numam-dpdk/lib/efd/rte_efd.h
Stephen Hemminger 448e01f1b5 lib: document free functions
Make sure all functions which use the convention that XXX_free(NULL)
is a nop are all documented.

The wording is chosen to match the documentation of free(3).
"If ptr is NULL, no operation is performed."

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Chengwen Feng <fengchengwen@huawei.com>
[David: squashed with other series updates, unified wording]
2022-06-24 14:50:34 +02:00

281 lines
8.9 KiB
C

/* SPDX-License-Identifier: BSD-3-Clause
* Copyright(c) 2016-2017 Intel Corporation
*/
#ifndef _RTE_EFD_H_
#define _RTE_EFD_H_
/**
* @file
*
* RTE EFD Table
*/
#include <stdint.h>
#ifdef __cplusplus
extern "C" {
#endif
/*************************************************************************
* User selectable constants
*************************************************************************/
/*
* If possible, best lookup performance will be achieved by ensuring that
* the entire table fits in the L3 cache.
*
* Some formulas for calculating various sizes are listed below:
*
* # of chunks =
* 2 ^ (ceiling(log2((requested # of rules) /
* (EFD_CHUNK_NUM_GROUPS * EFD_TARGET_GROUP_NUM_RULES))))
*
* Target # of rules = (# of chunks) * EFD_CHUNK_NUM_GROUPS *
* EFD_TARGET_GROUP_NUM_RULES
*
* Group Size (in bytes) = 4 (per value bit)
*
* Table size (in bytes) = RTE_EFD_VALUE_NUM_BITS * (# of chunks) *
* EFD_CHUNK_NUM_GROUPS * (group size)
*/
/**
* !!! This parameter should be adjusted for your application !!!
*
* This parameter adjusts the number of bits of value that can be
* stored in the table.
* For example, setting the number of bits to 3 will allow storing 8 values
* in the table (between 0 and 7).
*
* This number directly affects the performance of both lookups and insertion.
* In general, performance decreases as more bits are stored in the table.
*
* This number is directly proportional to the size of the online region
* used for lookups.
*
* Note that due to the way the CPU operates on memory, best lookup performance
* will be achieved when RTE_EFD_VALUE_NUM_BITS is a multiple of 8.
* These values align the hash indexes on 16-byte boundaries.
* The greatest performance drop is moving from 8->9 bits, 16->17 bits, etc.
*
* This value must be between 1 and 32
*/
#ifndef RTE_EFD_VALUE_NUM_BITS
#define RTE_EFD_VALUE_NUM_BITS (8)
#endif
/*
* EFD_TARGET_GROUP_NUM_RULES:
* Adjusts how many groups/chunks are allocated at table creation time
* to support the requested number of rules. Higher values pack entries
* more tightly in memory, resulting in a smaller memory footprint
* for the online table.
* This comes at the cost of lower insert/update performance.
*
* EFD_MAX_GROUP_NUM_RULES:
* This adjusts the amount of offline memory allocated to store key/value
* pairs for the table. The recommended numbers are upper-bounds for
* this parameter
* - any higher and it becomes very unlikely that a perfect hash function
* can be found for that group size. This value should be at
* least 40% larger than EFD_TARGET_GROUP_NUM_RULES
*
* Recommended values for various lookuptable and hashfunc sizes are:
*
* HASH_FUNC_SIZE = 16, LOOKUPTBL_SIZE = 16:
* EFD_TARGET_GROUP_NUM_RULES = 22
* EFD_MAX_GROUP_NUM_RULES = 28
*/
#define EFD_TARGET_GROUP_NUM_RULES (22)
#define EFD_MAX_GROUP_NUM_RULES (28LU)
#define EFD_MIN_BALANCED_NUM_RULES 5
/**
* Maximum number of keys that can be looked up in one call to efd_lookup_bulk
*/
#ifndef RTE_EFD_BURST_MAX
#define RTE_EFD_BURST_MAX (32)
#endif
/** Maximum number of characters in efd name.*/
#define RTE_EFD_NAMESIZE 32
#if (RTE_EFD_VALUE_NUM_BITS > 0 && RTE_EFD_VALUE_NUM_BITS <= 8)
typedef uint8_t efd_value_t;
#elif (RTE_EFD_VALUE_NUM_BITS > 8 && RTE_EFD_VALUE_NUM_BITS <= 16)
typedef uint16_t efd_value_t;
#elif (RTE_EFD_VALUE_NUM_BITS > 16 && RTE_EFD_VALUE_NUM_BITS <= 32)
typedef uint32_t efd_value_t;
#else
#error("RTE_EFD_VALUE_NUM_BITS must be in the range [1:32]")
#endif
#define EFD_LOOKUPTBL_SHIFT (32 - 4)
typedef uint16_t efd_lookuptbl_t;
typedef uint16_t efd_hashfunc_t;
/**
* Creates an EFD table with a single offline region and multiple per-socket
* internally-managed copies of the online table used for lookups
*
* @param name
* EFD table name
* @param max_num_rules
* Minimum number of rules the table should be sized to hold.
* Will be rounded up to the next smallest valid table size
* @param key_len
* Length of the key
* @param online_cpu_socket_bitmask
* Bitmask specifying which sockets should get a copy of the online table.
* LSB = socket 0, etc.
* @param offline_cpu_socket
* Identifies the socket where the offline table will be allocated
* (and most efficiently accessed in the case of updates/insertions)
*
* @return
* EFD table, or NULL if table allocation failed or the bitmask is invalid
*/
struct rte_efd_table *
rte_efd_create(const char *name, uint32_t max_num_rules, uint32_t key_len,
uint64_t online_cpu_socket_bitmask, uint8_t offline_cpu_socket);
/**
* Releases the resources from an EFD table
*
* @param table
* Pointer to table allocated with rte_efd_create().
* If table is NULL, no operation is performed.
*/
void
rte_efd_free(struct rte_efd_table *table);
/**
* Find an existing EFD table object and return a pointer to it.
*
* @param name
* Name of the EFD table as passed to rte_efd_create()
* @return
* Pointer to EFD table or NULL if object not found
* with rte_errno set appropriately. Possible rte_errno values include:
* - ENOENT - value not available for return
*/
struct rte_efd_table*
rte_efd_find_existing(const char *name);
#define RTE_EFD_UPDATE_WARN_GROUP_FULL (1)
#define RTE_EFD_UPDATE_NO_CHANGE (2)
#define RTE_EFD_UPDATE_FAILED (3)
/**
* Computes an updated table entry for the supplied key/value pair.
* The update is then immediately applied to the provided table and
* all socket-local copies of the chunks are updated.
* This operation is not multi-thread safe
* and should only be called one from thread.
*
* @param table
* EFD table to reference
* @param socket_id
* Socket ID to use to lookup existing value (ideally caller's socket id)
* @param key
* EFD table key to modify
* @param value
* Value to associate with the key
*
* @return
* RTE_EFD_UPDATE_WARN_GROUP_FULL
* Operation is insert, and the last available space in the
* key's group was just used
* Future inserts may fail as groups fill up
* This operation was still successful, and entry contains a valid update
* RTE_EFD_UPDATE_FAILED
* Either the EFD failed to find a suitable perfect hash or the group was full
* This is a fatal error, and the table is now in an indeterminate state
* RTE_EFD_UPDATE_NO_CHANGE
* Operation resulted in no change to the table (same value already exists)
* 0 - success
*/
int
rte_efd_update(struct rte_efd_table *table, unsigned int socket_id,
const void *key, efd_value_t value);
/**
* Removes any value currently associated with the specified key from the table
* This operation is not multi-thread safe
* and should only be called from one thread.
*
* @param table
* EFD table to reference
* @param socket_id
* Socket ID to use to lookup existing value (ideally caller's socket id)
* @param key
* EFD table key to delete
* @param prev_value
* If not NULL, will store the previous value here before deleting it
*
* @return
* 0 - successfully found and deleted the key
* nonzero otherwise
*/
int
rte_efd_delete(struct rte_efd_table *table, unsigned int socket_id,
const void *key, efd_value_t *prev_value);
/**
* Looks up the value associated with a key
* This operation is multi-thread safe.
*
* NOTE: Lookups will *always* succeed - this is a property of
* using a perfect hash table.
* If the specified key was never inserted, a pseudorandom answer will be returned.
* There is no way to know based on the lookup if the key was ever inserted
* originally, so this must be tracked elsewhere.
*
* @param table
* EFD table to reference
* @param socket_id
* Socket ID to use to lookup existing value (ideally caller's socket id)
* @param key
* EFD table key to look up
*
* @return
* Value associated with the key, or random junk if they key was never inserted
*/
efd_value_t
rte_efd_lookup(const struct rte_efd_table *table, unsigned int socket_id,
const void *key);
/**
* Looks up the value associated with several keys.
* This operation is multi-thread safe.
*
* NOTE: Lookups will *always* succeed - this is a property of
* using a perfect hash table.
* If the specified key was never inserted, a pseudorandom answer will be returned.
* There is no way to know based on the lookup if the key was ever inserted
* originally, so this must be tracked elsewhere.
*
* @param table
* EFD table to reference
* @param socket_id
* Socket ID to use to lookup existing value (ideally caller's socket id)
* @param num_keys
* Number of keys in the key_list array, must be less than RTE_EFD_BURST_MAX
* @param key_list
* Array of num_keys pointers which point to keys to look up
* @param value_list
* Array of size num_keys where lookup values will be stored
*/
void
rte_efd_lookup_bulk(const struct rte_efd_table *table, unsigned int socket_id,
int num_keys, const void **key_list,
efd_value_t *value_list);
#ifdef __cplusplus
}
#endif
#endif /* _RTE_EFD_H_ */