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34 #ifndef __INCLUDE_RTE_TABLE_HASH_H__
35 #define __INCLUDE_RTE_TABLE_HASH_H__
45 * These tables use the exact match criterion to uniquely associate data to
48 * Use-cases: Flow classification table, Address Resolution Protocol (ARP) table
51 * 1. Entry add strategy on bucket full:
52 * a. Least Recently Used (LRU): One of the existing keys in the bucket is
53 * deleted and the new key is added in its place. The number of keys in
54 * each bucket never grows bigger than 4. The logic to pick the key to
55 * be dropped from the bucket is LRU. The hash table lookup operation
56 * maintains the order in which the keys in the same bucket are hit, so
57 * every time a key is hit, it becomes the new Most Recently Used (MRU)
58 * key, i.e. the most unlikely candidate for drop. When a key is added
59 * to the bucket, it also becomes the new MRU key. When a key needs to
60 * be picked and dropped, the most likely candidate for drop, i.e. the
61 * current LRU key, is always picked. The LRU logic requires maintaining
62 * specific data structures per each bucket.
63 * b. Extendible bucket (ext): The bucket is extended with space for 4 more
64 * keys. This is done by allocating additional memory at table init time,
65 * which is used to create a pool of free keys (the size of this pool is
66 * configurable and always a multiple of 4). On key add operation, the
67 * allocation of a group of 4 keys only happens successfully within the
68 * limit of free keys, otherwise the key add operation fails. On key
69 * delete operation, a group of 4 keys is freed back to the pool of free
70 * keys when the key to be deleted is the only key that was used within
71 * its group of 4 keys at that time. On key lookup operation, if the
72 * current bucket is in extended state and a match is not found in the
73 * first group of 4 keys, the search continues beyond the first group of
74 * 4 keys, potentially until all keys in this bucket are examined. The
75 * extendible bucket logic requires maintaining specific data structures
76 * per table and per each bucket.
77 * 2. Key signature computation:
78 * a. Pre-computed key signature: The key lookup operation is split between
79 * two CPU cores. The first CPU core (typically the CPU core performing
80 * packet RX) extracts the key from the input packet, computes the key
81 * signature and saves both the key and the key signature in the packet
82 * buffer as packet meta-data. The second CPU core reads both the key and
83 * the key signature from the packet meta-data and performs the bucket
84 * search step of the key lookup operation.
85 * b. Key signature computed on lookup (do-sig): The same CPU core reads
86 * the key from the packet meta-data, uses it to compute the key
87 * signature and also performs the bucket search step of the key lookup
90 * a. Configurable key size
91 * b. Single key size (8-byte, 16-byte or 32-byte key size)
96 #include "rte_table.h"
99 typedef uint64_t (*rte_table_hash_op_hash)(
105 * Hash tables with configurable key size
108 /** Extendible bucket hash table parameters */
109 struct rte_table_hash_ext_params {
110 /** Key size (number of bytes) */
113 /** Maximum number of keys */
116 /** Number of hash table buckets. Each bucket stores up to 4 keys. */
119 /** Number of hash table bucket extensions. Each bucket extension has
120 space for 4 keys and each bucket can have 0, 1 or more extensions. */
121 uint32_t n_buckets_ext;
124 rte_table_hash_op_hash f_hash;
126 /** Seed value for the hash function */
129 /** Byte offset within packet meta-data where the 4-byte key signature
130 is located. Valid for pre-computed key signature tables, ignored for
132 uint32_t signature_offset;
134 /** Byte offset within packet meta-data where the key is located */
138 extern struct rte_table_ops rte_table_hash_ext_ops;
140 /** LRU hash table parameters */
141 struct rte_table_hash_lru_params {
142 /** Key size (number of bytes) */
145 /** Maximum number of keys */
148 /** Number of hash table buckets. Each bucket stores up to 4 keys. */
152 rte_table_hash_op_hash f_hash;
154 /** Seed value for the hash function */
157 /** Byte offset within packet meta-data where the 4-byte key signature
158 is located. Valid for pre-computed key signature tables, ignored for
160 uint32_t signature_offset;
162 /** Byte offset within packet meta-data where the key is located */
166 /** LRU hash table operations for pre-computed key signature */
167 extern struct rte_table_ops rte_table_hash_lru_ops;
169 /** LRU hash table operations for key signature computed on lookup ("do-sig") */
170 extern struct rte_table_ops rte_table_hash_lru_dosig_ops;
173 * 8-byte key hash tables
176 /** LRU hash table parameters */
177 struct rte_table_hash_key8_lru_params {
178 /** Maximum number of entries (and keys) in the table */
182 rte_table_hash_op_hash f_hash;
184 /** Seed for the hash function */
187 /** Byte offset within packet meta-data where the 4-byte key signature
188 is located. Valid for pre-computed key signature tables, ignored for
190 uint32_t signature_offset;
192 /** Byte offset within packet meta-data where the key is located */
195 /** Bit-mask to be AND-ed to the key on lookup */
199 extern struct rte_table_ops rte_table_hash_key8_lru_ops;
201 /** Extendible bucket hash table parameters */
202 struct rte_table_hash_key8_ext_params {
203 /** Maximum number of entries (and keys) in the table */
206 /** Number of entries (and keys) for hash table bucket extensions. Each
207 bucket is extended in increments of 4 keys. */
208 uint32_t n_entries_ext;
211 rte_table_hash_op_hash f_hash;
213 /** Seed for the hash function */
216 /** Byte offset within packet meta-data where the 4-byte key signature
217 is located. Valid for pre-computed key signature tables, ignored for
219 uint32_t signature_offset;
221 /** Byte offset within packet meta-data where the key is located */
224 /** Bit-mask to be AND-ed to the key on lookup */
228 extern struct rte_table_ops rte_table_hash_key8_ext_ops;
231 * 16-byte key hash tables
234 /** LRU hash table parameters */
235 struct rte_table_hash_key16_lru_params {
236 /** Maximum number of entries (and keys) in the table */
240 rte_table_hash_op_hash f_hash;
242 /** Seed for the hash function */
245 /** Byte offset within packet meta-data where the 4-byte key signature
246 is located. Valid for pre-computed key signature tables, ignored for
248 uint32_t signature_offset;
250 /** Byte offset within packet meta-data where the key is located */
253 /** Bit-mask to be AND-ed to the key on lookup */
257 extern struct rte_table_ops rte_table_hash_key16_lru_ops;
259 /** Extendible bucket hash table parameters */
260 struct rte_table_hash_key16_ext_params {
261 /** Maximum number of entries (and keys) in the table */
264 /** Number of entries (and keys) for hash table bucket extensions. Each
265 bucket is extended in increments of 4 keys. */
266 uint32_t n_entries_ext;
269 rte_table_hash_op_hash f_hash;
271 /** Seed for the hash function */
274 /** Byte offset within packet meta-data where the 4-byte key signature
275 is located. Valid for pre-computed key signature tables, ignored for
277 uint32_t signature_offset;
279 /** Byte offset within packet meta-data where the key is located */
282 /** Bit-mask to be AND-ed to the key on lookup */
286 extern struct rte_table_ops rte_table_hash_key16_ext_ops;
289 * 32-byte key hash tables
292 /** LRU hash table parameters */
293 struct rte_table_hash_key32_lru_params {
294 /** Maximum number of entries (and keys) in the table */
298 rte_table_hash_op_hash f_hash;
300 /** Seed for the hash function */
303 /** Byte offset within packet meta-data where the 4-byte key signature
304 is located. Valid for pre-computed key signature tables, ignored for
306 uint32_t signature_offset;
308 /** Byte offset within packet meta-data where the key is located */
312 /** LRU hash table operations for pre-computed key signature */
313 extern struct rte_table_ops rte_table_hash_key32_lru_ops;
315 /** Extendible bucket hash table parameters */
316 struct rte_table_hash_key32_ext_params {
317 /** Maximum number of entries (and keys) in the table */
320 /** Number of entries (and keys) for hash table bucket extensions. Each
321 bucket is extended in increments of 4 keys. */
322 uint32_t n_entries_ext;
325 rte_table_hash_op_hash f_hash;
327 /** Seed for the hash function */
330 /** Byte offset within packet meta-data where the 4-byte key signature
331 is located. Valid for pre-computed key signature tables, ignored for
333 uint32_t signature_offset;
335 /** Byte offset within packet meta-data where the key is located */
339 /** Extendible bucket hash table operations */
340 extern struct rte_table_ops rte_table_hash_key32_ext_ops;
342 /** Cuckoo hash table parameters */
343 struct rte_table_hash_cuckoo_params {
344 /** Key size (number of bytes */
347 /** Maximum number of hash table entries */
350 /** Hash function used to calculate hash */
351 rte_table_hash_op_hash f_hash;
353 /** Seed value or Init value used by f_hash */
356 /** Byte offset within packet meta-data where the 4-byte key signature
357 is located. Valid for pre-computed key signature tables, ignored for
359 uint32_t signature_offset;
361 /** Byte offset within packet meta-data where the key is located */
364 /** Hash table name */
368 /** Cuckoo hash table operations */
369 extern struct rte_table_ops rte_table_hash_cuckoo_dosig_ops;