366 строки
10 KiB
C
366 строки
10 KiB
C
/*
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* Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
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* University Research and Technology
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* Corporation. All rights reserved.
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* Copyright (c) 2004-2006 The University of Tennessee and The University
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* of Tennessee Research Foundation. All rights
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* reserved.
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* Copyright (c) 2004-2005 High Performance Computing Center Stuttgart,
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* University of Stuttgart. All rights reserved.
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* Copyright (c) 2004-2005 The Regents of the University of California.
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* All rights reserved.
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* $COPYRIGHT$
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*
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* Additional copyrights may follow
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*
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* $HEADER$
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*/
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#ifndef _OMPI_CIRCULAR_BUFFER_FIFO
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#define _OMPI_CIRCULAR_BUFFER_FIFO
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#include "ompi/constants.h"
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#include "opal/sys/cache.h"
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#include "opal/sys/atomic.h"
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#include "ompi/mca/mpool/mpool.h"
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#include "opal/util/pow2.h"
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/** @file
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*
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* This defines a set of functions to create, and manipulate a FIFO
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* set up in a circular buffer. FIFO elements are assumed to be
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* pointers. Pointers are written to the head, and read from the
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* tail. For thread safety, a spin lock is provided in the
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* ompi_cb_fifo_ctl_t structure, but it's use must be managed by
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* the calling routines - this is not by these set of routines.
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* Queues are addressed relative to an offset from the base of
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* a memory pool, in this way, different processes with different
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* base addresses can access these queue at the same time.
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*/
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/* error code */
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#define OMPI_CB_ERROR -1
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#define OMPI_CB_FREE (void *)-2
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#define OMPI_CB_RESERVED (void *)-3
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#define OMPI_CB_NULL (void *)-4
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/*
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* Structure used to keep track of the fifo status
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*/
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struct ompi_cb_fifo_ctl_t {
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/* spin-lock for access control */
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opal_atomic_lock_t lock;
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/* current queue index */
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volatile int fifo_index;
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/* number of entries that have been used, but not invalidated. used
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* for lazy resource reclamation */
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int num_to_clear;
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};
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typedef struct ompi_cb_fifo_ctl_t ompi_cb_fifo_ctl_t;
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/* data structure used to describe the fifo */
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struct ompi_cb_fifo_t {
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/* head of queue - where next entry will be written (sender address)*/
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ompi_cb_fifo_ctl_t *head;
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/* tail of queue - next element to read (receiver address) */
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ompi_cb_fifo_ctl_t *tail;
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/* head of queue - where next entry will be written (receiver address) */
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ompi_cb_fifo_ctl_t *recv_head;
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/* circular buffer array (sender address) */
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volatile void **queue;
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/* circular buffer array (receiver address) */
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volatile void **recv_queue;
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/* frequency of lazy free */
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int lazy_free_frequency;
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/* mask - to handle wrap around */
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unsigned int mask;
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};
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typedef struct ompi_cb_fifo_t ompi_cb_fifo_t;
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/**
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* Return the fifo size
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*
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* @param fifo Pointer to data structure defining this fifo (IN)
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*
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* @returncode fifo size
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*
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*/
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static inline int ompi_cb_fifo_size(ompi_cb_fifo_t *fifo) {
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return fifo->mask + 1;
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}
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/**
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* Initialize a fifo
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*
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* @param size_of_fifo Length of fifo array (IN)
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*
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* @param fifo_memory_locality_index Locality index to apply to
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* the fifo array. Not currently
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* in use (IN)
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*
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* @param tail_memory_locality_index Locality index to apply to the
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* head control structure. Not
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* currently in use (IN)
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*
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* @param tail_memory_locality_index Locality index to apply to the
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* tail control structure. Not
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* currently in use (IN)
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*
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* @param fifo Pointer to data structure defining this fifo (IN)
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*
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* @param memory_allocator Pointer to the memory allocator to use
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* to allocate memory for this fifo. (IN)
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*
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* @returncode Error code
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*
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*/
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static inline int ompi_cb_fifo_init(int size_of_fifo,
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int lazy_free_freq, int fifo_memory_locality_index,
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int head_memory_locality_index, int tail_memory_locality_index,
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ompi_cb_fifo_t *fifo, ptrdiff_t offset,
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mca_mpool_base_module_t *memory_allocator)
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{
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int i, size;
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char *buf;
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/* verify that size is power of 2, and greater that 0 - if not,
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* round up */
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if(size_of_fifo <= 0) {
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return OMPI_ERROR;
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}
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/* set fifo size */
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size = opal_round_up_to_nearest_pow2(size_of_fifo);
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/* set lazy free frequence */
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if((lazy_free_freq <= 0) || (lazy_free_freq > size)) {
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return OMPI_ERROR;
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}
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fifo->lazy_free_frequency = lazy_free_freq;
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/* this will be used to mask off the higher order bits,
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* and use the & operator for the wrap-around */
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fifo->mask = (size - 1);
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/* allocate fifo array */
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buf = memory_allocator->mpool_alloc(memory_allocator,
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sizeof(void *) * size + 2*CACHE_LINE_SIZE, CACHE_LINE_SIZE, 0,
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NULL);
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if (NULL == buf) {
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return OMPI_ERR_OUT_OF_RESOURCE;
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}
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fifo->queue = (volatile void**)(buf + 2*CACHE_LINE_SIZE);
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/* buffer address in a receiver address space */
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fifo->recv_queue = (volatile void**)((char*)fifo->queue - offset);
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/* initialize the queue entries */
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for (i = 0; i < size; i++) {
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fifo->queue[i] = OMPI_CB_FREE;
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}
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fifo->head = (ompi_cb_fifo_ctl_t*)buf;
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/* head address in a receiver address space */
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fifo->recv_head = (ompi_cb_fifo_ctl_t*)((char*)fifo->head - offset);
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fifo->tail = (ompi_cb_fifo_ctl_t*)(buf + CACHE_LINE_SIZE);
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/* initialize the head structure */
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opal_atomic_unlock(&(fifo->head->lock));
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fifo->head->fifo_index=0;
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fifo->head->num_to_clear=0;
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/* initialize the head structure */
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opal_atomic_unlock(&(fifo->tail->lock));
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fifo->tail->fifo_index=0;
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fifo->tail->num_to_clear=0;
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/* recalculate tail address in a receiver address space */
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fifo->tail = (ompi_cb_fifo_ctl_t*)((char*)fifo->tail - offset);
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/* return */
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return OMPI_SUCCESS;
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}
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/**
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* function to cleanup the fifo
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*
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* @param fifo Pointer to data structure defining this fifo (IN)
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*
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* @param memory_allocator Pointer to the memory allocator to use
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* to allocate memory for this fifo. (IN)
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*
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*/
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static inline int ompi_cb_fifo_free(ompi_cb_fifo_t *fifo,
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mca_mpool_base_module_t *memory_allocator)
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{
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char *ptr;
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/* make sure null fifo is not passed in */
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if(NULL == fifo) {
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return OMPI_ERROR;
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}
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/* free fifo array */
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if(OMPI_CB_NULL != fifo->head){
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ptr=(char *)(fifo->head);
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memory_allocator->mpool_free(memory_allocator, ptr, NULL);
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fifo->queue = (volatile void**)OMPI_CB_NULL;
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}
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return OMPI_SUCCESS;
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}
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/**
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* Write pointer to the specified slot
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*
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* @param slot Slot index (IN)
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*
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* @param data Pointer value to write in specified slot (IN)
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*
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* @param fifo Pointer to data structure defining this fifo (IN)
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*
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* @returncode Slot index to which data is written
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*
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*/
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static inline int ompi_cb_fifo_write_to_slot(int slot, void* data,
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ompi_cb_fifo_t *fifo)
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{
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volatile void **ptr;
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/* make sure that this slot is already reserved */
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ptr=fifo->queue;
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if (ptr[slot] == OMPI_CB_RESERVED ) {
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opal_atomic_rmb();
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ptr[slot] = data;
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opal_atomic_wmb();
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return slot;
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}
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return OMPI_CB_ERROR;
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}
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/**
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* Try to write pointer to the head of the queue
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*
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* @param data Pointer value to write in specified slot (IN)
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*
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* @param fifo Pointer to data structure defining this fifo (IN)
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*
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* @returncode Slot index to which data is written
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*
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*/
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static inline int ompi_cb_fifo_write_to_head(void *data, ompi_cb_fifo_t *fifo)
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{
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volatile void **ptr;
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ompi_cb_fifo_ctl_t *h_ptr;
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int index;
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h_ptr=fifo->head;
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ptr=fifo->queue;
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index = h_ptr->fifo_index;
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/* make sure the head is pointing at a free element */
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if (ptr[index] == OMPI_CB_FREE) {
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opal_atomic_rmb();
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ptr[index] = data;
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opal_atomic_wmb();
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h_ptr->fifo_index = (index + 1) & fifo->mask;
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return index;
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}
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/* return */
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return OMPI_CB_ERROR;
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}
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/**
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* Reserve slot in the fifo array
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*
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* @param fifo Pointer to data structure defining this fifo (IN)
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*
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* @returncode Slot index to which data is written
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*
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* @returncode OMPI_CB_ERROR failed to allocate index
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*
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*/
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static inline int ompi_cb_fifo_get_slot(ompi_cb_fifo_t *fifo)
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{
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return ompi_cb_fifo_write_to_head(OMPI_CB_RESERVED, fifo);
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}
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/**
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* Try to read pointer from the tail of the queue
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*
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* @param data Pointer to where data was be written (OUT)
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*
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* @param fifo Pointer to data structure defining this fifo (IN)
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*
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* @param flush_entries_read force the lazy free to happen (IN)
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*
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* @param queue_empty checks to see if the fifo is empty, but only if
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* flush_entries_read is set (OUT)
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*
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* @returncode Slot index to which data is written
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*
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*/
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static inline void *ompi_cb_fifo_read_from_tail(
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ompi_cb_fifo_t *fifo,
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bool flush_entries_read, bool *queue_empty)
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{
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int index, i;
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volatile void **q_ptr;
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ompi_cb_fifo_ctl_t *t_ptr;
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void *read_from_tail;
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*queue_empty=false;
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t_ptr=fifo->tail;
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q_ptr=fifo->recv_queue;
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index = t_ptr->fifo_index;
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read_from_tail = (void *)q_ptr[index];
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opal_atomic_rmb();
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/* check to see that the data is valid */
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if ((read_from_tail == OMPI_CB_FREE) ||
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(read_from_tail == OMPI_CB_RESERVED)) {
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return (void*)OMPI_CB_FREE;
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}
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/* increment counter for later lazy free */
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t_ptr->num_to_clear++;
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t_ptr->fifo_index = (index + 1) & fifo->mask;
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/* check to see if time to do a lazy free of queue slots */
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if ( (t_ptr->num_to_clear == fifo->lazy_free_frequency) ||
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flush_entries_read ) {
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ompi_cb_fifo_ctl_t *h_ptr = fifo->recv_head;
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index = (index - t_ptr->num_to_clear + 1) & fifo->mask;
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for (i = 0; i < t_ptr->num_to_clear; i++) {
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q_ptr[index] = OMPI_CB_FREE;
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index = (index + 1) & fifo->mask;
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}
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opal_atomic_wmb();
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t_ptr->num_to_clear = 0;
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/* check to see if queue is empty */
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if( flush_entries_read &&
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(t_ptr->fifo_index == h_ptr->fifo_index) ) {
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*queue_empty=true;
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}
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}
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return read_from_tail;
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}
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#endif /* !_OMPI_CIRCULAR_BUFFER_FIFO */
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