96 строки
2.9 KiB
C
96 строки
2.9 KiB
C
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/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil -*- */
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/*
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* Copyright (c) 2014-2016 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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* $COPYRIGHT$
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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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#include "wait_sync.h"
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static opal_mutex_t wait_sync_lock = OPAL_MUTEX_STATIC_INIT;
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static ompi_wait_sync_t* wait_sync_list = NULL;
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#define WAIT_SYNC_PASS_OWNERSHIP(who) \
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do { \
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pthread_mutex_lock( &(who)->lock); \
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pthread_cond_signal( &(who)->condition ); \
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pthread_mutex_unlock( &(who)->lock); \
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} while(0)
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int sync_wait_st(ompi_wait_sync_t *sync)
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{
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while(sync->count > 0) {
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opal_progress();
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}
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return OPAL_SUCCESS;
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}
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int sync_wait_mt(ompi_wait_sync_t *sync)
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{
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if(sync->count <= 0)
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return OPAL_SUCCESS;
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/* lock so nobody can signal us during the list updating */
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pthread_mutex_lock(&sync->lock);
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/* Insert sync to the list */
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OPAL_THREAD_LOCK(&wait_sync_lock);
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if( NULL == wait_sync_list ) {
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sync->next = sync->prev = sync;
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wait_sync_list = sync;
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} else {
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sync->prev = wait_sync_list->prev;
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sync->prev->next = sync;
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sync->next = wait_sync_list;
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wait_sync_list->prev = sync;
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}
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OPAL_THREAD_UNLOCK(&wait_sync_lock);
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/**
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* If we are not responsible for progresing, let's go silent until something worth noticing happen:
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* - this thread has been promoted to take care of the progress
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* - our sync has been triggered.
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*/
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if( sync != wait_sync_list ) {
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pthread_cond_wait(&sync->condition, &sync->lock);
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/**
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* At this point either the sync was completed in which case we should remove it from the wait
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* list, or/and I was promoted as the progress manager.
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*/
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if( sync->count <= 0 ) { /* Completed? */
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pthread_mutex_unlock(&sync->lock);
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goto i_am_done;
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}
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/* promoted ! */
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assert(sync == wait_sync_list);
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}
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pthread_mutex_unlock(&sync->lock);
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while(sync->count > 0) { /* progress till completion */
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opal_progress(); /* don't progress with the sync lock locked or you'll deadlock */
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}
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assert(sync == wait_sync_list);
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i_am_done:
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/* My sync is now complete. Trim the list: remove self, wake next */
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OPAL_THREAD_LOCK(&wait_sync_lock);
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sync->prev->next = sync->next;
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sync->next->prev = sync->prev;
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/* In case I am the progress manager, pass the duties on */
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if( sync == wait_sync_list ) {
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wait_sync_list = (sync == sync->next) ? NULL : sync->next;
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if( NULL != wait_sync_list )
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WAIT_SYNC_PASS_OWNERSHIP(wait_sync_list);
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}
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OPAL_THREAD_UNLOCK(&wait_sync_lock);
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return OPAL_SUCCESS;
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}
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