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467 lines
14 KiB
467 lines
14 KiB
/*
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* Copyright 2009-2013 Samy Al Bahra.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef _CK_RING_H
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#define _CK_RING_H
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#include <ck_cc.h>
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#include <ck_md.h>
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#include <ck_pr.h>
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#include <stdbool.h>
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#include <string.h>
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/*
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* Concurrent ring buffer.
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*/
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#define CK_RING(type, name) \
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struct ck_ring_##name { \
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unsigned int c_head; \
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char pad[CK_MD_CACHELINE - sizeof(unsigned int)]; \
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unsigned int p_tail; \
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char _pad[CK_MD_CACHELINE - sizeof(unsigned int)]; \
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unsigned int size; \
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unsigned int mask; \
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struct type *ring; \
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}; \
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CK_CC_INLINE static void \
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ck_ring_init_##name(struct ck_ring_##name *ring, \
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struct type *buffer, \
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unsigned int size) \
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{ \
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\
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ring->size = size; \
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ring->mask = size - 1; \
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ring->p_tail = 0; \
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ring->c_head = 0; \
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ring->ring = buffer; \
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return; \
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} \
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CK_CC_INLINE static unsigned int \
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ck_ring_size_##name(struct ck_ring_##name *ring) \
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{ \
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unsigned int c, p; \
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\
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c = ck_pr_load_uint(&ring->c_head); \
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p = ck_pr_load_uint(&ring->p_tail); \
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return (p - c) & ring->mask; \
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} \
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CK_CC_INLINE static unsigned int \
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ck_ring_capacity_##name(struct ck_ring_##name *ring) \
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{ \
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\
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return ring->size; \
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} \
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CK_CC_INLINE static bool \
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ck_ring_enqueue_spsc_size_##name(struct ck_ring_##name *ring, \
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struct type *entry, \
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unsigned int *size) \
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{ \
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unsigned int consumer, producer, delta; \
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unsigned int mask = ring->mask; \
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\
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consumer = ck_pr_load_uint(&ring->c_head); \
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producer = ring->p_tail; \
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delta = producer + 1; \
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*size = (producer - consumer) & mask; \
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\
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if ((delta & mask) == (consumer & mask)) \
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return false; \
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\
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ring->ring[producer & mask] = *entry; \
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ck_pr_fence_store(); \
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ck_pr_store_uint(&ring->p_tail, delta); \
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return true; \
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} \
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CK_CC_INLINE static bool \
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ck_ring_enqueue_spsc_##name(struct ck_ring_##name *ring, \
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struct type *entry) \
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{ \
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unsigned int consumer, producer, delta; \
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unsigned int mask = ring->mask; \
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\
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consumer = ck_pr_load_uint(&ring->c_head); \
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producer = ring->p_tail; \
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delta = producer + 1; \
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\
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if ((delta & mask) == (consumer & mask)) \
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return false; \
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\
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ring->ring[producer & mask] = *entry; \
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ck_pr_fence_store(); \
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ck_pr_store_uint(&ring->p_tail, delta); \
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return true; \
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} \
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CK_CC_INLINE static bool \
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ck_ring_dequeue_spsc_##name(struct ck_ring_##name *ring, \
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struct type *data) \
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{ \
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unsigned int consumer, producer; \
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unsigned int mask = ring->mask; \
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\
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consumer = ring->c_head; \
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producer = ck_pr_load_uint(&ring->p_tail); \
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\
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if (consumer == producer) \
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return false; \
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\
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ck_pr_fence_load(); \
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*data = ring->ring[consumer & mask]; \
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ck_pr_fence_store(); \
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ck_pr_store_uint(&ring->c_head, consumer + 1); \
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\
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return true; \
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} \
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CK_CC_INLINE static bool \
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ck_ring_enqueue_spmc_size_##name(struct ck_ring_##name *ring, \
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void *entry, unsigned int *size) \
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{ \
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\
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return ck_ring_enqueue_spsc_size_##name(ring, entry, size); \
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} \
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CK_CC_INLINE static bool \
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ck_ring_enqueue_spmc_##name(struct ck_ring_##name *ring, void *entry) \
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{ \
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\
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return ck_ring_enqueue_spsc_##name(ring, entry); \
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} \
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CK_CC_INLINE static bool \
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ck_ring_trydequeue_spmc_##name(struct ck_ring_##name *ring, \
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struct type *data) \
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{ \
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unsigned int consumer, producer; \
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unsigned int mask = ring->mask; \
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\
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consumer = ck_pr_load_uint(&ring->c_head); \
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ck_pr_fence_load(); \
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producer = ck_pr_load_uint(&ring->p_tail); \
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\
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if (consumer == producer) \
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return false; \
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\
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ck_pr_fence_load(); \
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*data = ring->ring[consumer & mask]; \
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ck_pr_fence_memory(); \
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return ck_pr_cas_uint(&ring->c_head, \
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consumer, \
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consumer + 1); \
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} \
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CK_CC_INLINE static bool \
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ck_ring_dequeue_spmc_##name(struct ck_ring_##name *ring, \
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struct type *data) \
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{ \
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unsigned int consumer, producer; \
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unsigned int mask = ring->mask; \
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\
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consumer = ck_pr_load_uint(&ring->c_head); \
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do { \
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ck_pr_fence_load(); \
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producer = ck_pr_load_uint(&ring->p_tail); \
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\
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if (consumer == producer) \
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return false; \
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\
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ck_pr_fence_load(); \
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*data = ring->ring[consumer & mask]; \
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ck_pr_fence_memory(); \
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} while (ck_pr_cas_uint_value(&ring->c_head, \
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consumer, \
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consumer + 1, \
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&consumer) == false); \
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\
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return true; \
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}
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#define CK_RING_INSTANCE(name) \
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struct ck_ring_##name
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#define CK_RING_INIT(name, object, buffer, size) \
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ck_ring_init_##name(object, buffer, size)
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#define CK_RING_SIZE(name, object) \
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ck_ring_size_##name(object)
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#define CK_RING_CAPACITY(name, object) \
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ck_ring_capacity_##name(object)
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#define CK_RING_ENQUEUE_SPSC_SIZE(name, object, value, s) \
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ck_ring_enqueue_spsc_size_##name(object, value, s)
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#define CK_RING_ENQUEUE_SPSC(name, object, value) \
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ck_ring_enqueue_spsc_##name(object, value)
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#define CK_RING_DEQUEUE_SPSC(name, object, value) \
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ck_ring_dequeue_spsc_##name(object, value)
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#define CK_RING_DEQUEUE_SPMC(name, object, value) \
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ck_ring_dequeue_spmc_##name(object, value)
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#define CK_RING_TRYDEQUEUE_SPMC(name, object, value) \
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ck_ring_trydequeue_spmc_##name(object, value)
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#define CK_RING_ENQUEUE_SPMC_SIZE(name, object, value, s) \
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ck_ring_enqueue_spmc_size_##name(object, value, s)
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#define CK_RING_ENQUEUE_SPMC(name, object, value) \
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ck_ring_enqueue_spmc_##name(object, value)
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struct ck_ring {
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unsigned int c_head;
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char pad[CK_MD_CACHELINE - sizeof(unsigned int)];
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unsigned int p_tail;
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char _pad[CK_MD_CACHELINE - sizeof(unsigned int)];
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unsigned int size;
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unsigned int mask;
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void **ring;
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};
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typedef struct ck_ring ck_ring_t;
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/*
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* Single consumer and single producer ring buffer enqueue (producer).
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*/
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CK_CC_INLINE static unsigned int
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ck_ring_size(struct ck_ring *ring)
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{
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unsigned int c, p;
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c = ck_pr_load_uint(&ring->c_head);
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p = ck_pr_load_uint(&ring->p_tail);
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return (p - c) & ring->mask;
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}
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CK_CC_INLINE static unsigned int
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ck_ring_capacity(struct ck_ring *ring)
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{
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return ring->size;
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}
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/*
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* Atomically enqueues the specified entry. Returns true on success, returns
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* false if the ck_ring is full. This operation only support one active
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* invocation at a time and works in the presence of a concurrent invocation
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* of ck_ring_dequeue_spsc.
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*
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* This variant of ck_ring_enqueue_spsc returns the snapshot of queue length
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* with respect to the linearization point. This can be used to extract ring
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* size without incurring additional cacheline invalidation overhead from the
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* writer.
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*/
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CK_CC_INLINE static bool
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ck_ring_enqueue_spsc_size(struct ck_ring *ring,
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void *entry,
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unsigned int *size)
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{
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unsigned int consumer, producer, delta;
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unsigned int mask = ring->mask;
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consumer = ck_pr_load_uint(&ring->c_head);
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producer = ring->p_tail;
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delta = producer + 1;
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*size = (producer - consumer) & mask;
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if ((delta & mask) == (consumer & mask))
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return false;
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ring->ring[producer & mask] = entry;
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/*
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* Make sure to update slot value before indicating
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* that the slot is available for consumption.
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*/
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ck_pr_fence_store();
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ck_pr_store_uint(&ring->p_tail, delta);
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return true;
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}
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/*
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* Atomically enqueues the specified entry. Returns true on success, returns
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* false if the ck_ring is full. This operation only support one active
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* invocation at a time and works in the presence of a concurrent invocation
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* of ck_ring_dequeue_spsc.
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*/
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CK_CC_INLINE static bool
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ck_ring_enqueue_spsc(struct ck_ring *ring, void *entry)
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{
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unsigned int consumer, producer, delta;
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unsigned int mask = ring->mask;
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consumer = ck_pr_load_uint(&ring->c_head);
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producer = ring->p_tail;
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delta = producer + 1;
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if ((delta & mask) == (consumer & mask))
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return false;
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ring->ring[producer & mask] = entry;
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/*
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* Make sure to update slot value before indicating
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* that the slot is available for consumption.
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*/
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ck_pr_fence_store();
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ck_pr_store_uint(&ring->p_tail, delta);
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return true;
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}
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/*
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* Single consumer and single producer ring buffer dequeue (consumer).
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*/
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CK_CC_INLINE static bool
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ck_ring_dequeue_spsc(struct ck_ring *ring, void *data)
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{
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unsigned int consumer, producer;
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unsigned int mask = ring->mask;
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consumer = ring->c_head;
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producer = ck_pr_load_uint(&ring->p_tail);
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if (consumer == producer)
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return false;
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/*
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* Make sure to serialize with respect to our snapshot
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* of the producer counter.
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*/
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ck_pr_fence_load();
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/*
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* This is used to work-around aliasing issues (C
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* lacks a generic pointer to pointer despite it
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* being a reality on POSIX). This interface is
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* troublesome on platforms where sizeof(void *)
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* is not guaranteed to be sizeof(T *).
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*/
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ck_pr_store_ptr(data, ring->ring[consumer & mask]);
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ck_pr_fence_store();
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ck_pr_store_uint(&ring->c_head, consumer + 1);
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return true;
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}
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/*
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* Atomically enqueues the specified entry. Returns true on success, returns
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* false if the ck_ring is full. This operation only support one active
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* invocation at a time and works in the presence of up to UINT_MAX concurrent
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* invocations of ck_ring_dequeue_spmc.
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*
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* This variant of ck_ring_enqueue_spmc returns the snapshot of queue length
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* with respect to the linearization point. This can be used to extract ring
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* size without incurring additional cacheline invalidation overhead from the
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* writer.
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*/
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CK_CC_INLINE static bool
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ck_ring_enqueue_spmc_size(struct ck_ring *ring,
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void *entry,
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unsigned int *size)
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{
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return ck_ring_enqueue_spsc_size(ring, entry, size);
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}
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/*
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* Atomically enqueues the specified entry. Returns true on success, returns
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* false if the ck_ring is full. This operation only support one active
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* invocation at a time and works in the presence of up to UINT_MAX concurrent
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* invocations of ck_ring_dequeue_spmc.
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*/
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CK_CC_INLINE static bool
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ck_ring_enqueue_spmc(struct ck_ring *ring, void *entry)
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{
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return ck_ring_enqueue_spsc(ring, entry);
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}
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CK_CC_INLINE static bool
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ck_ring_trydequeue_spmc(struct ck_ring *ring, void *data)
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{
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unsigned int consumer, producer;
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unsigned int mask = ring->mask;
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consumer = ck_pr_load_uint(&ring->c_head);
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ck_pr_fence_load();
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producer = ck_pr_load_uint(&ring->p_tail);
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if (consumer == producer)
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return false;
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ck_pr_fence_load();
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ck_pr_store_ptr(data, ring->ring[consumer & mask]);
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ck_pr_fence_memory();
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return ck_pr_cas_uint(&ring->c_head, consumer, consumer + 1);
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}
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CK_CC_INLINE static bool
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ck_ring_dequeue_spmc(struct ck_ring *ring, void *data)
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{
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unsigned int consumer, producer;
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unsigned int mask = ring->mask;
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void *r;
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consumer = ck_pr_load_uint(&ring->c_head);
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do {
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/*
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* Producer counter must represent state relative to
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* our latest consumer snapshot.
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*/
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ck_pr_fence_load();
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producer = ck_pr_load_uint(&ring->p_tail);
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if (consumer == producer)
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return false;
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ck_pr_fence_load();
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/*
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* Both LLVM and GCC have generated code which completely
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* ignores the semantics of the r load, despite it being
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* sandwiched between compiler barriers. We use an atomic
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* volatile load to force volatile semantics while allowing
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* for r itself to remain aliased across the loop.
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*/
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r = ck_pr_load_ptr(&ring->ring[consumer & mask]);
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/* Serialize load with respect to head update. */
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ck_pr_fence_memory();
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} while (ck_pr_cas_uint_value(&ring->c_head,
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consumer,
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consumer + 1,
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&consumer) == false);
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/*
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* Force spillage while avoiding aliasing issues that aren't
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* a problem on POSIX.
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*/
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ck_pr_store_ptr(data, r);
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return true;
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}
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CK_CC_INLINE static void
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ck_ring_init(struct ck_ring *ring, void *buffer, unsigned int size)
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{
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memset(buffer, 0, sizeof(void *) * size);
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ring->size = size;
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ring->mask = size - 1;
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ring->p_tail = 0;
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ring->c_head = 0;
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ring->ring = buffer;
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return;
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}
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#endif /* _CK_RING_H */
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