@@ -7683,6 +7683,28 @@ dpif_dummy_register(enum dummy_level level)
/* Datapath Classifier. */
+/* Forward declaration for lookup_func typedef. */
+struct dpcls_subtable;
+
+/* Lookup function for a subtable in the dpcls. This function is called
+ * by each subtable with an array of packets, and a bitmask of packets to
+ * perform the lookup on. Using a function pointer gives flexibility to
+ * optimize the lookup function based on subtable properties and the
+ * CPU instruction set available at runtime.
+ */
+typedef
+uint32_t (*dpcls_subtable_lookup_func)(struct dpcls_subtable *subtable,
+ uint32_t keys_map,
+ const struct netdev_flow_key *keys[],
+ struct dpcls_rule **rules);
+
+/* Prototype for generic lookup func, using same code path as before. */
+uint32_t
+dpcls_subtable_lookup_generic(struct dpcls_subtable *subtable,
+ uint32_t keys_map,
+ const struct netdev_flow_key *keys[],
+ struct dpcls_rule **rules);
+
/* A set of rules that all have the same fields wildcarded. */
struct dpcls_subtable {
/* The fields are only used by writers. */
@@ -7692,6 +7714,13 @@ struct dpcls_subtable {
struct cmap rules; /* Contains "struct dpcls_rule"s. */
uint32_t hit_cnt; /* Number of match hits in subtable in current
optimization interval. */
+
+ /* The lookup function to use for this subtable. If there is a known
+ * property of the subtable (eg: only 3 bits of miniflow metadata is
+ * used for the lookup) then this can point at an optimized version of
+ * the lookup function for this particular subtable. */
+ dpcls_subtable_lookup_func lookup_func;
+
struct netdev_flow_key mask; /* Wildcards for fields (const). */
/* 'mask' must be the last field, additional space is allocated here. */
};
@@ -7751,6 +7780,10 @@ dpcls_create_subtable(struct dpcls *cls, const struct netdev_flow_key *mask)
cmap_init(&subtable->rules);
subtable->hit_cnt = 0;
netdev_flow_key_clone(&subtable->mask, mask);
+
+ /* Decide which hash/lookup/verify function to use. */
+ subtable->lookup_func = dpcls_subtable_lookup_generic;
+
cmap_insert(&cls->subtables_map, &subtable->cmap_node, mask->hash);
/* Add the new subtable at the end of the pvector (with no hits yet) */
pvector_insert(&cls->subtables, subtable, 0);
@@ -7911,6 +7944,55 @@ dpcls_rule_matches_key(const struct dpcls_rule *rule,
return true;
}
+uint32_t
+dpcls_subtable_lookup_generic(struct dpcls_subtable *subtable,
+ uint32_t keys_map,
+ const struct netdev_flow_key *keys[],
+ struct dpcls_rule **rules)
+{
+ int i;
+ uint32_t found_map;
+
+ /* Compute hashes for the remaining keys. Each search-key is
+ * masked with the subtable's mask to avoid hashing the wildcarded
+ * bits. */
+ uint32_t hashes[NETDEV_MAX_BURST];
+ ULLONG_FOR_EACH_1 (i, keys_map) {
+ hashes[i] = netdev_flow_key_hash_in_mask(keys[i],
+ &subtable->mask);
+ }
+
+ /* Lookup. */
+ const struct cmap_node *nodes[NETDEV_MAX_BURST];
+ found_map = cmap_find_batch(&subtable->rules, keys_map, hashes, nodes);
+
+ /* Check results. When the i-th bit of found_map is set, it means
+ * that a set of nodes with a matching hash value was found for the
+ * i-th search-key. Due to possible hash collisions we need to check
+ * which of the found rules, if any, really matches our masked
+ * search-key. */
+ ULLONG_FOR_EACH_1 (i, found_map) {
+ struct dpcls_rule *rule;
+
+ CMAP_NODE_FOR_EACH (rule, cmap_node, nodes[i]) {
+ if (OVS_LIKELY(dpcls_rule_matches_key(rule, keys[i]))) {
+ rules[i] = rule;
+ /* Even at 20 Mpps the 32-bit hit_cnt cannot wrap
+ * within one second optimization interval. */
+ subtable->hit_cnt++;
+ goto next;
+ }
+ }
+ /* None of the found rules was a match. Reset the i-th bit to
+ * keep searching this key in the next subtable. */
+ ULLONG_SET0(found_map, i); /* Did not match. */
+ next:
+ ; /* Keep Sparse happy. */
+ }
+
+ return found_map;
+}
+
/* For each miniflow in 'keys' performs a classifier lookup writing the result
* into the corresponding slot in 'rules'. If a particular entry in 'keys' is
* NULL it is skipped.
@@ -7929,16 +8011,12 @@ dpcls_lookup(struct dpcls *cls, const struct netdev_flow_key *keys[],
/* The received 'cnt' miniflows are the search-keys that will be processed
* to find a matching entry into the available subtables.
* The number of bits in map_type is equal to NETDEV_MAX_BURST. */
- typedef uint32_t map_type;
-#define MAP_BITS (sizeof(map_type) * CHAR_BIT)
+#define MAP_BITS (sizeof(uint32_t) * CHAR_BIT)
BUILD_ASSERT_DECL(MAP_BITS >= NETDEV_MAX_BURST);
struct dpcls_subtable *subtable;
- map_type keys_map = TYPE_MAXIMUM(map_type); /* Set all bits. */
- map_type found_map;
- uint32_t hashes[MAP_BITS];
- const struct cmap_node *nodes[MAP_BITS];
+ uint32_t keys_map = TYPE_MAXIMUM(uint32_t); /* Set all bits. */
if (cnt != MAP_BITS) {
keys_map >>= MAP_BITS - cnt; /* Clear extra bits. */
@@ -7946,6 +8024,7 @@ dpcls_lookup(struct dpcls *cls, const struct netdev_flow_key *keys[],
memset(rules, 0, cnt * sizeof *rules);
int lookups_match = 0, subtable_pos = 1;
+ uint32_t found_map;
/* The Datapath classifier - aka dpcls - is composed of subtables.
* Subtables are dynamically created as needed when new rules are inserted.
@@ -7955,52 +8034,27 @@ dpcls_lookup(struct dpcls *cls, const struct netdev_flow_key *keys[],
* search-key, the search for that key can stop because the rules are
* non-overlapping. */
PVECTOR_FOR_EACH (subtable, &cls->subtables) {
- int i;
+ /* Call the subtable specific lookup function. */
+ found_map = subtable->lookup_func(subtable, keys_map, keys, rules);
- /* Compute hashes for the remaining keys. Each search-key is
- * masked with the subtable's mask to avoid hashing the wildcarded
- * bits. */
- ULLONG_FOR_EACH_1(i, keys_map) {
- hashes[i] = netdev_flow_key_hash_in_mask(keys[i],
- &subtable->mask);
- }
- /* Lookup. */
- found_map = cmap_find_batch(&subtable->rules, keys_map, hashes, nodes);
- /* Check results. When the i-th bit of found_map is set, it means
- * that a set of nodes with a matching hash value was found for the
- * i-th search-key. Due to possible hash collisions we need to check
- * which of the found rules, if any, really matches our masked
- * search-key. */
- ULLONG_FOR_EACH_1(i, found_map) {
- struct dpcls_rule *rule;
+ /* Count the number of subtables searched for this packet match. This
+ * estimates the "spread" of subtables looked at per matched packet. */
+ uint32_t pkts_matched = count_1bits(found_map);
+ lookups_match += pkts_matched * subtable_pos;
- CMAP_NODE_FOR_EACH (rule, cmap_node, nodes[i]) {
- if (OVS_LIKELY(dpcls_rule_matches_key(rule, keys[i]))) {
- rules[i] = rule;
- /* Even at 20 Mpps the 32-bit hit_cnt cannot wrap
- * within one second optimization interval. */
- subtable->hit_cnt++;
- lookups_match += subtable_pos;
- goto next;
- }
- }
- /* None of the found rules was a match. Reset the i-th bit to
- * keep searching this key in the next subtable. */
- ULLONG_SET0(found_map, i); /* Did not match. */
- next:
- ; /* Keep Sparse happy. */
- }
- keys_map &= ~found_map; /* Clear the found rules. */
+ /* Clear the found rules, and return early if all packets are found. */
+ keys_map &= ~found_map;
if (!keys_map) {
if (num_lookups_p) {
*num_lookups_p = lookups_match;
}
- return true; /* All found. */
+ return true;
}
subtable_pos++;
}
+
if (num_lookups_p) {
*num_lookups_p = lookups_match;
}
- return false; /* Some misses. */
+ return false;
}