_id;
 	t->time = time;

lib/table/rte_swx_table_learner.c

@@ -72,6 +72,7 @@ table_keycpy(void *dst, void *src, uint32_t n_bytes)
 }
 
 #define TABLE_KEYS_PER_BUCKET 4
+#define TABLE_KEYS_PER_BUCKET_LOG2 2
 
 #define TABLE_BUCKET_USEFUL_SIZE \
 	(TABLE_KEYS_PER_BUCKET * (sizeof(uint32_t) + sizeof(uint32_t) + sizeof(uint8_t)))
@@ -263,6 +264,14 @@ table_bucket_data_get(struct table *t, struct table_bucket *b, size_t bucket_key
 				   (bucket_key_pos << t->params.data_size_log2)];
 }
 
+static inline size_t
+table_entry_id_get(struct table *t, struct table_bucket *b, size_t bucket_key_pos)
+{
+	size_t bucket_id = ((uint8_t *)b - t->buckets) >> t->params.bucket_size_log2;
+
+	return (bucket_id << TABLE_KEYS_PER_BUCKET_LOG2) + bucket_key_pos;
+}
+
 uint64_t
 rte_swx_table_learner_footprint_get(struct rte_swx_table_learner_params *params)
 {
@@ -332,7 +341,7 @@ struct mailbox {
 	/* Writer: lookup state 0. Reader(s): lookup state 1, add(). */
 	uint32_t input_sig;
 
-	/* Writer: lookup state 1. Reader(s): add(). */
+	/* Writer: lookup state 0. Reader(s): lookup state 1, add(). */
 	uint8_t *input_key;
 
 	/* Writer: lookup state 1. Reader(s): add(). Values: 0 = miss; 1 = hit. */
@@ -358,6 +367,7 @@ rte_swx_table_learner_lookup(void *table,
 			     uint8_t **key,
 			     uint64_t *action_id,
 			     uint8_t **action_data,
+			     size_t *entry_id,
 			     int *hit)
 {
 	struct table *t = table;
@@ -412,6 +422,7 @@ rte_swx_table_learner_lookup(void *table,
 
 				*action_id = data[0];
 				*action_data = (uint8_t *)&data[1];
+				*entry_id = table_entry_id_get(t, b, i);
 				*hit = 1;
 				return 1;
 			}

lib/table/rte_swx_table_learner.h

@@ -47,6 +47,7 @@ extern "C" {
  */
 
 #include <stdint.h>
+#include <sys/types.h>
 
 #include <rte_compat.h>
 
@@ -173,6 +174,14 @@ rte_swx_table_learner_timeout_update(void *table,
  * possibly an associated key add operation. The mailbox mechanism allows for multiple concurrent
  * table key lookup and add operations into the same table.
  *
+ * The table entry consists of the action ID and the action data. Each table entry is unique, even
+ * though different table entries can have identical content, i.e. same values for the action ID and
+ * the action data. The table entry ID is also returned by the table lookup operation. It can be
+ * used to index into an external array of resources such as counters, registers or meters to
+ * identify the resource directly associated with the current table entry with no need to store the
+ * corresponding index into the table entry. The index of the external resource is thus
+ * auto-generated instead of being stored in the table entry.
+ *
  * @param[in] table
  *   Table handle.
  * @param[in] mailbox
@@ -187,6 +196,9 @@ rte_swx_table_learner_timeout_update(void *table,
  * @param[out] action_data
  *   Action data for the *action_id* action. Must point to a valid array of table *action_data_size*
  *   bytes. Only valid when the function returns 1 and *hit* is set to true.
+ * @param[out] entry_id
+ *   Table entry unique ID. Must point to a valid 32-bit variable. Only valid when the function
+ *   returns 1 and *hit* is set to true.
  * @param[out] hit
  *   Only valid when the function returns 1. Set to non-zero (true) on table lookup hit and to zero
  *   (false) on table lookup miss.
@@ -202,6 +214,7 @@ rte_swx_table_learner_lookup(void *table,
 			     uint8_t **key,
 			     uint64_t *action_id,
 			     uint8_t **action_data,
+			     size_t *entry_id,
 			     int *hit);
 
 /**