numam-dpdk/lib/librte_ring/rte_ring.h
Morten Brørup 4b7284a71f ring: optimize empty test
Testing if the ring is empty is as simple as comparing the producer and
consumer pointers.

In theory, this optimization reduces the number of potential cache misses
from 3 to 2 by not having to read r->mask in rte_ring_count().

The modification of this function were also discussed in the RFC here:
https://mails.dpdk.org/archives/dev/2020-April/165752.html

Signed-off-by: Morten Brørup <mb@smartsharesystems.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
2020-07-01 11:46:09 +02:00

1040 lines
31 KiB
C

/* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 2010-2020 Intel Corporation
* Copyright (c) 2007-2009 Kip Macy kmacy@freebsd.org
* All rights reserved.
* Derived from FreeBSD's bufring.h
* Used as BSD-3 Licensed with permission from Kip Macy.
*/
#ifndef _RTE_RING_H_
#define _RTE_RING_H_
/**
* @file
* RTE Ring
*
* The Ring Manager is a fixed-size queue, implemented as a table of
* pointers. Head and tail pointers are modified atomically, allowing
* concurrent access to it. It has the following features:
*
* - FIFO (First In First Out)
* - Maximum size is fixed; the pointers are stored in a table.
* - Lockless implementation.
* - Multi- or single-consumer dequeue.
* - Multi- or single-producer enqueue.
* - Bulk dequeue.
* - Bulk enqueue.
* - Ability to select different sync modes for producer/consumer.
* - Dequeue start/finish (depending on consumer sync modes).
* - Enqueue start/finish (depending on producer sync mode).
*
* Note: the ring implementation is not preemptible. Refer to Programmer's
* guide/Environment Abstraction Layer/Multiple pthread/Known Issues/rte_ring
* for more information.
*
*/
#ifdef __cplusplus
extern "C" {
#endif
#include <rte_ring_core.h>
/**
* Calculate the memory size needed for a ring
*
* This function returns the number of bytes needed for a ring, given
* the number of elements in it. This value is the sum of the size of
* the structure rte_ring and the size of the memory needed by the
* objects pointers. The value is aligned to a cache line size.
*
* @param count
* The number of elements in the ring (must be a power of 2).
* @return
* - The memory size needed for the ring on success.
* - -EINVAL if count is not a power of 2.
*/
ssize_t rte_ring_get_memsize(unsigned int count);
/**
* Initialize a ring structure.
*
* Initialize a ring structure in memory pointed by "r". The size of the
* memory area must be large enough to store the ring structure and the
* object table. It is advised to use rte_ring_get_memsize() to get the
* appropriate size.
*
* The ring size is set to *count*, which must be a power of two. Water
* marking is disabled by default. The real usable ring size is
* *count-1* instead of *count* to differentiate a free ring from an
* empty ring.
*
* The ring is not added in RTE_TAILQ_RING global list. Indeed, the
* memory given by the caller may not be shareable among dpdk
* processes.
*
* @param r
* The pointer to the ring structure followed by the objects table.
* @param name
* The name of the ring.
* @param count
* The number of elements in the ring (must be a power of 2).
* @param flags
* An OR of the following:
* - One of mutually exclusive flags that define producer behavior:
* - RING_F_SP_ENQ: If this flag is set, the default behavior when
* using ``rte_ring_enqueue()`` or ``rte_ring_enqueue_bulk()``
* is "single-producer".
* - RING_F_MP_RTS_ENQ: If this flag is set, the default behavior when
* using ``rte_ring_enqueue()`` or ``rte_ring_enqueue_bulk()``
* is "multi-producer RTS mode".
* - RING_F_MP_HTS_ENQ: If this flag is set, the default behavior when
* using ``rte_ring_enqueue()`` or ``rte_ring_enqueue_bulk()``
* is "multi-producer HTS mode".
* If none of these flags is set, then default "multi-producer"
* behavior is selected.
* - One of mutually exclusive flags that define consumer behavior:
* - RING_F_SC_DEQ: If this flag is set, the default behavior when
* using ``rte_ring_dequeue()`` or ``rte_ring_dequeue_bulk()``
* is "single-consumer". Otherwise, it is "multi-consumers".
* - RING_F_MC_RTS_DEQ: If this flag is set, the default behavior when
* using ``rte_ring_dequeue()`` or ``rte_ring_dequeue_bulk()``
* is "multi-consumer RTS mode".
* - RING_F_MC_HTS_DEQ: If this flag is set, the default behavior when
* using ``rte_ring_dequeue()`` or ``rte_ring_dequeue_bulk()``
* is "multi-consumer HTS mode".
* If none of these flags is set, then default "multi-consumer"
* behavior is selected.
* @return
* 0 on success, or a negative value on error.
*/
int rte_ring_init(struct rte_ring *r, const char *name, unsigned int count,
unsigned int flags);
/**
* Create a new ring named *name* in memory.
*
* This function uses ``memzone_reserve()`` to allocate memory. Then it
* calls rte_ring_init() to initialize an empty ring.
*
* The new ring size is set to *count*, which must be a power of
* two. Water marking is disabled by default. The real usable ring size
* is *count-1* instead of *count* to differentiate a free ring from an
* empty ring.
*
* The ring is added in RTE_TAILQ_RING list.
*
* @param name
* The name of the ring.
* @param count
* The size of the ring (must be a power of 2).
* @param socket_id
* The *socket_id* argument is the socket identifier in case of
* NUMA. The value can be *SOCKET_ID_ANY* if there is no NUMA
* constraint for the reserved zone.
* @param flags
* An OR of the following:
* - One of mutually exclusive flags that define producer behavior:
* - RING_F_SP_ENQ: If this flag is set, the default behavior when
* using ``rte_ring_enqueue()`` or ``rte_ring_enqueue_bulk()``
* is "single-producer".
* - RING_F_MP_RTS_ENQ: If this flag is set, the default behavior when
* using ``rte_ring_enqueue()`` or ``rte_ring_enqueue_bulk()``
* is "multi-producer RTS mode".
* - RING_F_MP_HTS_ENQ: If this flag is set, the default behavior when
* using ``rte_ring_enqueue()`` or ``rte_ring_enqueue_bulk()``
* is "multi-producer HTS mode".
* If none of these flags is set, then default "multi-producer"
* behavior is selected.
* - One of mutually exclusive flags that define consumer behavior:
* - RING_F_SC_DEQ: If this flag is set, the default behavior when
* using ``rte_ring_dequeue()`` or ``rte_ring_dequeue_bulk()``
* is "single-consumer". Otherwise, it is "multi-consumers".
* - RING_F_MC_RTS_DEQ: If this flag is set, the default behavior when
* using ``rte_ring_dequeue()`` or ``rte_ring_dequeue_bulk()``
* is "multi-consumer RTS mode".
* - RING_F_MC_HTS_DEQ: If this flag is set, the default behavior when
* using ``rte_ring_dequeue()`` or ``rte_ring_dequeue_bulk()``
* is "multi-consumer HTS mode".
* If none of these flags is set, then default "multi-consumer"
* behavior is selected.
* @return
* On success, the pointer to the new allocated ring. NULL on error with
* rte_errno set appropriately. Possible errno values include:
* - E_RTE_NO_CONFIG - function could not get pointer to rte_config structure
* - E_RTE_SECONDARY - function was called from a secondary process instance
* - EINVAL - count provided is not a power of 2
* - ENOSPC - the maximum number of memzones has already been allocated
* - EEXIST - a memzone with the same name already exists
* - ENOMEM - no appropriate memory area found in which to create memzone
*/
struct rte_ring *rte_ring_create(const char *name, unsigned int count,
int socket_id, unsigned int flags);
/**
* De-allocate all memory used by the ring.
*
* @param r
* Ring to free
*/
void rte_ring_free(struct rte_ring *r);
/**
* Dump the status of the ring to a file.
*
* @param f
* A pointer to a file for output
* @param r
* A pointer to the ring structure.
*/
void rte_ring_dump(FILE *f, const struct rte_ring *r);
/* the actual enqueue of pointers on the ring.
* Placed here since identical code needed in both
* single and multi producer enqueue functions */
#define ENQUEUE_PTRS(r, ring_start, prod_head, obj_table, n, obj_type) do { \
unsigned int i; \
const uint32_t size = (r)->size; \
uint32_t idx = prod_head & (r)->mask; \
obj_type *ring = (obj_type *)ring_start; \
if (likely(idx + n < size)) { \
for (i = 0; i < (n & ~0x3); i += 4, idx += 4) { \
ring[idx] = obj_table[i]; \
ring[idx + 1] = obj_table[i + 1]; \
ring[idx + 2] = obj_table[i + 2]; \
ring[idx + 3] = obj_table[i + 3]; \
} \
switch (n & 0x3) { \
case 3: \
ring[idx++] = obj_table[i++]; /* fallthrough */ \
case 2: \
ring[idx++] = obj_table[i++]; /* fallthrough */ \
case 1: \
ring[idx++] = obj_table[i++]; \
} \
} else { \
for (i = 0; idx < size; i++, idx++)\
ring[idx] = obj_table[i]; \
for (idx = 0; i < n; i++, idx++) \
ring[idx] = obj_table[i]; \
} \
} while (0)
/* the actual copy of pointers on the ring to obj_table.
* Placed here since identical code needed in both
* single and multi consumer dequeue functions */
#define DEQUEUE_PTRS(r, ring_start, cons_head, obj_table, n, obj_type) do { \
unsigned int i; \
uint32_t idx = cons_head & (r)->mask; \
const uint32_t size = (r)->size; \
obj_type *ring = (obj_type *)ring_start; \
if (likely(idx + n < size)) { \
for (i = 0; i < (n & ~0x3); i += 4, idx += 4) {\
obj_table[i] = ring[idx]; \
obj_table[i + 1] = ring[idx + 1]; \
obj_table[i + 2] = ring[idx + 2]; \
obj_table[i + 3] = ring[idx + 3]; \
} \
switch (n & 0x3) { \
case 3: \
obj_table[i++] = ring[idx++]; /* fallthrough */ \
case 2: \
obj_table[i++] = ring[idx++]; /* fallthrough */ \
case 1: \
obj_table[i++] = ring[idx++]; \
} \
} else { \
for (i = 0; idx < size; i++, idx++) \
obj_table[i] = ring[idx]; \
for (idx = 0; i < n; i++, idx++) \
obj_table[i] = ring[idx]; \
} \
} while (0)
/* Between load and load. there might be cpu reorder in weak model
* (powerpc/arm).
* There are 2 choices for the users
* 1.use rmb() memory barrier
* 2.use one-direction load_acquire/store_release barrier,defined by
* CONFIG_RTE_USE_C11_MEM_MODEL=y
* It depends on performance test results.
* By default, move common functions to rte_ring_generic.h
*/
#ifdef RTE_USE_C11_MEM_MODEL
#include "rte_ring_c11_mem.h"
#else
#include "rte_ring_generic.h"
#endif
/**
* @internal Enqueue several objects on the ring
*
* @param r
* A pointer to the ring structure.
* @param obj_table
* A pointer to a table of void * pointers (objects).
* @param n
* The number of objects to add in the ring from the obj_table.
* @param behavior
* RTE_RING_QUEUE_FIXED: Enqueue a fixed number of items from a ring
* RTE_RING_QUEUE_VARIABLE: Enqueue as many items as possible from ring
* @param is_sp
* Indicates whether to use single producer or multi-producer head update
* @param free_space
* returns the amount of space after the enqueue operation has finished
* @return
* Actual number of objects enqueued.
* If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
*/
static __rte_always_inline unsigned int
__rte_ring_do_enqueue(struct rte_ring *r, void * const *obj_table,
unsigned int n, enum rte_ring_queue_behavior behavior,
unsigned int is_sp, unsigned int *free_space)
{
uint32_t prod_head, prod_next;
uint32_t free_entries;
n = __rte_ring_move_prod_head(r, is_sp, n, behavior,
&prod_head, &prod_next, &free_entries);
if (n == 0)
goto end;
ENQUEUE_PTRS(r, &r[1], prod_head, obj_table, n, void *);
update_tail(&r->prod, prod_head, prod_next, is_sp, 1);
end:
if (free_space != NULL)
*free_space = free_entries - n;
return n;
}
/**
* @internal Dequeue several objects from the ring
*
* @param r
* A pointer to the ring structure.
* @param obj_table
* A pointer to a table of void * pointers (objects).
* @param n
* The number of objects to pull from the ring.
* @param behavior
* RTE_RING_QUEUE_FIXED: Dequeue a fixed number of items from a ring
* RTE_RING_QUEUE_VARIABLE: Dequeue as many items as possible from ring
* @param is_sc
* Indicates whether to use single consumer or multi-consumer head update
* @param available
* returns the number of remaining ring entries after the dequeue has finished
* @return
* - Actual number of objects dequeued.
* If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
*/
static __rte_always_inline unsigned int
__rte_ring_do_dequeue(struct rte_ring *r, void **obj_table,
unsigned int n, enum rte_ring_queue_behavior behavior,
unsigned int is_sc, unsigned int *available)
{
uint32_t cons_head, cons_next;
uint32_t entries;
n = __rte_ring_move_cons_head(r, (int)is_sc, n, behavior,
&cons_head, &cons_next, &entries);
if (n == 0)
goto end;
DEQUEUE_PTRS(r, &r[1], cons_head, obj_table, n, void *);
update_tail(&r->cons, cons_head, cons_next, is_sc, 0);
end:
if (available != NULL)
*available = entries - n;
return n;
}
/**
* Enqueue several objects on the ring (multi-producers safe).
*
* This function uses a "compare and set" instruction to move the
* producer index atomically.
*
* @param r
* A pointer to the ring structure.
* @param obj_table
* A pointer to a table of void * pointers (objects).
* @param n
* The number of objects to add in the ring from the obj_table.
* @param free_space
* if non-NULL, returns the amount of space in the ring after the
* enqueue operation has finished.
* @return
* The number of objects enqueued, either 0 or n
*/
static __rte_always_inline unsigned int
rte_ring_mp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
unsigned int n, unsigned int *free_space)
{
return __rte_ring_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
RTE_RING_SYNC_MT, free_space);
}
/**
* Enqueue several objects on a ring (NOT multi-producers safe).
*
* @param r
* A pointer to the ring structure.
* @param obj_table
* A pointer to a table of void * pointers (objects).
* @param n
* The number of objects to add in the ring from the obj_table.
* @param free_space
* if non-NULL, returns the amount of space in the ring after the
* enqueue operation has finished.
* @return
* The number of objects enqueued, either 0 or n
*/
static __rte_always_inline unsigned int
rte_ring_sp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
unsigned int n, unsigned int *free_space)
{
return __rte_ring_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
RTE_RING_SYNC_ST, free_space);
}
#ifdef ALLOW_EXPERIMENTAL_API
#include <rte_ring_elem.h>
#endif
/**
* Enqueue several objects on a ring.
*
* This function calls the multi-producer or the single-producer
* version depending on the default behavior that was specified at
* ring creation time (see flags).
*
* @param r
* A pointer to the ring structure.
* @param obj_table
* A pointer to a table of void * pointers (objects).
* @param n
* The number of objects to add in the ring from the obj_table.
* @param free_space
* if non-NULL, returns the amount of space in the ring after the
* enqueue operation has finished.
* @return
* The number of objects enqueued, either 0 or n
*/
static __rte_always_inline unsigned int
rte_ring_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
unsigned int n, unsigned int *free_space)
{
switch (r->prod.sync_type) {
case RTE_RING_SYNC_MT:
return rte_ring_mp_enqueue_bulk(r, obj_table, n, free_space);
case RTE_RING_SYNC_ST:
return rte_ring_sp_enqueue_bulk(r, obj_table, n, free_space);
#ifdef ALLOW_EXPERIMENTAL_API
case RTE_RING_SYNC_MT_RTS:
return rte_ring_mp_rts_enqueue_bulk(r, obj_table, n,
free_space);
case RTE_RING_SYNC_MT_HTS:
return rte_ring_mp_hts_enqueue_bulk(r, obj_table, n,
free_space);
#endif
}
/* valid ring should never reach this point */
RTE_ASSERT(0);
return 0;
}
/**
* Enqueue one object on a ring (multi-producers safe).
*
* This function uses a "compare and set" instruction to move the
* producer index atomically.
*
* @param r
* A pointer to the ring structure.
* @param obj
* A pointer to the object to be added.
* @return
* - 0: Success; objects enqueued.
* - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
*/
static __rte_always_inline int
rte_ring_mp_enqueue(struct rte_ring *r, void *obj)
{
return rte_ring_mp_enqueue_bulk(r, &obj, 1, NULL) ? 0 : -ENOBUFS;
}
/**
* Enqueue one object on a ring (NOT multi-producers safe).
*
* @param r
* A pointer to the ring structure.
* @param obj
* A pointer to the object to be added.
* @return
* - 0: Success; objects enqueued.
* - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
*/
static __rte_always_inline int
rte_ring_sp_enqueue(struct rte_ring *r, void *obj)
{
return rte_ring_sp_enqueue_bulk(r, &obj, 1, NULL) ? 0 : -ENOBUFS;
}
/**
* Enqueue one object on a ring.
*
* This function calls the multi-producer or the single-producer
* version, depending on the default behaviour that was specified at
* ring creation time (see flags).
*
* @param r
* A pointer to the ring structure.
* @param obj
* A pointer to the object to be added.
* @return
* - 0: Success; objects enqueued.
* - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
*/
static __rte_always_inline int
rte_ring_enqueue(struct rte_ring *r, void *obj)
{
return rte_ring_enqueue_bulk(r, &obj, 1, NULL) ? 0 : -ENOBUFS;
}
/**
* Dequeue several objects from a ring (multi-consumers safe).
*
* This function uses a "compare and set" instruction to move the
* consumer index atomically.
*
* @param r
* A pointer to the ring structure.
* @param obj_table
* A pointer to a table of void * pointers (objects) that will be filled.
* @param n
* The number of objects to dequeue from the ring to the obj_table.
* @param available
* If non-NULL, returns the number of remaining ring entries after the
* dequeue has finished.
* @return
* The number of objects dequeued, either 0 or n
*/
static __rte_always_inline unsigned int
rte_ring_mc_dequeue_bulk(struct rte_ring *r, void **obj_table,
unsigned int n, unsigned int *available)
{
return __rte_ring_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
RTE_RING_SYNC_MT, available);
}
/**
* Dequeue several objects from a ring (NOT multi-consumers safe).
*
* @param r
* A pointer to the ring structure.
* @param obj_table
* A pointer to a table of void * pointers (objects) that will be filled.
* @param n
* The number of objects to dequeue from the ring to the obj_table,
* must be strictly positive.
* @param available
* If non-NULL, returns the number of remaining ring entries after the
* dequeue has finished.
* @return
* The number of objects dequeued, either 0 or n
*/
static __rte_always_inline unsigned int
rte_ring_sc_dequeue_bulk(struct rte_ring *r, void **obj_table,
unsigned int n, unsigned int *available)
{
return __rte_ring_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
RTE_RING_SYNC_ST, available);
}
/**
* Dequeue several objects from a ring.
*
* This function calls the multi-consumers or the single-consumer
* version, depending on the default behaviour that was specified at
* ring creation time (see flags).
*
* @param r
* A pointer to the ring structure.
* @param obj_table
* A pointer to a table of void * pointers (objects) that will be filled.
* @param n
* The number of objects to dequeue from the ring to the obj_table.
* @param available
* If non-NULL, returns the number of remaining ring entries after the
* dequeue has finished.
* @return
* The number of objects dequeued, either 0 or n
*/
static __rte_always_inline unsigned int
rte_ring_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned int n,
unsigned int *available)
{
switch (r->cons.sync_type) {
case RTE_RING_SYNC_MT:
return rte_ring_mc_dequeue_bulk(r, obj_table, n, available);
case RTE_RING_SYNC_ST:
return rte_ring_sc_dequeue_bulk(r, obj_table, n, available);
#ifdef ALLOW_EXPERIMENTAL_API
case RTE_RING_SYNC_MT_RTS:
return rte_ring_mc_rts_dequeue_bulk(r, obj_table, n, available);
case RTE_RING_SYNC_MT_HTS:
return rte_ring_mc_hts_dequeue_bulk(r, obj_table, n, available);
#endif
}
/* valid ring should never reach this point */
RTE_ASSERT(0);
return 0;
}
/**
* Dequeue one object from a ring (multi-consumers safe).
*
* This function uses a "compare and set" instruction to move the
* consumer index atomically.
*
* @param r
* A pointer to the ring structure.
* @param obj_p
* A pointer to a void * pointer (object) that will be filled.
* @return
* - 0: Success; objects dequeued.
* - -ENOENT: Not enough entries in the ring to dequeue; no object is
* dequeued.
*/
static __rte_always_inline int
rte_ring_mc_dequeue(struct rte_ring *r, void **obj_p)
{
return rte_ring_mc_dequeue_bulk(r, obj_p, 1, NULL) ? 0 : -ENOENT;
}
/**
* Dequeue one object from a ring (NOT multi-consumers safe).
*
* @param r
* A pointer to the ring structure.
* @param obj_p
* A pointer to a void * pointer (object) that will be filled.
* @return
* - 0: Success; objects dequeued.
* - -ENOENT: Not enough entries in the ring to dequeue, no object is
* dequeued.
*/
static __rte_always_inline int
rte_ring_sc_dequeue(struct rte_ring *r, void **obj_p)
{
return rte_ring_sc_dequeue_bulk(r, obj_p, 1, NULL) ? 0 : -ENOENT;
}
/**
* Dequeue one object from a ring.
*
* This function calls the multi-consumers or the single-consumer
* version depending on the default behaviour that was specified at
* ring creation time (see flags).
*
* @param r
* A pointer to the ring structure.
* @param obj_p
* A pointer to a void * pointer (object) that will be filled.
* @return
* - 0: Success, objects dequeued.
* - -ENOENT: Not enough entries in the ring to dequeue, no object is
* dequeued.
*/
static __rte_always_inline int
rte_ring_dequeue(struct rte_ring *r, void **obj_p)
{
return rte_ring_dequeue_bulk(r, obj_p, 1, NULL) ? 0 : -ENOENT;
}
/**
* Flush a ring.
*
* This function flush all the elements in a ring
*
* @b EXPERIMENTAL: this API may change without prior notice
*
* @warning
* Make sure the ring is not in use while calling this function.
*
* @param r
* A pointer to the ring structure.
*/
__rte_experimental
void
rte_ring_reset(struct rte_ring *r);
/**
* Return the number of entries in a ring.
*
* @param r
* A pointer to the ring structure.
* @return
* The number of entries in the ring.
*/
static inline unsigned int
rte_ring_count(const struct rte_ring *r)
{
uint32_t prod_tail = r->prod.tail;
uint32_t cons_tail = r->cons.tail;
uint32_t count = (prod_tail - cons_tail) & r->mask;
return (count > r->capacity) ? r->capacity : count;
}
/**
* Return the number of free entries in a ring.
*
* @param r
* A pointer to the ring structure.
* @return
* The number of free entries in the ring.
*/
static inline unsigned int
rte_ring_free_count(const struct rte_ring *r)
{
return r->capacity - rte_ring_count(r);
}
/**
* Test if a ring is full.
*
* @param r
* A pointer to the ring structure.
* @return
* - 1: The ring is full.
* - 0: The ring is not full.
*/
static inline int
rte_ring_full(const struct rte_ring *r)
{
return rte_ring_free_count(r) == 0;
}
/**
* Test if a ring is empty.
*
* @param r
* A pointer to the ring structure.
* @return
* - 1: The ring is empty.
* - 0: The ring is not empty.
*/
static inline int
rte_ring_empty(const struct rte_ring *r)
{
uint32_t prod_tail = r->prod.tail;
uint32_t cons_tail = r->cons.tail;
return cons_tail == prod_tail;
}
/**
* Return the size of the ring.
*
* @param r
* A pointer to the ring structure.
* @return
* The size of the data store used by the ring.
* NOTE: this is not the same as the usable space in the ring. To query that
* use ``rte_ring_get_capacity()``.
*/
static inline unsigned int
rte_ring_get_size(const struct rte_ring *r)
{
return r->size;
}
/**
* Return the number of elements which can be stored in the ring.
*
* @param r
* A pointer to the ring structure.
* @return
* The usable size of the ring.
*/
static inline unsigned int
rte_ring_get_capacity(const struct rte_ring *r)
{
return r->capacity;
}
/**
* Return sync type used by producer in the ring.
*
* @param r
* A pointer to the ring structure.
* @return
* Producer sync type value.
*/
static inline enum rte_ring_sync_type
rte_ring_get_prod_sync_type(const struct rte_ring *r)
{
return r->prod.sync_type;
}
/**
* Check is the ring for single producer.
*
* @param r
* A pointer to the ring structure.
* @return
* true if ring is SP, zero otherwise.
*/
static inline int
rte_ring_is_prod_single(const struct rte_ring *r)
{
return (rte_ring_get_prod_sync_type(r) == RTE_RING_SYNC_ST);
}
/**
* Return sync type used by consumer in the ring.
*
* @param r
* A pointer to the ring structure.
* @return
* Consumer sync type value.
*/
static inline enum rte_ring_sync_type
rte_ring_get_cons_sync_type(const struct rte_ring *r)
{
return r->cons.sync_type;
}
/**
* Check is the ring for single consumer.
*
* @param r
* A pointer to the ring structure.
* @return
* true if ring is SC, zero otherwise.
*/
static inline int
rte_ring_is_cons_single(const struct rte_ring *r)
{
return (rte_ring_get_cons_sync_type(r) == RTE_RING_SYNC_ST);
}
/**
* Dump the status of all rings on the console
*
* @param f
* A pointer to a file for output
*/
void rte_ring_list_dump(FILE *f);
/**
* Search a ring from its name
*
* @param name
* The name of the ring.
* @return
* The pointer to the ring matching the name, or NULL if not found,
* with rte_errno set appropriately. Possible rte_errno values include:
* - ENOENT - required entry not available to return.
*/
struct rte_ring *rte_ring_lookup(const char *name);
/**
* Enqueue several objects on the ring (multi-producers safe).
*
* This function uses a "compare and set" instruction to move the
* producer index atomically.
*
* @param r
* A pointer to the ring structure.
* @param obj_table
* A pointer to a table of void * pointers (objects).
* @param n
* The number of objects to add in the ring from the obj_table.
* @param free_space
* if non-NULL, returns the amount of space in the ring after the
* enqueue operation has finished.
* @return
* - n: Actual number of objects enqueued.
*/
static __rte_always_inline unsigned int
rte_ring_mp_enqueue_burst(struct rte_ring *r, void * const *obj_table,
unsigned int n, unsigned int *free_space)
{
return __rte_ring_do_enqueue(r, obj_table, n,
RTE_RING_QUEUE_VARIABLE, RTE_RING_SYNC_MT, free_space);
}
/**
* Enqueue several objects on a ring (NOT multi-producers safe).
*
* @param r
* A pointer to the ring structure.
* @param obj_table
* A pointer to a table of void * pointers (objects).
* @param n
* The number of objects to add in the ring from the obj_table.
* @param free_space
* if non-NULL, returns the amount of space in the ring after the
* enqueue operation has finished.
* @return
* - n: Actual number of objects enqueued.
*/
static __rte_always_inline unsigned int
rte_ring_sp_enqueue_burst(struct rte_ring *r, void * const *obj_table,
unsigned int n, unsigned int *free_space)
{
return __rte_ring_do_enqueue(r, obj_table, n,
RTE_RING_QUEUE_VARIABLE, RTE_RING_SYNC_ST, free_space);
}
/**
* Enqueue several objects on a ring.
*
* This function calls the multi-producer or the single-producer
* version depending on the default behavior that was specified at
* ring creation time (see flags).
*
* @param r
* A pointer to the ring structure.
* @param obj_table
* A pointer to a table of void * pointers (objects).
* @param n
* The number of objects to add in the ring from the obj_table.
* @param free_space
* if non-NULL, returns the amount of space in the ring after the
* enqueue operation has finished.
* @return
* - n: Actual number of objects enqueued.
*/
static __rte_always_inline unsigned int
rte_ring_enqueue_burst(struct rte_ring *r, void * const *obj_table,
unsigned int n, unsigned int *free_space)
{
switch (r->prod.sync_type) {
case RTE_RING_SYNC_MT:
return rte_ring_mp_enqueue_burst(r, obj_table, n, free_space);
case RTE_RING_SYNC_ST:
return rte_ring_sp_enqueue_burst(r, obj_table, n, free_space);
#ifdef ALLOW_EXPERIMENTAL_API
case RTE_RING_SYNC_MT_RTS:
return rte_ring_mp_rts_enqueue_burst(r, obj_table, n,
free_space);
case RTE_RING_SYNC_MT_HTS:
return rte_ring_mp_hts_enqueue_burst(r, obj_table, n,
free_space);
#endif
}
/* valid ring should never reach this point */
RTE_ASSERT(0);
return 0;
}
/**
* Dequeue several objects from a ring (multi-consumers safe). When the request
* objects are more than the available objects, only dequeue the actual number
* of objects
*
* This function uses a "compare and set" instruction to move the
* consumer index atomically.
*
* @param r
* A pointer to the ring structure.
* @param obj_table
* A pointer to a table of void * pointers (objects) that will be filled.
* @param n
* The number of objects to dequeue from the ring to the obj_table.
* @param available
* If non-NULL, returns the number of remaining ring entries after the
* dequeue has finished.
* @return
* - n: Actual number of objects dequeued, 0 if ring is empty
*/
static __rte_always_inline unsigned int
rte_ring_mc_dequeue_burst(struct rte_ring *r, void **obj_table,
unsigned int n, unsigned int *available)
{
return __rte_ring_do_dequeue(r, obj_table, n,
RTE_RING_QUEUE_VARIABLE, RTE_RING_SYNC_MT, available);
}
/**
* Dequeue several objects from a ring (NOT multi-consumers safe).When the
* request objects are more than the available objects, only dequeue the
* actual number of objects
*
* @param r
* A pointer to the ring structure.
* @param obj_table
* A pointer to a table of void * pointers (objects) that will be filled.
* @param n
* The number of objects to dequeue from the ring to the obj_table.
* @param available
* If non-NULL, returns the number of remaining ring entries after the
* dequeue has finished.
* @return
* - n: Actual number of objects dequeued, 0 if ring is empty
*/
static __rte_always_inline unsigned int
rte_ring_sc_dequeue_burst(struct rte_ring *r, void **obj_table,
unsigned int n, unsigned int *available)
{
return __rte_ring_do_dequeue(r, obj_table, n,
RTE_RING_QUEUE_VARIABLE, RTE_RING_SYNC_ST, available);
}
/**
* Dequeue multiple objects from a ring up to a maximum number.
*
* This function calls the multi-consumers or the single-consumer
* version, depending on the default behaviour that was specified at
* ring creation time (see flags).
*
* @param r
* A pointer to the ring structure.
* @param obj_table
* A pointer to a table of void * pointers (objects) that will be filled.
* @param n
* The number of objects to dequeue from the ring to the obj_table.
* @param available
* If non-NULL, returns the number of remaining ring entries after the
* dequeue has finished.
* @return
* - Number of objects dequeued
*/
static __rte_always_inline unsigned int
rte_ring_dequeue_burst(struct rte_ring *r, void **obj_table,
unsigned int n, unsigned int *available)
{
switch (r->cons.sync_type) {
case RTE_RING_SYNC_MT:
return rte_ring_mc_dequeue_burst(r, obj_table, n, available);
case RTE_RING_SYNC_ST:
return rte_ring_sc_dequeue_burst(r, obj_table, n, available);
#ifdef ALLOW_EXPERIMENTAL_API
case RTE_RING_SYNC_MT_RTS:
return rte_ring_mc_rts_dequeue_burst(r, obj_table, n,
available);
case RTE_RING_SYNC_MT_HTS:
return rte_ring_mc_hts_dequeue_burst(r, obj_table, n,
available);
#endif
}
/* valid ring should never reach this point */
RTE_ASSERT(0);
return 0;
}
#ifdef __cplusplus
}
#endif
#endif /* _RTE_RING_H_ */