1
0
Fork 0
mirror of https://git.rwth-aachen.de/acs/public/villas/node/ synced 2025-03-30 00:00:11 +01:00
VILLASnode/include/villas/queue.h

87 lines
No EOL
3 KiB
C

/** Lock-free Multiple-Producer Multiple-consumer (MPMC) queue.
*
* Based on Dmitry Vyukov#s Bounded MPMC queue:
* http://www.1024cores.net/home/lock-free-algorithms/queues/bounded-mpmc-queue
*
* @author Steffen Vogel <post@steffenvogel.de>
* @copyright 2016 Steffen Vogel
* @license BSD 2-Clause License
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modiffication, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _MPMC_QUEUE_H_
#define _MPMC_QUEUE_H_
#include <stdint.h>
#include <stdatomic.h>
#include "memory.h"
#define CACHELINE_SIZE 64
typedef char cacheline_pad_t[CACHELINE_SIZE];
struct mpmc_queue {
cacheline_pad_t _pad0; /**< Shared area: all threads read */
struct memtype const * mem;
size_t buffer_mask;
struct mpmc_queue_cell {
atomic_size_t sequence;
void *data;
} *buffer;
cacheline_pad_t _pad1; /**> Producer area: only producers read & write */
atomic_size_t tail; /**> Queue tail pointer */
cacheline_pad_t _pad2; /**> Consumer area: only consumers read & write */
atomic_size_t head; /**> Queue head pointer */
cacheline_pad_t _pad3; /**> @todo Why needed? */
};
/** Initialize MPMC queue */
int mpmc_queue_init(struct mpmc_queue *q, size_t size, const struct memtype *mem);
/** Desroy MPMC queue and release memory */
int mpmc_queue_destroy(struct mpmc_queue *q);
/** Return estimation of current queue usage.
*
* Note: This is only an estimation and not accurate as long other
* threads are performing operations.
*/
size_t mpmc_queue_available(struct mpmc_queue *q);
int mpmc_queue_push(struct mpmc_queue *q, void *ptr);
int mpmc_queue_pull(struct mpmc_queue *q, void **ptr);
int mpmc_queue_push_many(struct mpmc_queue *q, void *ptr[], size_t cnt);
int mpmc_queue_pull_many(struct mpmc_queue *q, void *ptr[], size_t cnt);
#endif /* _MPMC_QUEUE_H_ */