#include <rte_lcore.h>
#include <rte_atomic.h>
#include <rte_branch_prediction.h>
+#include <rte_memzone.h>
+
+#define RTE_TAILQ_RING_NAME "RTE_RING"
enum rte_ring_queue_behavior {
RTE_RING_QUEUE_FIXED = 0, /* Enq/Deq a fixed number of items from a ring */
- RTE_RING_QUEUE_VARIABLE /* Enq/Deq as many items a possible from ring */
+ RTE_RING_QUEUE_VARIABLE /* Enq/Deq as many items as possible from ring */
};
#ifdef RTE_LIBRTE_RING_DEBUG
} __rte_cache_aligned;
#endif
-#define RTE_RING_NAMESIZE 32 /**< The maximum length of a ring name. */
#define RTE_RING_MZ_PREFIX "RG_"
+/**< The maximum length of a ring name. */
+#define RTE_RING_NAMESIZE (RTE_MEMZONE_NAMESIZE - \
+ sizeof(RTE_RING_MZ_PREFIX) + 1)
+
+#ifndef RTE_RING_PAUSE_REP_COUNT
+#define RTE_RING_PAUSE_REP_COUNT 0 /**< Yield after pause num of times, no yield
+ * if RTE_RING_PAUSE_REP not defined. */
+#endif
+
+struct rte_memzone; /* forward declaration, so as not to require memzone.h */
+
+#if RTE_CACHE_LINE_SIZE < 128
+#define PROD_ALIGN (RTE_CACHE_LINE_SIZE * 2)
+#define CONS_ALIGN (RTE_CACHE_LINE_SIZE * 2)
+#else
+#define PROD_ALIGN RTE_CACHE_LINE_SIZE
+#define CONS_ALIGN RTE_CACHE_LINE_SIZE
+#endif
/**
* An RTE ring structure.
* a problem.
*/
struct rte_ring {
- char name[RTE_RING_NAMESIZE]; /**< Name of the ring. */
+ /*
+ * Note: this field kept the RTE_MEMZONE_NAMESIZE size due to ABI
+ * compatibility requirements, it could be changed to RTE_RING_NAMESIZE
+ * next time the ABI changes
+ */
+ char name[RTE_MEMZONE_NAMESIZE]; /**< Name of the ring. */
int flags; /**< Flags supplied at creation. */
+ const struct rte_memzone *memzone;
+ /**< Memzone, if any, containing the rte_ring */
/** Ring producer status. */
struct prod {
uint32_t mask; /**< Mask (size-1) of ring. */
volatile uint32_t head; /**< Producer head. */
volatile uint32_t tail; /**< Producer tail. */
- } prod __rte_cache_aligned;
+ } prod __rte_aligned(PROD_ALIGN);
/** Ring consumer status. */
struct cons {
uint32_t mask; /**< Mask (size-1) of ring. */
volatile uint32_t head; /**< Consumer head. */
volatile uint32_t tail; /**< Consumer tail. */
-#ifdef RTE_RING_SPLIT_PROD_CONS
- } cons __rte_cache_aligned;
-#else
- } cons;
-#endif
+ } cons __rte_aligned(CONS_ALIGN);
#ifdef RTE_LIBRTE_RING_DEBUG
struct rte_ring_debug_stats stats[RTE_MAX_LCORE];
#endif
- void * ring[0] __rte_cache_aligned; /**< Memory space of ring starts here.
+ void *ring[] __rte_cache_aligned; /**< Memory space of ring starts here.
* not volatile so need to be careful
* about compiler re-ordering */
};
* 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
- * - E_RTE_NO_TAILQ - no tailq list could be got for the ring list
* - 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
*/
struct rte_ring *rte_ring_create(const char *name, unsigned count,
int socket_id, unsigned flags);
+/**
+ * De-allocate all memory used by the ring.
+ *
+ * @param r
+ * Ring to free
+ */
+void rte_ring_free(struct rte_ring *r);
/**
* Change the high water mark.
int rte_ring_set_water_mark(struct rte_ring *r, unsigned count);
/**
- * Dump the status of the ring to the console.
+ * Dump the status of the ring to a file.
*
* @param f
* A pointer to a file for output
uint32_t cons_tail, free_entries;
const unsigned max = n;
int success;
- unsigned i;
+ unsigned i, rep = 0;
uint32_t mask = r->prod.mask;
int ret;
+ /* Avoid the unnecessary cmpset operation below, which is also
+ * potentially harmful when n equals 0. */
+ if (n == 0)
+ return 0;
+
/* move prod.head atomically */
do {
/* Reset n to the initial burst count */
/* write entries in ring */
ENQUEUE_PTRS();
- rte_compiler_barrier();
+ rte_smp_wmb();
/* if we exceed the watermark */
if (unlikely(((mask + 1) - free_entries + n) > r->prod.watermark)) {
* If there are other enqueues in progress that preceded us,
* we need to wait for them to complete
*/
- while (unlikely(r->prod.tail != prod_head))
+ while (unlikely(r->prod.tail != prod_head)) {
rte_pause();
+ /* Set RTE_RING_PAUSE_REP_COUNT to avoid spin too long waiting
+ * for other thread finish. It gives pre-empted thread a chance
+ * to proceed and finish with ring dequeue operation. */
+ if (RTE_RING_PAUSE_REP_COUNT &&
+ ++rep == RTE_RING_PAUSE_REP_COUNT) {
+ rep = 0;
+ sched_yield();
+ }
+ }
r->prod.tail = prod_next;
return ret;
}
/* write entries in ring */
ENQUEUE_PTRS();
- rte_compiler_barrier();
+ rte_smp_wmb();
/* if we exceed the watermark */
if (unlikely(((mask + 1) - free_entries + n) > r->prod.watermark)) {
uint32_t cons_next, entries;
const unsigned max = n;
int success;
- unsigned i;
+ unsigned i, rep = 0;
uint32_t mask = r->prod.mask;
+ /* Avoid the unnecessary cmpset operation below, which is also
+ * potentially harmful when n equals 0. */
+ if (n == 0)
+ return 0;
+
/* move cons.head atomically */
do {
/* Restore n as it may change every loop */
/* copy in table */
DEQUEUE_PTRS();
- rte_compiler_barrier();
+ rte_smp_rmb();
/*
* If there are other dequeues in progress that preceded us,
* we need to wait for them to complete
*/
- while (unlikely(r->cons.tail != cons_head))
+ while (unlikely(r->cons.tail != cons_head)) {
rte_pause();
+ /* Set RTE_RING_PAUSE_REP_COUNT to avoid spin too long waiting
+ * for other thread finish. It gives pre-empted thread a chance
+ * to proceed and finish with ring dequeue operation. */
+ if (RTE_RING_PAUSE_REP_COUNT &&
+ ++rep == RTE_RING_PAUSE_REP_COUNT) {
+ rep = 0;
+ sched_yield();
+ }
+ }
__RING_STAT_ADD(r, deq_success, n);
r->cons.tail = cons_next;
/* copy in table */
DEQUEUE_PTRS();
- rte_compiler_barrier();
+ rte_smp_rmb();
__RING_STAT_ADD(r, deq_success, n);
r->cons.tail = cons_next;
{
uint32_t prod_tail = r->prod.tail;
uint32_t cons_tail = r->cons.tail;
- return (((cons_tail - prod_tail - 1) & r->prod.mask) == 0);
+ return ((cons_tail - prod_tail - 1) & r->prod.mask) == 0;
}
/**
{
uint32_t prod_tail = r->prod.tail;
uint32_t cons_tail = r->cons.tail;
- return ((prod_tail - cons_tail) & r->prod.mask);
+ return (prod_tail - cons_tail) & r->prod.mask;
}
/**
{
uint32_t prod_tail = r->prod.tail;
uint32_t cons_tail = r->cons.tail;
- return ((cons_tail - prod_tail - 1) & r->prod.mask);
+ return (cons_tail - prod_tail - 1) & r->prod.mask;
+}
+
+/**
+ * Return the size of the ring.
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @return
+ * The number of elements which can be stored in the ring.
+ */
+static inline unsigned int
+rte_ring_get_size(const struct rte_ring *r)
+{
+ return r->prod.size;
}
/**
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