#include <stdio.h>
#include <stdint.h>
#include <sys/queue.h>
#include <errno.h>
#include <rte_common.h>
#include <rte_memory.h>
#include <rte_lcore.h>
#include <rte_atomic.h>
#include <rte_branch_prediction.h>
#include <rte_memzone.h>

Data Structures
struct	rte_ring

Macros
#define	RTE_RING_MZ_PREFIX "RG_"
#define	RING_F_SP_ENQ 0x0001
#define	RING_F_SC_DEQ 0x0002
#define	RTE_RING_SZ_MASK (unsigned)(0x0fffffff)

Functions
ssize_t	rte_ring_get_memsize (unsigned count)
int	rte_ring_init (struct rte_ring r, const char name, unsigned count, unsigned flags)
struct rte_ring *	rte_ring_create (const char *name, unsigned count, int socket_id, unsigned flags)
void	rte_ring_free (struct rte_ring *r)
void	rte_ring_dump (FILE f, const struct rte_ring r)
static unsigned int	rte_ring_mp_enqueue_bulk (struct rte_ring r, void const obj_table, unsigned int n, unsigned int free_space)
static unsigned int	rte_ring_sp_enqueue_bulk (struct rte_ring r, void const obj_table, unsigned int n, unsigned int free_space)
static unsigned int	rte_ring_enqueue_bulk (struct rte_ring r, void const obj_table, unsigned int n, unsigned int free_space)
static int	rte_ring_mp_enqueue (struct rte_ring r, void obj)
static int	rte_ring_sp_enqueue (struct rte_ring r, void obj)
static int	rte_ring_enqueue (struct rte_ring r, void obj)
static unsigned int	rte_ring_mc_dequeue_bulk (struct rte_ring r, void obj_table, unsigned int n, unsigned int available)
static unsigned int	rte_ring_sc_dequeue_bulk (struct rte_ring r, void obj_table, unsigned int n, unsigned int available)
static unsigned int	rte_ring_dequeue_bulk (struct rte_ring r, void obj_table, unsigned int n, unsigned int available)
static int	rte_ring_mc_dequeue (struct rte_ring r, void *obj_p)
static int	rte_ring_sc_dequeue (struct rte_ring r, void *obj_p)
static int	rte_ring_dequeue (struct rte_ring r, void *obj_p)
static int	rte_ring_full (const struct rte_ring *r)
static int	rte_ring_empty (const struct rte_ring *r)
static unsigned	rte_ring_count (const struct rte_ring *r)
static unsigned	rte_ring_free_count (const struct rte_ring *r)
static unsigned int	rte_ring_get_size (const struct rte_ring *r)
void	rte_ring_list_dump (FILE *f)
struct rte_ring *	rte_ring_lookup (const char *name)
static unsigned	rte_ring_mp_enqueue_burst (struct rte_ring r, void const obj_table, unsigned int n, unsigned int free_space)
static unsigned	rte_ring_sp_enqueue_burst (struct rte_ring r, void const obj_table, unsigned int n, unsigned int free_space)
static unsigned	rte_ring_enqueue_burst (struct rte_ring r, void const obj_table, unsigned int n, unsigned int free_space)
static unsigned	rte_ring_mc_dequeue_burst (struct rte_ring r, void obj_table, unsigned int n, unsigned int available)
static unsigned	rte_ring_sc_dequeue_burst (struct rte_ring r, void obj_table, unsigned int n, unsigned int available)
static unsigned	rte_ring_dequeue_burst (struct rte_ring r, void obj_table, unsigned int n, unsigned int available)

Detailed Description

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.

Note: the ring implementation is not preemptable. A lcore must not be interrupted by another task that uses the same ring.

Definition in file rte_ring.h.

Macro Definition Documentation

#define RTE_RING_MZ_PREFIX "RG_"

The maximum length of a ring name.

Definition at line 112 of file rte_ring.h.

#define RING_F_SP_ENQ 0x0001

The default enqueue is "single-producer".

Examples:: examples/distributor/main.c, examples/ip_pipeline/init.c, examples/load_balancer/init.c, examples/multi_process/client_server_mp/mp_server/init.c, examples/multi_process/l2fwd_fork/main.c, examples/packet_ordering/main.c, examples/performance-thread/l3fwd-thread/main.c, examples/qos_sched/init.c, examples/quota_watermark/qw/init.c, and examples/server_node_efd/server/init.c.

Definition at line 164 of file rte_ring.h.

#define RING_F_SC_DEQ 0x0002

The default dequeue is "single-consumer".

Examples:: examples/distributor/main.c, examples/ip_pipeline/init.c, examples/load_balancer/init.c, examples/multi_process/client_server_mp/mp_server/init.c, examples/multi_process/l2fwd_fork/main.c, examples/packet_ordering/main.c, examples/performance-thread/l3fwd-thread/main.c, examples/qos_sched/init.c, examples/quota_watermark/qw/init.c, and examples/server_node_efd/server/init.c.

Definition at line 165 of file rte_ring.h.

#define RTE_RING_SZ_MASK (unsigned)(0x0fffffff)

Ring size mask

Definition at line 166 of file rte_ring.h.

Function Documentation

ssize_t rte_ring_get_memsize ( unsigned count )

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.

Parameters

count The number of elements in the ring (must be a power of 2).

Returns

The memory size needed for the ring on success.
-EINVAL if count is not a power of 2.

int rte_ring_init	(	struct rte_ring *	r,
		const char *	name,
		unsigned	count,
		unsigned	flags
	)

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.

Parameters

r	The pointer to the ring structure followed by the objects table.
name	The name of the ring.
count	The number of elements in the ring (must be a power of 2).
flags	An OR of the following: 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". Otherwise, it is "multi-producers". 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".

Returns: 0 on success, or a negative value on error.

struct rte_ring* rte_ring_create	(	const char *	name,
		unsigned	count,
		int	socket_id,
		unsigned	flags
	)

read

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.

Parameters

name	The name of the ring.
count	The size of the ring (must be a power of 2).
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.
flags	An OR of the following: 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". Otherwise, it is "multi-producers". 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".

Returns

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

Examples:: examples/distributor/main.c, examples/ip_pipeline/init.c, examples/load_balancer/init.c, examples/multi_process/client_server_mp/mp_server/init.c, examples/multi_process/l2fwd_fork/main.c, examples/multi_process/simple_mp/main.c, examples/packet_ordering/main.c, examples/performance-thread/common/lthread_tls.c, examples/performance-thread/l3fwd-thread/main.c, examples/qos_sched/init.c, examples/quota_watermark/qw/init.c, and examples/server_node_efd/server/init.c.

void rte_ring_free ( struct rte_ring * r )

De-allocate all memory used by the ring.

Parameters

r	Ring to free

void rte_ring_dump	(	FILE *	f,
		const struct rte_ring *	r
	)

Dump the status of the ring to a file.

Parameters

f	A pointer to a file for output
r	A pointer to the ring structure.

Examples:: examples/quota_watermark/qwctl/commands.c.

static unsigned int rte_ring_mp_enqueue_bulk	(	struct rte_ring *	r,
		void const	obj_table,
		unsigned int	n,
		unsigned int *	free_space
	)

inlinestatic

Enqueue several objects on the ring (multi-producers safe).

This function uses a "compare and set" instruction to move the producer index atomically.

Parameters

r	A pointer to the ring structure.
obj_table	A pointer to a table of void * pointers (objects).
n	The number of objects to add in the ring from the obj_table.
free_space	if non-NULL, returns the amount of space in the ring after the enqueue operation has finished.

Returns: The number of objects enqueued, either 0 or n

Definition at line 594 of file rte_ring.h.

static unsigned int rte_ring_sp_enqueue_bulk	(	struct rte_ring *	r,
		void const	obj_table,
		unsigned int	n,
		unsigned int *	free_space
	)

inlinestatic

Enqueue several objects on a ring (NOT multi-producers safe).

Parameters

r	A pointer to the ring structure.
obj_table	A pointer to a table of void * pointers (objects).
n	The number of objects to add in the ring from the obj_table.
free_space	if non-NULL, returns the amount of space in the ring after the enqueue operation has finished.

Returns: The number of objects enqueued, either 0 or n

Examples:: examples/load_balancer/runtime.c, and examples/qos_sched/app_thread.c.

Definition at line 617 of file rte_ring.h.

static unsigned int rte_ring_enqueue_bulk	(	struct rte_ring *	r,
		void const	obj_table,
		unsigned int	n,
		unsigned int *	free_space
	)

inlinestatic

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).

Parameters

r	A pointer to the ring structure.
obj_table	A pointer to a table of void * pointers (objects).
n	The number of objects to add in the ring from the obj_table.
free_space	if non-NULL, returns the amount of space in the ring after the enqueue operation has finished.

Returns: The number of objects enqueued, either 0 or n

Examples:: examples/multi_process/client_server_mp/mp_server/main.c, examples/quota_watermark/qw/main.c, and examples/server_node_efd/server/main.c.

Definition at line 644 of file rte_ring.h.

static int rte_ring_mp_enqueue	(	struct rte_ring *	r,
		void *	obj
	)

inlinestatic

Enqueue one object on a ring (multi-producers safe).

This function uses a "compare and set" instruction to move the producer index atomically.

Parameters

r	A pointer to the ring structure.
obj	A pointer to the object to be added.

Returns

0: Success; objects enqueued.
-ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.

Examples:: examples/performance-thread/common/lthread_tls.c.

Definition at line 666 of file rte_ring.h.

static int rte_ring_sp_enqueue	(	struct rte_ring *	r,
		void *	obj
	)

inlinestatic

Enqueue one object on a ring (NOT multi-producers safe).

Parameters

r	A pointer to the ring structure.
obj	A pointer to the object to be added.

Returns

0: Success; objects enqueued.
-ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.

Examples:: examples/ip_pipeline/thread.c, and examples/ip_pipeline/thread_fe.c.

Definition at line 683 of file rte_ring.h.

static int rte_ring_enqueue	(	struct rte_ring *	r,
		void *	obj
	)

inlinestatic

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).

Parameters

r	A pointer to the ring structure.
obj	A pointer to the object to be added.

Returns

0: Success; objects enqueued.
-ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.

Examples:: examples/multi_process/l2fwd_fork/main.c, and examples/multi_process/simple_mp/mp_commands.c.

Definition at line 704 of file rte_ring.h.

static unsigned int rte_ring_mc_dequeue_bulk	(	struct rte_ring *	r,
		void **	obj_table,
		unsigned int	n,
		unsigned int *	available
	)

inlinestatic

Dequeue several objects from a ring (multi-consumers safe).

This function uses a "compare and set" instruction to move the consumer index atomically.

Parameters

r	A pointer to the ring structure.
obj_table	A pointer to a table of void * pointers (objects) that will be filled.
n	The number of objects to dequeue from the ring to the obj_table.
available	If non-NULL, returns the number of remaining ring entries after the dequeue has finished.

Returns: The number of objects dequeued, either 0 or n

Definition at line 728 of file rte_ring.h.

static unsigned int rte_ring_sc_dequeue_bulk	(	struct rte_ring *	r,
		void **	obj_table,
		unsigned int	n,
		unsigned int *	available
	)

inlinestatic

Dequeue several objects from a ring (NOT multi-consumers safe).

Parameters

r	A pointer to the ring structure.
obj_table	A pointer to a table of void * pointers (objects) that will be filled.
n	The number of objects to dequeue from the ring to the obj_table, must be strictly positive.
available	If non-NULL, returns the number of remaining ring entries after the dequeue has finished.

Returns: The number of objects dequeued, either 0 or n

Examples:: examples/load_balancer/runtime.c, and examples/qos_sched/app_thread.c.

Definition at line 752 of file rte_ring.h.

static unsigned int rte_ring_dequeue_bulk	(	struct rte_ring *	r,
		void **	obj_table,
		unsigned int	n,
		unsigned int *	available
	)

inlinestatic

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).

Parameters

r	A pointer to the ring structure.
obj_table	A pointer to a table of void * pointers (objects) that will be filled.
n	The number of objects to dequeue from the ring to the obj_table.
available	If non-NULL, returns the number of remaining ring entries after the dequeue has finished.

Returns: The number of objects dequeued, either 0 or n

Examples:: examples/server_node_efd/node/node.c.

Definition at line 779 of file rte_ring.h.

static int rte_ring_mc_dequeue	(	struct rte_ring *	r,
		void **	obj_p
	)

inlinestatic

Dequeue one object from a ring (multi-consumers safe).

This function uses a "compare and set" instruction to move the consumer index atomically.

Parameters

r	A pointer to the ring structure.
obj_p	A pointer to a void * pointer (object) that will be filled.

Returns

0: Success; objects dequeued.
-ENOENT: Not enough entries in the ring to dequeue; no object is dequeued.

Examples:: examples/performance-thread/common/lthread_tls.c.

Definition at line 802 of file rte_ring.h.

static int rte_ring_sc_dequeue	(	struct rte_ring *	r,
		void **	obj_p
	)

inlinestatic

Dequeue one object from a ring (NOT multi-consumers safe).

Parameters

r	A pointer to the ring structure.
obj_p	A pointer to a void * pointer (object) that will be filled.

Returns

0: Success; objects dequeued.
-ENOENT: Not enough entries in the ring to dequeue, no object is dequeued.

Examples:: examples/ip_pipeline/thread.c, and examples/ip_pipeline/thread_fe.c.

Definition at line 820 of file rte_ring.h.

static int rte_ring_dequeue	(	struct rte_ring *	r,
		void **	obj_p
	)

inlinestatic

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).

Parameters

r	A pointer to the ring structure.
obj_p	A pointer to a void * pointer (object) that will be filled.

Returns

0: Success, objects dequeued.
-ENOENT: Not enough entries in the ring to dequeue, no object is dequeued.

Examples:: examples/multi_process/l2fwd_fork/main.c, and examples/multi_process/simple_mp/main.c.

Definition at line 842 of file rte_ring.h.

static int rte_ring_full ( const struct rte_ring * r )

inlinestatic

Test if a ring is full.

Parameters

r	A pointer to the ring structure.

Returns

1: The ring is full.
0: The ring is not full.

Definition at line 857 of file rte_ring.h.

static int rte_ring_empty ( const struct rte_ring * r )

inlinestatic

Test if a ring is empty.

Parameters

r	A pointer to the ring structure.

Returns

1: The ring is empty.
0: The ring is not empty.

Examples:: examples/quota_watermark/qw/main.c.

Definition at line 874 of file rte_ring.h.

static unsigned rte_ring_count ( const struct rte_ring * r )

inlinestatic

Return the number of entries in a ring.

Parameters

r	A pointer to the ring structure.

Returns: The number of entries in the ring.

Examples:: examples/quota_watermark/qw/main.c, and examples/server_node_efd/node/node.c.

Definition at line 890 of file rte_ring.h.

static unsigned rte_ring_free_count ( const struct rte_ring * r )

inlinestatic

Return the number of free entries in a ring.

Parameters

r	A pointer to the ring structure.

Returns: The number of free entries in the ring.

Definition at line 906 of file rte_ring.h.

static unsigned int rte_ring_get_size ( const struct rte_ring * r )

inlinestatic

Return the size of the ring.

Parameters

r	A pointer to the ring structure.

Returns: The number of elements which can be stored in the ring.

Definition at line 922 of file rte_ring.h.

void rte_ring_list_dump ( FILE * f )

Dump the status of all rings on the console

Parameters

f	A pointer to a file for output

struct rte_ring* rte_ring_lookup ( const char * name )

read

Search a ring from its name

Parameters

name	The name of the ring.

Returns

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.

Examples:: examples/multi_process/client_server_mp/mp_client/client.c, examples/multi_process/l2fwd_fork/main.c, examples/multi_process/simple_mp/main.c, examples/qos_sched/init.c, examples/quota_watermark/qwctl/commands.c, and examples/server_node_efd/node/node.c.

static unsigned rte_ring_mp_enqueue_burst	(	struct rte_ring *	r,
		void const	obj_table,
		unsigned int	n,
		unsigned int *	free_space
	)

inlinestatic

Enqueue several objects on the ring (multi-producers safe).

This function uses a "compare and set" instruction to move the producer index atomically.

Parameters

r	A pointer to the ring structure.
obj_table	A pointer to a table of void * pointers (objects).
n	The number of objects to add in the ring from the obj_table.
free_space	if non-NULL, returns the amount of space in the ring after the enqueue operation has finished.

Returns

n: Actual number of objects enqueued.

Definition at line 966 of file rte_ring.h.

static unsigned rte_ring_sp_enqueue_burst	(	struct rte_ring *	r,
		void const	obj_table,
		unsigned int	n,
		unsigned int *	free_space
	)

inlinestatic

Enqueue several objects on a ring (NOT multi-producers safe).

Parameters

r	A pointer to the ring structure.
obj_table	A pointer to a table of void * pointers (objects).
n	The number of objects to add in the ring from the obj_table.
free_space	if non-NULL, returns the amount of space in the ring after the enqueue operation has finished.

Returns

n: Actual number of objects enqueued.

Examples:: examples/performance-thread/l3fwd-thread/main.c.

Definition at line 989 of file rte_ring.h.

static unsigned rte_ring_enqueue_burst	(	struct rte_ring *	r,
		void const	obj_table,
		unsigned int	n,
		unsigned int *	free_space
	)

inlinestatic

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).

Parameters

r	A pointer to the ring structure.
obj_table	A pointer to a table of void * pointers (objects).
n	The number of objects to add in the ring from the obj_table.
free_space	if non-NULL, returns the amount of space in the ring after the enqueue operation has finished.

Returns

n: Actual number of objects enqueued.

Examples:: examples/distributor/main.c, and examples/packet_ordering/main.c.

Definition at line 1016 of file rte_ring.h.

static unsigned rte_ring_mc_dequeue_burst	(	struct rte_ring *	r,
		void **	obj_table,
		unsigned int	n,
		unsigned int *	available
	)

inlinestatic

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.

Parameters

r	A pointer to the ring structure.
obj_table	A pointer to a table of void * pointers (objects) that will be filled.
n	The number of objects to dequeue from the ring to the obj_table.
available	If non-NULL, returns the number of remaining ring entries after the dequeue has finished.

Returns

n: Actual number of objects dequeued, 0 if ring is empty

Definition at line 1044 of file rte_ring.h.

static unsigned rte_ring_sc_dequeue_burst	(	struct rte_ring *	r,
		void **	obj_table,
		unsigned int	n,
		unsigned int *	available
	)

inlinestatic

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

Parameters

r	A pointer to the ring structure.
obj_table	A pointer to a table of void * pointers (objects) that will be filled.
n	The number of objects to dequeue from the ring to the obj_table.
available	If non-NULL, returns the number of remaining ring entries after the dequeue has finished.

Returns

n: Actual number of objects dequeued, 0 if ring is empty

Examples:: examples/performance-thread/l3fwd-thread/main.c, and examples/qos_sched/app_thread.c.

Definition at line 1069 of file rte_ring.h.

static unsigned rte_ring_dequeue_burst	(	struct rte_ring *	r,
		void **	obj_table,
		unsigned int	n,
		unsigned int *	available
	)

inlinestatic

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).

Parameters

r	A pointer to the ring structure.
obj_table	A pointer to a table of void * pointers (objects) that will be filled.
n	The number of objects to dequeue from the ring to the obj_table.
available	If non-NULL, returns the number of remaining ring entries after the dequeue has finished.

Returns

Number of objects dequeued

Examples:: examples/distributor/main.c, examples/multi_process/client_server_mp/mp_client/client.c, examples/packet_ordering/main.c, and examples/quota_watermark/qw/main.c.

Definition at line 1096 of file rte_ring.h.

Data Structures

Macros

Functions

Detailed Description

Macro Definition Documentation

Function Documentation