From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id 71EFFA034F; Wed, 13 May 2020 17:31:25 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 4E81B1D648; Wed, 13 May 2020 17:31:25 +0200 (CEST) Received: from smartserver.smartsharesystems.com (smartserver.smartsharesystems.com [77.243.40.215]) by dpdk.org (Postfix) with ESMTP id 62EC61D643 for ; Wed, 13 May 2020 17:31:24 +0200 (CEST) Received: from dkrd2.smartsharesys.local ([192.168.4.12]) by smartserver.smartsharesystems.com with Microsoft SMTPSVC(6.0.3790.4675); Wed, 13 May 2020 17:31:22 +0200 From: =?UTF-8?q?Morten=20Br=C3=B8rup?= To: olivier.matz@6wind.com, konstantin.ananyev@intel.com, Honnappa.Nagarahalli@arm.com, nd@arm.com Cc: dev@dpdk.org, =?UTF-8?q?Morten=20Br=C3=B8rup?= Date: Wed, 13 May 2020 15:31:11 +0000 Message-Id: <20200513153111.37063-1-mb@smartsharesystems.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-OriginalArrivalTime: 13 May 2020 15:31:22.0928 (UTC) FILETIME=[8EC7DB00:01D6293B] Subject: [dpdk-dev] [PATCH] ring: empty and count optimizations X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Testing if the ring is empty is as simple as comparing the producer and\nconsumer pointers.\nIn theory, this optimization reduces the number of potential cache misses\nfrom 3 to 2 by not having to read r->mask in rte_ring_count().\n\nIt is not possible to enqueue more elements than the capacity of a ring,\nso the capacity comparison is a safeguard for observer threads only.\nInstead of completely removing the comparison, I have reorganized it to\nresemble the other trigrahps in the ring library and added a likely().\n\nThe modification of these two functions were discussed in the RFC here:\nhttps://mails.dpdk.org/archives/dev/2020-April/165752.html Signed-off-by: Morten Brørup --- lib/librte_ring/rte_ring.h | 36 +++++++++++++++++++----------------- 1 file changed, 19 insertions(+), 17 deletions(-) diff --git a/lib/librte_ring/rte_ring.h b/lib/librte_ring/rte_ring.h index 86faede81..74a8fcdc8 100644 --- a/lib/librte_ring/rte_ring.h +++ b/lib/librte_ring/rte_ring.h @@ -55,7 +55,7 @@ extern "C" { * - 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 count); +ssize_t rte_ring_get_memsize(unsigned int count); /** * Initialize a ring structure. @@ -109,8 +109,8 @@ ssize_t rte_ring_get_memsize(unsigned count); * @return * 0 on success, or a negative value on error. */ -int rte_ring_init(struct rte_ring *r, const char *name, unsigned count, - unsigned flags); +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. @@ -169,8 +169,8 @@ int rte_ring_init(struct rte_ring *r, const char *name, unsigned count, * - 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 count, - int socket_id, unsigned flags); +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. @@ -199,7 +199,7 @@ void rte_ring_dump(FILE *f, const struct rte_ring *r); uint32_t idx = prod_head & (r)->mask; \ obj_type *ring = (obj_type *)ring_start; \ if (likely(idx + n < size)) { \ - for (i = 0; i < (n & ((~(unsigned)0x3))); i+=4, idx+=4) { \ + for (i = 0; i < (n & ((~(unsigned int)0x3))); i+=4, idx+=4) { \ ring[idx] = obj_table[i]; \ ring[idx+1] = obj_table[i+1]; \ ring[idx+2] = obj_table[i+2]; \ @@ -230,7 +230,7 @@ void rte_ring_dump(FILE *f, const struct rte_ring *r); const uint32_t size = (r)->size; \ obj_type *ring = (obj_type *)ring_start; \ if (likely(idx + n < size)) { \ - for (i = 0; i < (n & (~(unsigned)0x3)); i+=4, idx+=4) {\ + for (i = 0; i < (n & (~(unsigned int)0x3)); i+=4, idx+=4) {\ obj_table[i] = ring[idx]; \ obj_table[i+1] = ring[idx+1]; \ obj_table[i+2] = ring[idx+2]; \ @@ -683,13 +683,13 @@ rte_ring_reset(struct rte_ring *r); * @return * The number of entries in the ring. */ -static inline unsigned +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 likely(count <= r->capacity) ? count : r->capacity; } /** @@ -700,7 +700,7 @@ rte_ring_count(const struct rte_ring *r) * @return * The number of free entries in the ring. */ -static inline unsigned +static inline unsigned int rte_ring_free_count(const struct rte_ring *r) { return r->capacity - rte_ring_count(r); @@ -733,7 +733,9 @@ rte_ring_full(const struct rte_ring *r) static inline int rte_ring_empty(const struct rte_ring *r) { - return rte_ring_count(r) == 0; + uint32_t prod_tail = r->prod.tail; + uint32_t cons_tail = r->cons.tail; + return cons_tail == prod_tail; } /** @@ -860,7 +862,7 @@ struct rte_ring *rte_ring_lookup(const char *name); * @return * - n: Actual number of objects enqueued. */ -static __rte_always_inline unsigned +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) { @@ -883,7 +885,7 @@ rte_ring_mp_enqueue_burst(struct rte_ring *r, void * const *obj_table, * @return * - n: Actual number of objects enqueued. */ -static __rte_always_inline unsigned +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) { @@ -910,7 +912,7 @@ rte_ring_sp_enqueue_burst(struct rte_ring *r, void * const *obj_table, * @return * - n: Actual number of objects enqueued. */ -static __rte_always_inline unsigned +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) { @@ -954,7 +956,7 @@ rte_ring_enqueue_burst(struct rte_ring *r, void * const *obj_table, * @return * - n: Actual number of objects dequeued, 0 if ring is empty */ -static __rte_always_inline unsigned +static __rte_always_inline unsigned int rte_ring_mc_dequeue_burst(struct rte_ring *r, void **obj_table, unsigned int n, unsigned int *available) { @@ -979,7 +981,7 @@ rte_ring_mc_dequeue_burst(struct rte_ring *r, void **obj_table, * @return * - n: Actual number of objects dequeued, 0 if ring is empty */ -static __rte_always_inline unsigned +static __rte_always_inline unsigned int rte_ring_sc_dequeue_burst(struct rte_ring *r, void **obj_table, unsigned int n, unsigned int *available) { @@ -1006,7 +1008,7 @@ rte_ring_sc_dequeue_burst(struct rte_ring *r, void **obj_table, * @return * - Number of objects dequeued */ -static __rte_always_inline unsigned +static __rte_always_inline unsigned int rte_ring_dequeue_burst(struct rte_ring *r, void **obj_table, unsigned int n, unsigned int *available) { -- 2.17.1