NAME

       rte_table_hash.h

SYNOPSIS

       #include <stdint.h>
       #include 'rte_table.h'

   Data Structures
       struct rte_table_hash_params

   Typedefs
       typedef uint64_t(* rte_table_hash_op_hash) (void *key, void *key_mask, uint32_t key_size, uint64_t seed)

   Variables
       struct rte_table_ops rte_table_hash_ext_ops
       struct rte_table_ops rte_table_hash_lru_ops

Detailed Description

       RTE Table Hash

       These tables use the exact match criterion to uniquely associate data to lookup keys.

       Hash table types:

       1.  Entry  add  strategy  on  bucket  full: a. Least Recently Used (LRU): One of the existing keys in the
           bucket is deleted and the new key is added in its place. The number of  keys  in  each  bucket  never
           grows  bigger  than 4. The logic to pick the key to be dropped from the bucket is LRU. The hash table
           lookup operation maintains the order in which the keys in the same bucket are hit, so  every  time  a
           key  is  hit,  it  becomes the new Most Recently Used (MRU) key, i.e. the most unlikely candidate for
           drop. When a key is added to the bucket, it also becomes the new MRU key. When  a  key  needs  to  be
           picked  and  dropped, the most likely candidate for drop, i.e. the current LRU key, is always picked.
           The LRU logic requires maintaining specific data structures per each bucket. Use-cases:  flow  cache,
           etc.  b.  Extendable bucket (ext): The bucket is extended with space for 4 more keys. This is done by
           allocating additional memory at table init time, which is used to create a pool  of  free  keys  (the
           size  of  this pool is configurable and always a multiple of 4). On key add operation, the allocation
           of a group of 4 keys only happens successfully within the limit of free keys, otherwise the  key  add
           operation  fails.  On  key delete operation, a group of 4 keys is freed back to the pool of free keys
           when the key to be deleted is the only key that was used within its group of 4 keys at that time.  On
           key  lookup  operation,  if  the  current bucket is in extended state and a match is not found in the
           first group of 4 keys, the search continues beyond the first group of 4 keys, potentially  until  all
           keys  in  this  bucket  are  examined. The extendable bucket logic requires maintaining specific data
           structures per table and per each bucket. Use-cases: flow table, etc.

       2.  Key size: a. Configurable key size b. Single key size (8-byte, 16-byte or 32-byte key size)

       Definition in file rte_table_hash.h.

Typedef Documentation

   typedef uint64_t(* rte_table_hash_op_hash) (void *key, void *key_mask, uint32_t key_size, uint64_t seed)
       Hash function

       Definition at line 56 of file rte_table_hash.h.

Variable Documentation

   struct rte_table_ops rte_table_hash_ext_ops [extern]
       Extendable bucket hash table operations

   struct rte_table_ops rte_table_hash_lru_ops [extern]
       LRU hash table operations

Author

       Generated automatically by Doxygen for DPDK from the source code.

DPDK                                             Version 24.11.2                             rte_table_hash.h(3)