| /* |
| * kmp_taskdeps.cpp |
| * $Revision: 42539 $ |
| * $Date: 2013-07-17 11:20:01 -0500 (Wed, 17 Jul 2013) $ |
| */ |
| |
| |
| //===----------------------------------------------------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is dual licensed under the MIT and the University of Illinois Open |
| // Source Licenses. See LICENSE.txt for details. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| |
| //#define KMP_SUPPORT_GRAPH_OUTPUT 1 |
| |
| #include "kmp.h" |
| #include "kmp_io.h" |
| #include "kmp_wait_release.h" |
| |
| #if OMP_40_ENABLED |
| |
| //TODO: Improve memory allocation? keep a list of pre-allocated structures? allocate in blocks? re-use list finished list entries? |
| //TODO: don't use atomic ref counters for stack-allocated nodes. |
| //TODO: find an alternate to atomic refs for heap-allocated nodes? |
| //TODO: Finish graph output support |
| //TODO: kmp_lock_t seems a tad to big (and heavy weight) for this. Check other runtime locks |
| //TODO: Any ITT support needed? |
| |
| #ifdef KMP_SUPPORT_GRAPH_OUTPUT |
| static kmp_int32 kmp_node_id_seed = 0; |
| #endif |
| |
| static void |
| __kmp_init_node ( kmp_depnode_t *node ) |
| { |
| node->dn.task = NULL; // set to null initially, it will point to the right task once dependences have been processed |
| node->dn.successors = NULL; |
| __kmp_init_lock(&node->dn.lock); |
| node->dn.nrefs = 1; // init creates the first reference to the node |
| #ifdef KMP_SUPPORT_GRAPH_OUTPUT |
| node->dn.id = KMP_TEST_THEN_INC32(&kmp_node_id_seed); |
| #endif |
| } |
| |
| static inline kmp_depnode_t * |
| __kmp_node_ref ( kmp_depnode_t *node ) |
| { |
| KMP_TEST_THEN_INC32(&node->dn.nrefs); |
| return node; |
| } |
| |
| static inline void |
| __kmp_node_deref ( kmp_info_t *thread, kmp_depnode_t *node ) |
| { |
| if (!node) return; |
| |
| kmp_int32 n = KMP_TEST_THEN_DEC32(&node->dn.nrefs) - 1; |
| if ( n == 0 ) { |
| KMP_ASSERT(node->dn.nrefs == 0); |
| #if USE_FAST_MEMORY |
| __kmp_fast_free(thread,node); |
| #else |
| __kmp_thread_free(thread,node); |
| #endif |
| } |
| } |
| |
| #define KMP_ACQUIRE_DEPNODE(gtid,n) __kmp_acquire_lock(&(n)->dn.lock,(gtid)) |
| #define KMP_RELEASE_DEPNODE(gtid,n) __kmp_release_lock(&(n)->dn.lock,(gtid)) |
| |
| static void |
| __kmp_depnode_list_free ( kmp_info_t *thread, kmp_depnode_list *list ); |
| |
| static const kmp_int32 kmp_dephash_log2 = 6; |
| static const kmp_int32 kmp_dephash_size = (1 << kmp_dephash_log2); |
| |
| static inline kmp_int32 |
| __kmp_dephash_hash ( kmp_intptr_t addr ) |
| { |
| //TODO alternate to try: set = (((Addr64)(addrUsefulBits * 9.618)) % m_num_sets ); |
| return ((addr >> kmp_dephash_log2) ^ addr) % kmp_dephash_size; |
| } |
| |
| static kmp_dephash_t * |
| __kmp_dephash_create ( kmp_info_t *thread ) |
| { |
| kmp_dephash_t *h; |
| |
| kmp_int32 size = kmp_dephash_size * sizeof(kmp_dephash_entry_t) + sizeof(kmp_dephash_t); |
| |
| #if USE_FAST_MEMORY |
| h = (kmp_dephash_t *) __kmp_fast_allocate( thread, size ); |
| #else |
| h = (kmp_dephash_t *) __kmp_thread_malloc( thread, size ); |
| #endif |
| |
| #ifdef KMP_DEBUG |
| h->nelements = 0; |
| #endif |
| h->buckets = (kmp_dephash_entry **)(h+1); |
| |
| for ( kmp_int32 i = 0; i < kmp_dephash_size; i++ ) |
| h->buckets[i] = 0; |
| |
| return h; |
| } |
| |
| static void |
| __kmp_dephash_free ( kmp_info_t *thread, kmp_dephash_t *h ) |
| { |
| for ( kmp_int32 i=0; i < kmp_dephash_size; i++ ) { |
| if ( h->buckets[i] ) { |
| kmp_dephash_entry_t *next; |
| for ( kmp_dephash_entry_t *entry = h->buckets[i]; entry; entry = next ) { |
| next = entry->next_in_bucket; |
| __kmp_depnode_list_free(thread,entry->last_ins); |
| __kmp_node_deref(thread,entry->last_out); |
| #if USE_FAST_MEMORY |
| __kmp_fast_free(thread,entry); |
| #else |
| __kmp_thread_free(thread,entry); |
| #endif |
| } |
| } |
| } |
| #if USE_FAST_MEMORY |
| __kmp_fast_free(thread,h); |
| #else |
| __kmp_thread_free(thread,h); |
| #endif |
| } |
| |
| static kmp_dephash_entry * |
| __kmp_dephash_find ( kmp_info_t *thread, kmp_dephash_t *h, kmp_intptr_t addr ) |
| { |
| kmp_int32 bucket = __kmp_dephash_hash(addr); |
| |
| kmp_dephash_entry_t *entry; |
| for ( entry = h->buckets[bucket]; entry; entry = entry->next_in_bucket ) |
| if ( entry->addr == addr ) break; |
| |
| if ( entry == NULL ) { |
| // create entry. This is only done by one thread so no locking required |
| #if USE_FAST_MEMORY |
| entry = (kmp_dephash_entry_t *) __kmp_fast_allocate( thread, sizeof(kmp_dephash_entry_t) ); |
| #else |
| entry = (kmp_dephash_entry_t *) __kmp_thread_malloc( thread, sizeof(kmp_dephash_entry_t) ); |
| #endif |
| entry->addr = addr; |
| entry->last_out = NULL; |
| entry->last_ins = NULL; |
| entry->next_in_bucket = h->buckets[bucket]; |
| h->buckets[bucket] = entry; |
| #ifdef KMP_DEBUG |
| h->nelements++; |
| if ( entry->next_in_bucket ) h->nconflicts++; |
| #endif |
| } |
| return entry; |
| } |
| |
| static kmp_depnode_list_t * |
| __kmp_add_node ( kmp_info_t *thread, kmp_depnode_list_t *list, kmp_depnode_t *node ) |
| { |
| kmp_depnode_list_t *new_head; |
| |
| #if USE_FAST_MEMORY |
| new_head = (kmp_depnode_list_t *) __kmp_fast_allocate(thread,sizeof(kmp_depnode_list_t)); |
| #else |
| new_head = (kmp_depnode_list_t *) __kmp_thread_malloc(thread,sizeof(kmp_depnode_list_t)); |
| #endif |
| |
| new_head->node = __kmp_node_ref(node); |
| new_head->next = list; |
| |
| return new_head; |
| } |
| |
| static void |
| __kmp_depnode_list_free ( kmp_info_t *thread, kmp_depnode_list *list ) |
| { |
| kmp_depnode_list *next; |
| |
| for ( ; list ; list = next ) { |
| next = list->next; |
| |
| __kmp_node_deref(thread,list->node); |
| #if USE_FAST_MEMORY |
| __kmp_fast_free(thread,list); |
| #else |
| __kmp_thread_free(thread,list); |
| #endif |
| } |
| } |
| |
| static inline void |
| __kmp_track_dependence ( kmp_depnode_t *source, kmp_depnode_t *sink ) |
| { |
| #ifdef KMP_SUPPORT_GRAPH_OUTPUT |
| kmp_taskdata_t * task_source = KMP_TASK_TO_TASKDATA(source->dn.task); |
| kmp_taskdata_t * task_sink = KMP_TASK_TO_TASKDATA(sink->dn.task); // this can be NULL when if(0) ... |
| |
| __kmp_printf("%d(%s) -> %d(%s)\n", source->dn.id, task_source->td_ident->psource, sink->dn.id, task_sink->td_ident->psource); |
| #endif |
| } |
| |
| template< bool filter > |
| static inline kmp_int32 |
| __kmp_process_deps ( kmp_int32 gtid, kmp_depnode_t *node, kmp_dephash_t *hash, |
| bool dep_barrier,kmp_int32 ndeps, kmp_depend_info_t *dep_list) |
| { |
| KA_TRACE(30, ("__kmp_process_deps<%d>: T#%d processing %d depencies : dep_barrier = %d\n", filter, gtid, ndeps, dep_barrier ) ); |
| |
| kmp_info_t *thread = __kmp_threads[ gtid ]; |
| kmp_int32 npredecessors=0; |
| for ( kmp_int32 i = 0; i < ndeps ; i++ ) { |
| const kmp_depend_info_t * dep = &dep_list[i]; |
| |
| KMP_DEBUG_ASSERT(dep->flags.in); |
| |
| if ( filter && dep->base_addr == 0 ) continue; // skip filtered entries |
| |
| kmp_dephash_entry_t *info = __kmp_dephash_find(thread,hash,dep->base_addr); |
| kmp_depnode_t *last_out = info->last_out; |
| |
| if ( dep->flags.out && info->last_ins ) { |
| for ( kmp_depnode_list_t * p = info->last_ins; p; p = p->next ) { |
| kmp_depnode_t * indep = p->node; |
| if ( indep->dn.task ) { |
| KMP_ACQUIRE_DEPNODE(gtid,indep); |
| if ( indep->dn.task ) { |
| __kmp_track_dependence(indep,node); |
| indep->dn.successors = __kmp_add_node(thread, indep->dn.successors, node); |
| KA_TRACE(40,("__kmp_process_deps<%d>: T#%d adding dependence from %p to %p", |
| filter,gtid, KMP_TASK_TO_TASKDATA(indep->dn.task), KMP_TASK_TO_TASKDATA(node->dn.task))); |
| npredecessors++; |
| } |
| KMP_RELEASE_DEPNODE(gtid,indep); |
| } |
| } |
| |
| __kmp_depnode_list_free(thread,info->last_ins); |
| info->last_ins = NULL; |
| |
| } else if ( last_out && last_out->dn.task ) { |
| KMP_ACQUIRE_DEPNODE(gtid,last_out); |
| if ( last_out->dn.task ) { |
| __kmp_track_dependence(last_out,node); |
| last_out->dn.successors = __kmp_add_node(thread, last_out->dn.successors, node); |
| KA_TRACE(40,("__kmp_process_deps<%d>: T#%d adding dependence from %p to %p", |
| filter,gtid, KMP_TASK_TO_TASKDATA(last_out->dn.task), KMP_TASK_TO_TASKDATA(node->dn.task))); |
| |
| npredecessors++; |
| } |
| KMP_RELEASE_DEPNODE(gtid,last_out); |
| } |
| |
| if ( dep_barrier ) { |
| // if this is a sync point in the serial sequence, then the previous outputs are guaranteed to be completed after |
| // the execution of this task so the previous output nodes can be cleared. |
| __kmp_node_deref(thread,last_out); |
| info->last_out = NULL; |
| } else { |
| if ( dep->flags.out ) { |
| __kmp_node_deref(thread,last_out); |
| info->last_out = __kmp_node_ref(node); |
| } else |
| info->last_ins = __kmp_add_node(thread, info->last_ins, node); |
| } |
| |
| } |
| |
| KA_TRACE(30, ("__kmp_process_deps<%d>: T#%d found %d predecessors\n", filter, gtid, npredecessors ) ); |
| |
| return npredecessors; |
| } |
| |
| #define NO_DEP_BARRIER (false) |
| #define DEP_BARRIER (true) |
| |
| // returns true if the task has any outstanding dependence |
| static bool |
| __kmp_check_deps ( kmp_int32 gtid, kmp_depnode_t *node, kmp_task_t *task, kmp_dephash_t *hash, bool dep_barrier, |
| kmp_int32 ndeps, kmp_depend_info_t *dep_list, |
| kmp_int32 ndeps_noalias, kmp_depend_info_t *noalias_dep_list ) |
| { |
| int i; |
| |
| kmp_taskdata_t * taskdata = KMP_TASK_TO_TASKDATA(task); |
| KA_TRACE(20, ("__kmp_check_deps: T#%d checking dependencies for task %p : %d possibly aliased dependencies, %d non-aliased depedencies : dep_barrier=%d .\n", gtid, taskdata, ndeps, ndeps_noalias, dep_barrier ) ); |
| |
| // Filter deps in dep_list |
| // TODO: Different algorithm for large dep_list ( > 10 ? ) |
| for ( i = 0; i < ndeps; i ++ ) { |
| if ( dep_list[i].base_addr != 0 ) |
| for ( int j = i+1; j < ndeps; j++ ) |
| if ( dep_list[i].base_addr == dep_list[j].base_addr ) { |
| dep_list[i].flags.in |= dep_list[j].flags.in; |
| dep_list[i].flags.out |= dep_list[j].flags.out; |
| dep_list[j].base_addr = 0; // Mark j element as void |
| } |
| } |
| |
| // doesn't need to be atomic as no other thread is going to be accessing this node just yet |
| // npredecessors is set -1 to ensure that none of the releasing tasks queues this task before we have finished processing all the dependencies |
| node->dn.npredecessors = -1; |
| |
| // used to pack all npredecessors additions into a single atomic operation at the end |
| int npredecessors; |
| |
| npredecessors = __kmp_process_deps<true>(gtid, node, hash, dep_barrier, ndeps, dep_list); |
| npredecessors += __kmp_process_deps<false>(gtid, node, hash, dep_barrier, ndeps_noalias, noalias_dep_list); |
| |
| node->dn.task = task; |
| KMP_MB(); |
| |
| // Account for our initial fake value |
| npredecessors++; |
| |
| // Update predecessors and obtain current value to check if there are still any outstandig dependences (some tasks may have finished while we processed the dependences) |
| npredecessors = KMP_TEST_THEN_ADD32(&node->dn.npredecessors, npredecessors) + npredecessors; |
| |
| KA_TRACE(20, ("__kmp_check_deps: T#%d found %d predecessors for task %p \n", gtid, npredecessors, taskdata ) ); |
| |
| // beyond this point the task could be queued (and executed) by a releasing task... |
| return npredecessors > 0 ? true : false; |
| } |
| |
| void |
| __kmp_release_deps ( kmp_int32 gtid, kmp_taskdata_t *task ) |
| { |
| kmp_info_t *thread = __kmp_threads[ gtid ]; |
| kmp_depnode_t *node = task->td_depnode; |
| |
| if ( task->td_dephash ) { |
| KA_TRACE(40, ("__kmp_realease_deps: T#%d freeing dependencies hash of task %p.\n", gtid, task ) ); |
| __kmp_dephash_free(thread,task->td_dephash); |
| } |
| |
| if ( !node ) return; |
| |
| KA_TRACE(20, ("__kmp_realease_deps: T#%d notifying succesors of task %p.\n", gtid, task ) ); |
| |
| KMP_ACQUIRE_DEPNODE(gtid,node); |
| node->dn.task = NULL; // mark this task as finished, so no new dependencies are generated |
| KMP_RELEASE_DEPNODE(gtid,node); |
| |
| kmp_depnode_list_t *next; |
| for ( kmp_depnode_list_t *p = node->dn.successors; p; p = next ) { |
| kmp_depnode_t *successor = p->node; |
| kmp_int32 npredecessors = KMP_TEST_THEN_DEC32(&successor->dn.npredecessors) - 1; |
| |
| // successor task can be NULL for wait_depends or because deps are still being processed |
| if ( npredecessors == 0 ) { |
| KMP_MB(); |
| if ( successor->dn.task ) { |
| KA_TRACE(20, ("__kmp_realease_deps: T#%d successor %p of %p scheduled for execution.\n", gtid, successor->dn.task, task ) ); |
| __kmp_omp_task(gtid,successor->dn.task,false); |
| } |
| } |
| |
| next = p->next; |
| __kmp_node_deref(thread,p->node); |
| #if USE_FAST_MEMORY |
| __kmp_fast_free(thread,p); |
| #else |
| __kmp_thread_free(thread,p); |
| #endif |
| } |
| |
| __kmp_node_deref(thread,node); |
| |
| KA_TRACE(20, ("__kmp_realease_deps: T#%d all successors of %p notified of completation\n", gtid, task ) ); |
| } |
| |
| /*! |
| @ingroup TASKING |
| @param loc_ref location of the original task directive |
| @param gtid Global Thread ID of encountering thread |
| @param new_task task thunk allocated by __kmp_omp_task_alloc() for the ''new task'' |
| @param ndeps Number of depend items with possible aliasing |
| @param dep_list List of depend items with possible aliasing |
| @param ndeps_noalias Number of depend items with no aliasing |
| @param noalias_dep_list List of depend items with no aliasing |
| |
| @return Returns either TASK_CURRENT_NOT_QUEUED if the current task was not suspendend and queued, or TASK_CURRENT_QUEUED if it was suspended and queued |
| |
| Schedule a non-thread-switchable task with dependences for execution |
| */ |
| kmp_int32 |
| __kmpc_omp_task_with_deps( ident_t *loc_ref, kmp_int32 gtid, kmp_task_t * new_task, |
| kmp_int32 ndeps, kmp_depend_info_t *dep_list, |
| kmp_int32 ndeps_noalias, kmp_depend_info_t *noalias_dep_list ) |
| { |
| |
| kmp_taskdata_t * new_taskdata = KMP_TASK_TO_TASKDATA(new_task); |
| KA_TRACE(10, ("__kmpc_omp_task_with_deps(enter): T#%d loc=%p task=%p\n", |
| gtid, loc_ref, new_taskdata ) ); |
| |
| kmp_info_t *thread = __kmp_threads[ gtid ]; |
| kmp_taskdata_t * current_task = thread->th.th_current_task; |
| |
| bool serial = current_task->td_flags.team_serial || current_task->td_flags.tasking_ser || current_task->td_flags.final; |
| |
| if ( !serial && ( ndeps > 0 || ndeps_noalias > 0 )) { |
| /* if no dependencies have been tracked yet, create the dependence hash */ |
| if ( current_task->td_dephash == NULL ) |
| current_task->td_dephash = __kmp_dephash_create(thread); |
| |
| #if USE_FAST_MEMORY |
| kmp_depnode_t *node = (kmp_depnode_t *) __kmp_fast_allocate(thread,sizeof(kmp_depnode_t)); |
| #else |
| kmp_depnode_t *node = (kmp_depnode_t *) __kmp_thread_malloc(thread,sizeof(kmp_depnode_t)); |
| #endif |
| |
| __kmp_init_node(node); |
| new_taskdata->td_depnode = node; |
| |
| if ( __kmp_check_deps( gtid, node, new_task, current_task->td_dephash, NO_DEP_BARRIER, |
| ndeps, dep_list, ndeps_noalias,noalias_dep_list ) ) { |
| KA_TRACE(10, ("__kmpc_omp_task_with_deps(exit): T#%d task had blocking dependencies: " |
| "loc=%p task=%p, return: TASK_CURRENT_NOT_QUEUED\n", gtid, loc_ref, |
| new_taskdata ) ); |
| return TASK_CURRENT_NOT_QUEUED; |
| } |
| } |
| |
| KA_TRACE(10, ("__kmpc_omp_task_with_deps(exit): T#%d task had no blocking dependencies : " |
| "loc=%p task=%p, transferring to __kmpc_omp_task\n", gtid, loc_ref, |
| new_taskdata ) ); |
| |
| return __kmpc_omp_task(loc_ref,gtid,new_task); |
| } |
| |
| /*! |
| @ingroup TASKING |
| @param loc_ref location of the original task directive |
| @param gtid Global Thread ID of encountering thread |
| @param ndeps Number of depend items with possible aliasing |
| @param dep_list List of depend items with possible aliasing |
| @param ndeps_noalias Number of depend items with no aliasing |
| @param noalias_dep_list List of depend items with no aliasing |
| |
| Blocks the current task until all specifies dependencies have been fulfilled. |
| */ |
| void |
| __kmpc_omp_wait_deps ( ident_t *loc_ref, kmp_int32 gtid, kmp_int32 ndeps, kmp_depend_info_t *dep_list, |
| kmp_int32 ndeps_noalias, kmp_depend_info_t *noalias_dep_list ) |
| { |
| KA_TRACE(10, ("__kmpc_omp_wait_deps(enter): T#%d loc=%p\n", gtid, loc_ref) ); |
| |
| if ( ndeps == 0 && ndeps_noalias == 0 ) { |
| KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d has no dependencies to wait upon : loc=%p\n", gtid, loc_ref) ); |
| return; |
| } |
| |
| kmp_info_t *thread = __kmp_threads[ gtid ]; |
| kmp_taskdata_t * current_task = thread->th.th_current_task; |
| |
| // We can return immediately as: |
| // - dependences are not computed in serial teams |
| // - if the dephash is not yet created it means we have nothing to wait for |
| if ( current_task->td_flags.team_serial || current_task->td_flags.tasking_ser || current_task->td_flags.final || current_task->td_dephash == NULL ) { |
| KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d has no blocking dependencies : loc=%p\n", gtid, loc_ref) ); |
| return; |
| } |
| |
| kmp_depnode_t node; |
| __kmp_init_node(&node); |
| |
| if (!__kmp_check_deps( gtid, &node, NULL, current_task->td_dephash, DEP_BARRIER, |
| ndeps, dep_list, ndeps_noalias, noalias_dep_list )) { |
| KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d has no blocking dependencies : loc=%p\n", gtid, loc_ref) ); |
| return; |
| } |
| |
| int thread_finished = FALSE; |
| kmp_flag_32 flag((volatile kmp_uint32 *)&(node.dn.npredecessors), 0U); |
| while ( node.dn.npredecessors > 0 ) { |
| flag.execute_tasks(thread, gtid, FALSE, &thread_finished, |
| #if USE_ITT_BUILD |
| NULL, |
| #endif |
| __kmp_task_stealing_constraint ); |
| } |
| |
| KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d finished waiting : loc=%p\n", gtid, loc_ref) ); |
| } |
| |
| #endif /* OMP_40_ENABLED */ |
| |