From: Honnappa Nagarahalli Date: Sun, 25 Oct 2020 05:45:49 +0000 (-0500) Subject: ring: add zero copy API X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=47bec9a5ca9f0bb2726427ffbac462b2a82d69d1;p=dpdk.git ring: add zero copy API Add zero-copy APIs. These APIs provide the capability to copy the data to/from the ring memory directly, without having a temporary copy (for ex: an array of mbufs on the stack). Use cases that involve copying large amount of data to/from the ring can benefit from these APIs. Signed-off-by: Honnappa Nagarahalli Reviewed-by: Dharmik Thakkar Acked-by: Konstantin Ananyev --- diff --git a/doc/guides/prog_guide/ring_lib.rst b/doc/guides/prog_guide/ring_lib.rst index 895484d959..54e0bb4b68 100644 --- a/doc/guides/prog_guide/ring_lib.rst +++ b/doc/guides/prog_guide/ring_lib.rst @@ -452,6 +452,47 @@ selected. As an example of usage: Note that between ``_start_`` and ``_finish_`` none other thread can proceed with enqueue(/dequeue) operation till ``_finish_`` completes. +Ring Peek Zero Copy API +----------------------- + +Along with the advantages of the peek APIs, zero copy APIs provide the ability +to copy the data to the ring memory directly without the need for temporary +storage (for ex: array of mbufs on the stack). + +These APIs make it possible to split public enqueue/dequeue API into 3 phases: + +* enqueue/dequeue start + +* copy data to/from the ring + +* enqueue/dequeue finish + +Note that this API is available only for two sync modes: + +* Single Producer/Single Consumer (SP/SC) + +* Multi-producer/Multi-consumer with Head/Tail Sync (HTS) + +It is a user responsibility to create/init ring with appropriate sync modes. +Following is an example of usage: + +.. code-block:: c + + /* Reserve space on the ring */ + n = rte_ring_enqueue_zc_burst_start(r, 32, &zcd, NULL); + /* Pkt I/O core polls packets from the NIC */ + if (n != 0) { + nb_rx = rte_eth_rx_burst(portid, queueid, zcd->ptr1, zcd->n1); + if (nb_rx == zcd->n1 && n != zcd->n1) + nb_rx += rte_eth_rx_burst(portid, queueid, zcd->ptr2, + n - zcd->n1); + /* Provide packets to the packet processing cores */ + rte_ring_enqueue_zc_finish(r, nb_rx); + } + +Note that between ``_start_`` and ``_finish_`` no other thread can proceed +with enqueue(/dequeue) operation till ``_finish_`` completes. + References ---------- diff --git a/doc/guides/rel_notes/release_20_11.rst b/doc/guides/rel_notes/release_20_11.rst index c93a943607..bae39b2dd0 100644 --- a/doc/guides/rel_notes/release_20_11.rst +++ b/doc/guides/rel_notes/release_20_11.rst @@ -84,6 +84,15 @@ New Features ``rte_vect_set_max_simd_bitwidth`` function, or by the user with EAL flag ``--force-max-simd-bitwidth``. +* **Added zero copy APIs for rte_ring.** + + For rings with producer/consumer in ``RTE_RING_SYNC_ST``, ``RTE_RING_SYNC_MT_HTS`` + modes, these APIs split enqueue/dequeue operation into three phases + (enqueue/dequeue start, copy data to/from ring, enqueue/dequeue finish). + Along with the advantages of the peek APIs, these provide the ability to + copy the data to the ring memory directly without the need for temporary + storage. + * **Updated CRC modules of the net library.** * Added runtime selection of the optimal architecture-specific CRC path. diff --git a/lib/librte_ring/meson.build b/lib/librte_ring/meson.build index 31c0b46496..36fdcb6a57 100644 --- a/lib/librte_ring/meson.build +++ b/lib/librte_ring/meson.build @@ -11,5 +11,6 @@ headers = files('rte_ring.h', 'rte_ring_hts_c11_mem.h', 'rte_ring_peek.h', 'rte_ring_peek_c11_mem.h', + 'rte_ring_peek_zc.h', 'rte_ring_rts.h', 'rte_ring_rts_c11_mem.h') diff --git a/lib/librte_ring/rte_ring_elem.h b/lib/librte_ring/rte_ring_elem.h index 938b398fc0..7034d29c07 100644 --- a/lib/librte_ring/rte_ring_elem.h +++ b/lib/librte_ring/rte_ring_elem.h @@ -1079,6 +1079,7 @@ rte_ring_dequeue_burst_elem(struct rte_ring *r, void *obj_table, #ifdef ALLOW_EXPERIMENTAL_API #include +#include #endif #include diff --git a/lib/librte_ring/rte_ring_peek_zc.h b/lib/librte_ring/rte_ring_peek_zc.h new file mode 100644 index 0000000000..cb3bbd0678 --- /dev/null +++ b/lib/librte_ring/rte_ring_peek_zc.h @@ -0,0 +1,549 @@ +/* SPDX-License-Identifier: BSD-3-Clause + * + * Copyright (c) 2020 Arm Limited + * 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_PEEK_ZC_H_ +#define _RTE_RING_PEEK_ZC_H_ + +/** + * @file + * @b EXPERIMENTAL: this API may change without prior notice + * It is not recommended to include this file directly. + * Please include instead. + * + * Ring Peek Zero Copy APIs + * These APIs make it possible to split public enqueue/dequeue API + * into 3 parts: + * - enqueue/dequeue start + * - copy data to/from the ring + * - enqueue/dequeue finish + * Along with the advantages of the peek APIs, these APIs provide the ability + * to avoid copying of the data to temporary area (for ex: array of mbufs + * on the stack). + * + * Note that currently these APIs are available only for two sync modes: + * 1) Single Producer/Single Consumer (RTE_RING_SYNC_ST) + * 2) Serialized Producer/Serialized Consumer (RTE_RING_SYNC_MT_HTS). + * It is user's responsibility to create/init ring with appropriate sync + * modes selected. + * + * Following are some examples showing the API usage. + * 1) + * struct elem_obj {uint64_t a; uint32_t b, c;}; + * struct elem_obj *obj; + * + * // Create ring with sync type RTE_RING_SYNC_ST or RTE_RING_SYNC_MT_HTS + * // Reserve space on the ring + * n = rte_ring_enqueue_zc_bulk_elem_start(r, sizeof(elem_obj), 1, &zcd, NULL); + * + * // Produce the data directly on the ring memory + * obj = (struct elem_obj *)zcd->ptr1; + * obj->a = rte_get_a(); + * obj->b = rte_get_b(); + * obj->c = rte_get_c(); + * rte_ring_enqueue_zc_elem_finish(ring, n); + * + * 2) + * // Create ring with sync type RTE_RING_SYNC_ST or RTE_RING_SYNC_MT_HTS + * // Reserve space on the ring + * n = rte_ring_enqueue_zc_burst_start(r, 32, &zcd, NULL); + * + * // Pkt I/O core polls packets from the NIC + * if (n != 0) { + * nb_rx = rte_eth_rx_burst(portid, queueid, zcd->ptr1, zcd->n1); + * if (nb_rx == zcd->n1 && n != zcd->n1) + * nb_rx = rte_eth_rx_burst(portid, queueid, + * zcd->ptr2, n - zcd->n1); + * + * // Provide packets to the packet processing cores + * rte_ring_enqueue_zc_finish(r, nb_rx); + * } + * + * Note that between _start_ and _finish_ none other thread can proceed + * with enqueue/dequeue operation till _finish_ completes. + */ + +#ifdef __cplusplus +extern "C" { +#endif + +#include + +/** + * Ring zero-copy information structure. + * + * This structure contains the pointers and length of the space + * reserved on the ring storage. + */ +struct rte_ring_zc_data { + /* Pointer to the first space in the ring */ + void *ptr1; + /* Pointer to the second space in the ring if there is wrap-around. + * It contains valid value only if wrap-around happens. + */ + void *ptr2; + /* Number of elements in the first pointer. If this is equal to + * the number of elements requested, then ptr2 is NULL. + * Otherwise, subtracting n1 from number of elements requested + * will give the number of elements available at ptr2. + */ + unsigned int n1; +} __rte_cache_aligned; + +static __rte_always_inline void +__rte_ring_get_elem_addr(struct rte_ring *r, uint32_t head, + uint32_t esize, uint32_t num, void **dst1, uint32_t *n1, void **dst2) +{ + uint32_t idx, scale, nr_idx; + uint32_t *ring = (uint32_t *)&r[1]; + + /* Normalize to uint32_t */ + scale = esize / sizeof(uint32_t); + idx = head & r->mask; + nr_idx = idx * scale; + + *dst1 = ring + nr_idx; + *n1 = num; + + if (idx + num > r->size) { + *n1 = r->size - idx; + *dst2 = ring; + } else { + *dst2 = NULL; + } +} + +/** + * @internal This function moves prod head value. + */ +static __rte_always_inline unsigned int +__rte_ring_do_enqueue_zc_elem_start(struct rte_ring *r, unsigned int esize, + uint32_t n, enum rte_ring_queue_behavior behavior, + struct rte_ring_zc_data *zcd, unsigned int *free_space) +{ + uint32_t free, head, next; + + switch (r->prod.sync_type) { + case RTE_RING_SYNC_ST: + n = __rte_ring_move_prod_head(r, RTE_RING_SYNC_ST, n, + behavior, &head, &next, &free); + break; + case RTE_RING_SYNC_MT_HTS: + n = __rte_ring_hts_move_prod_head(r, n, behavior, &head, &free); + break; + case RTE_RING_SYNC_MT: + case RTE_RING_SYNC_MT_RTS: + default: + /* unsupported mode, shouldn't be here */ + RTE_ASSERT(0); + n = 0; + free = 0; + return n; + } + + __rte_ring_get_elem_addr(r, head, esize, n, &zcd->ptr1, + &zcd->n1, &zcd->ptr2); + + if (free_space != NULL) + *free_space = free - n; + return n; +} + +/** + * Start to enqueue several objects on the ring. + * Note that no actual objects are put in the queue by this function, + * it just reserves space for the user on the ring. + * User has to copy objects into the queue using the returned pointers. + * User should call rte_ring_enqueue_zc_elem_finish to complete the + * enqueue operation. + * + * @param r + * A pointer to the ring structure. + * @param esize + * The size of ring element, in bytes. It must be a multiple of 4. + * @param n + * The number of objects to add in the ring. + * @param zcd + * Structure containing the pointers and length of the space + * reserved on the ring storage. + * @param free_space + * If non-NULL, returns the amount of space in the ring after the + * reservation operation has finished. + * @return + * The number of objects that can be enqueued, either 0 or n + */ +__rte_experimental +static __rte_always_inline unsigned int +rte_ring_enqueue_zc_bulk_elem_start(struct rte_ring *r, unsigned int esize, + unsigned int n, struct rte_ring_zc_data *zcd, unsigned int *free_space) +{ + return __rte_ring_do_enqueue_zc_elem_start(r, esize, n, + RTE_RING_QUEUE_FIXED, zcd, free_space); +} + +/** + * Start to enqueue several pointers to objects on the ring. + * Note that no actual pointers are put in the queue by this function, + * it just reserves space for the user on the ring. + * User has to copy pointers to objects into the queue using the + * returned pointers. + * User should call rte_ring_enqueue_zc_finish to complete the + * enqueue operation. + * + * @param r + * A pointer to the ring structure. + * @param n + * The number of objects to add in the ring. + * @param zcd + * Structure containing the pointers and length of the space + * reserved on the ring storage. + * @param free_space + * If non-NULL, returns the amount of space in the ring after the + * reservation operation has finished. + * @return + * The number of objects that can be enqueued, either 0 or n + */ +__rte_experimental +static __rte_always_inline unsigned int +rte_ring_enqueue_zc_bulk_start(struct rte_ring *r, unsigned int n, + struct rte_ring_zc_data *zcd, unsigned int *free_space) +{ + return rte_ring_enqueue_zc_bulk_elem_start(r, sizeof(uintptr_t), n, + zcd, free_space); +} + +/** + * Start to enqueue several objects on the ring. + * Note that no actual objects are put in the queue by this function, + * it just reserves space for the user on the ring. + * User has to copy objects into the queue using the returned pointers. + * User should call rte_ring_enqueue_zc_elem_finish to complete the + * enqueue operation. + * + * @param r + * A pointer to the ring structure. + * @param esize + * The size of ring element, in bytes. It must be a multiple of 4. + * @param n + * The number of objects to add in the ring. + * @param zcd + * Structure containing the pointers and length of the space + * reserved on the ring storage. + * @param free_space + * If non-NULL, returns the amount of space in the ring after the + * reservation operation has finished. + * @return + * The number of objects that can be enqueued, either 0 or n + */ +__rte_experimental +static __rte_always_inline unsigned int +rte_ring_enqueue_zc_burst_elem_start(struct rte_ring *r, unsigned int esize, + unsigned int n, struct rte_ring_zc_data *zcd, unsigned int *free_space) +{ + return __rte_ring_do_enqueue_zc_elem_start(r, esize, n, + RTE_RING_QUEUE_VARIABLE, zcd, free_space); +} + +/** + * Start to enqueue several pointers to objects on the ring. + * Note that no actual pointers are put in the queue by this function, + * it just reserves space for the user on the ring. + * User has to copy pointers to objects into the queue using the + * returned pointers. + * User should call rte_ring_enqueue_zc_finish to complete the + * enqueue operation. + * + * @param r + * A pointer to the ring structure. + * @param n + * The number of objects to add in the ring. + * @param zcd + * Structure containing the pointers and length of the space + * reserved on the ring storage. + * @param free_space + * If non-NULL, returns the amount of space in the ring after the + * reservation operation has finished. + * @return + * The number of objects that can be enqueued, either 0 or n. + */ +__rte_experimental +static __rte_always_inline unsigned int +rte_ring_enqueue_zc_burst_start(struct rte_ring *r, unsigned int n, + struct rte_ring_zc_data *zcd, unsigned int *free_space) +{ + return rte_ring_enqueue_zc_burst_elem_start(r, sizeof(uintptr_t), n, + zcd, free_space); +} + +/** + * Complete enqueuing several objects on the ring. + * Note that number of objects to enqueue should not exceed previous + * enqueue_start return value. + * + * @param r + * A pointer to the ring structure. + * @param n + * The number of objects to add to the ring. + */ +__rte_experimental +static __rte_always_inline void +rte_ring_enqueue_zc_elem_finish(struct rte_ring *r, unsigned int n) +{ + uint32_t tail; + + switch (r->prod.sync_type) { + case RTE_RING_SYNC_ST: + n = __rte_ring_st_get_tail(&r->prod, &tail, n); + __rte_ring_st_set_head_tail(&r->prod, tail, n, 1); + break; + case RTE_RING_SYNC_MT_HTS: + n = __rte_ring_hts_get_tail(&r->hts_prod, &tail, n); + __rte_ring_hts_set_head_tail(&r->hts_prod, tail, n, 1); + break; + case RTE_RING_SYNC_MT: + case RTE_RING_SYNC_MT_RTS: + default: + /* unsupported mode, shouldn't be here */ + RTE_ASSERT(0); + } +} + +/** + * Complete enqueuing several pointers to objects on the ring. + * Note that number of objects to enqueue should not exceed previous + * enqueue_start return value. + * + * @param r + * A pointer to the ring structure. + * @param n + * The number of pointers to objects to add to the ring. + */ +__rte_experimental +static __rte_always_inline void +rte_ring_enqueue_zc_finish(struct rte_ring *r, unsigned int n) +{ + rte_ring_enqueue_zc_elem_finish(r, n); +} + +/** + * @internal This function moves cons head value and copies up to *n* + * objects from the ring to the user provided obj_table. + */ +static __rte_always_inline unsigned int +__rte_ring_do_dequeue_zc_elem_start(struct rte_ring *r, + uint32_t esize, uint32_t n, enum rte_ring_queue_behavior behavior, + struct rte_ring_zc_data *zcd, unsigned int *available) +{ + uint32_t avail, head, next; + + switch (r->cons.sync_type) { + case RTE_RING_SYNC_ST: + n = __rte_ring_move_cons_head(r, RTE_RING_SYNC_ST, n, + behavior, &head, &next, &avail); + break; + case RTE_RING_SYNC_MT_HTS: + n = __rte_ring_hts_move_cons_head(r, n, behavior, + &head, &avail); + break; + case RTE_RING_SYNC_MT: + case RTE_RING_SYNC_MT_RTS: + default: + /* unsupported mode, shouldn't be here */ + RTE_ASSERT(0); + n = 0; + avail = 0; + return n; + } + + __rte_ring_get_elem_addr(r, head, esize, n, &zcd->ptr1, + &zcd->n1, &zcd->ptr2); + + if (available != NULL) + *available = avail - n; + return n; +} + +/** + * Start to dequeue several objects from the ring. + * Note that no actual objects are copied from the queue by this function. + * User has to copy objects from the queue using the returned pointers. + * User should call rte_ring_dequeue_zc_elem_finish to complete the + * dequeue operation. + * + * @param r + * A pointer to the ring structure. + * @param esize + * The size of ring element, in bytes. It must be a multiple of 4. + * @param n + * The number of objects to remove from the ring. + * @param zcd + * Structure containing the pointers and length of the space + * reserved on the ring storage. + * @param available + * If non-NULL, returns the number of remaining ring entries after the + * dequeue has finished. + * @return + * The number of objects that can be dequeued, either 0 or n. + */ +__rte_experimental +static __rte_always_inline unsigned int +rte_ring_dequeue_zc_bulk_elem_start(struct rte_ring *r, unsigned int esize, + unsigned int n, struct rte_ring_zc_data *zcd, unsigned int *available) +{ + return __rte_ring_do_dequeue_zc_elem_start(r, esize, n, + RTE_RING_QUEUE_FIXED, zcd, available); +} + +/** + * Start to dequeue several pointers to objects from the ring. + * Note that no actual pointers are removed from the queue by this function. + * User has to copy pointers to objects from the queue using the + * returned pointers. + * User should call rte_ring_dequeue_zc_finish to complete the + * dequeue operation. + * + * @param r + * A pointer to the ring structure. + * @param n + * The number of objects to remove from the ring. + * @param zcd + * Structure containing the pointers and length of the space + * reserved on the ring storage. + * @param available + * If non-NULL, returns the number of remaining ring entries after the + * dequeue has finished. + * @return + * The number of objects that can be dequeued, either 0 or n. + */ +__rte_experimental +static __rte_always_inline unsigned int +rte_ring_dequeue_zc_bulk_start(struct rte_ring *r, unsigned int n, + struct rte_ring_zc_data *zcd, unsigned int *available) +{ + return rte_ring_dequeue_zc_bulk_elem_start(r, sizeof(uintptr_t), + n, zcd, available); +} + +/** + * Start to dequeue several objects from the ring. + * Note that no actual objects are copied from the queue by this function. + * User has to copy objects from the queue using the returned pointers. + * User should call rte_ring_dequeue_zc_elem_finish to complete the + * dequeue operation. + * + * @param r + * A pointer to the ring structure. + * @param esize + * The size of ring element, in bytes. It must be a multiple of 4. + * This must be the same value used while creating the ring. Otherwise + * the results are undefined. + * @param n + * The number of objects to dequeue from the ring. + * @param zcd + * Structure containing the pointers and length of the space + * reserved on the ring storage. + * @param available + * If non-NULL, returns the number of remaining ring entries after the + * dequeue has finished. + * @return + * The number of objects that can be dequeued, either 0 or n. + */ +__rte_experimental +static __rte_always_inline unsigned int +rte_ring_dequeue_zc_burst_elem_start(struct rte_ring *r, unsigned int esize, + unsigned int n, struct rte_ring_zc_data *zcd, unsigned int *available) +{ + return __rte_ring_do_dequeue_zc_elem_start(r, esize, n, + RTE_RING_QUEUE_VARIABLE, zcd, available); +} + +/** + * Start to dequeue several pointers to objects from the ring. + * Note that no actual pointers are removed from the queue by this function. + * User has to copy pointers to objects from the queue using the + * returned pointers. + * User should call rte_ring_dequeue_zc_finish to complete the + * dequeue operation. + * + * @param r + * A pointer to the ring structure. + * @param n + * The number of objects to remove from the ring. + * @param zcd + * Structure containing the pointers and length of the space + * reserved on the ring storage. + * @param available + * If non-NULL, returns the number of remaining ring entries after the + * dequeue has finished. + * @return + * The number of objects that can be dequeued, either 0 or n. + */ +__rte_experimental +static __rte_always_inline unsigned int +rte_ring_dequeue_zc_burst_start(struct rte_ring *r, unsigned int n, + struct rte_ring_zc_data *zcd, unsigned int *available) +{ + return rte_ring_dequeue_zc_burst_elem_start(r, sizeof(uintptr_t), n, + zcd, available); +} + +/** + * Complete dequeuing several objects from the ring. + * Note that number of objects to dequeued should not exceed previous + * dequeue_start return value. + * + * @param r + * A pointer to the ring structure. + * @param n + * The number of objects to remove from the ring. + */ +__rte_experimental +static __rte_always_inline void +rte_ring_dequeue_zc_elem_finish(struct rte_ring *r, unsigned int n) +{ + uint32_t tail; + + switch (r->cons.sync_type) { + case RTE_RING_SYNC_ST: + n = __rte_ring_st_get_tail(&r->cons, &tail, n); + __rte_ring_st_set_head_tail(&r->cons, tail, n, 0); + break; + case RTE_RING_SYNC_MT_HTS: + n = __rte_ring_hts_get_tail(&r->hts_cons, &tail, n); + __rte_ring_hts_set_head_tail(&r->hts_cons, tail, n, 0); + break; + case RTE_RING_SYNC_MT: + case RTE_RING_SYNC_MT_RTS: + default: + /* unsupported mode, shouldn't be here */ + RTE_ASSERT(0); + } +} + +/** + * Complete dequeuing several objects from the ring. + * Note that number of objects to dequeued should not exceed previous + * dequeue_start return value. + * + * @param r + * A pointer to the ring structure. + * @param n + * The number of objects to remove from the ring. + */ +__rte_experimental +static __rte_always_inline void +rte_ring_dequeue_zc_finish(struct rte_ring *r, unsigned int n) +{ + rte_ring_dequeue_elem_finish(r, n); +} + +#ifdef __cplusplus +} +#endif + +#endif /* _RTE_RING_PEEK_ZC_H_ */