1 /* 2 * kmp_taskdeps.cpp 3 */ 4 5 6 //===----------------------------------------------------------------------===// 7 // 8 // The LLVM Compiler Infrastructure 9 // 10 // This file is dual licensed under the MIT and the University of Illinois Open 11 // Source Licenses. See LICENSE.txt for details. 12 // 13 //===----------------------------------------------------------------------===// 14 15 16 //#define KMP_SUPPORT_GRAPH_OUTPUT 1 17 18 #include "kmp.h" 19 #include "kmp_io.h" 20 #include "kmp_wait_release.h" 21 22 #if OMP_40_ENABLED 23 24 //TODO: Improve memory allocation? keep a list of pre-allocated structures? allocate in blocks? re-use list finished list entries? 25 //TODO: don't use atomic ref counters for stack-allocated nodes. 26 //TODO: find an alternate to atomic refs for heap-allocated nodes? 27 //TODO: Finish graph output support 28 //TODO: kmp_lock_t seems a tad to big (and heavy weight) for this. Check other runtime locks 29 //TODO: Any ITT support needed? 30 31 #ifdef KMP_SUPPORT_GRAPH_OUTPUT 32 static kmp_int32 kmp_node_id_seed = 0; 33 #endif 34 35 static void 36 __kmp_init_node ( kmp_depnode_t *node ) 37 { 38 node->dn.task = NULL; // set to null initially, it will point to the right task once dependences have been processed 39 node->dn.successors = NULL; 40 __kmp_init_lock(&node->dn.lock); 41 node->dn.nrefs = 1; // init creates the first reference to the node 42 #ifdef KMP_SUPPORT_GRAPH_OUTPUT 43 node->dn.id = KMP_TEST_THEN_INC32(&kmp_node_id_seed); 44 #endif 45 } 46 47 static inline kmp_depnode_t * 48 __kmp_node_ref ( kmp_depnode_t *node ) 49 { 50 KMP_TEST_THEN_INC32(&node->dn.nrefs); 51 return node; 52 } 53 54 static inline void 55 __kmp_node_deref ( kmp_info_t *thread, kmp_depnode_t *node ) 56 { 57 if (!node) return; 58 59 kmp_int32 n = KMP_TEST_THEN_DEC32(&node->dn.nrefs) - 1; 60 if ( n == 0 ) { 61 KMP_ASSERT(node->dn.nrefs == 0); 62 #if USE_FAST_MEMORY 63 __kmp_fast_free(thread,node); 64 #else 65 __kmp_thread_free(thread,node); 66 #endif 67 } 68 } 69 70 #define KMP_ACQUIRE_DEPNODE(gtid,n) __kmp_acquire_lock(&(n)->dn.lock,(gtid)) 71 #define KMP_RELEASE_DEPNODE(gtid,n) __kmp_release_lock(&(n)->dn.lock,(gtid)) 72 73 static void 74 __kmp_depnode_list_free ( kmp_info_t *thread, kmp_depnode_list *list ); 75 76 enum { 77 KMP_DEPHASH_OTHER_SIZE = 97, 78 KMP_DEPHASH_MASTER_SIZE = 997 79 }; 80 81 static inline kmp_int32 82 __kmp_dephash_hash ( kmp_intptr_t addr, size_t hsize ) 83 { 84 //TODO alternate to try: set = (((Addr64)(addrUsefulBits * 9.618)) % m_num_sets ); 85 return ((addr >> 6) ^ (addr >> 2)) % hsize; 86 } 87 88 static kmp_dephash_t * 89 __kmp_dephash_create ( kmp_info_t *thread, kmp_taskdata_t *current_task ) 90 { 91 kmp_dephash_t *h; 92 93 size_t h_size; 94 95 if ( current_task->td_flags.tasktype == TASK_IMPLICIT ) 96 h_size = KMP_DEPHASH_MASTER_SIZE; 97 else 98 h_size = KMP_DEPHASH_OTHER_SIZE; 99 100 kmp_int32 size = h_size * sizeof(kmp_dephash_entry_t) + sizeof(kmp_dephash_t); 101 102 #if USE_FAST_MEMORY 103 h = (kmp_dephash_t *) __kmp_fast_allocate( thread, size ); 104 #else 105 h = (kmp_dephash_t *) __kmp_thread_malloc( thread, size ); 106 #endif 107 h->size = h_size; 108 109 #ifdef KMP_DEBUG 110 h->nelements = 0; 111 h->nconflicts = 0; 112 #endif 113 h->buckets = (kmp_dephash_entry **)(h+1); 114 115 for ( size_t i = 0; i < h_size; i++ ) 116 h->buckets[i] = 0; 117 118 return h; 119 } 120 121 static void 122 __kmp_dephash_free ( kmp_info_t *thread, kmp_dephash_t *h ) 123 { 124 for ( size_t i=0; i < h->size; i++ ) { 125 if ( h->buckets[i] ) { 126 kmp_dephash_entry_t *next; 127 for ( kmp_dephash_entry_t *entry = h->buckets[i]; entry; entry = next ) { 128 next = entry->next_in_bucket; 129 __kmp_depnode_list_free(thread,entry->last_ins); 130 __kmp_node_deref(thread,entry->last_out); 131 #if USE_FAST_MEMORY 132 __kmp_fast_free(thread,entry); 133 #else 134 __kmp_thread_free(thread,entry); 135 #endif 136 } 137 } 138 } 139 #if USE_FAST_MEMORY 140 __kmp_fast_free(thread,h); 141 #else 142 __kmp_thread_free(thread,h); 143 #endif 144 } 145 146 static kmp_dephash_entry * 147 __kmp_dephash_find ( kmp_info_t *thread, kmp_dephash_t *h, kmp_intptr_t addr ) 148 { 149 kmp_int32 bucket = __kmp_dephash_hash(addr,h->size); 150 151 kmp_dephash_entry_t *entry; 152 for ( entry = h->buckets[bucket]; entry; entry = entry->next_in_bucket ) 153 if ( entry->addr == addr ) break; 154 155 if ( entry == NULL ) { 156 // create entry. This is only done by one thread so no locking required 157 #if USE_FAST_MEMORY 158 entry = (kmp_dephash_entry_t *) __kmp_fast_allocate( thread, sizeof(kmp_dephash_entry_t) ); 159 #else 160 entry = (kmp_dephash_entry_t *) __kmp_thread_malloc( thread, sizeof(kmp_dephash_entry_t) ); 161 #endif 162 entry->addr = addr; 163 entry->last_out = NULL; 164 entry->last_ins = NULL; 165 entry->next_in_bucket = h->buckets[bucket]; 166 h->buckets[bucket] = entry; 167 #ifdef KMP_DEBUG 168 h->nelements++; 169 if ( entry->next_in_bucket ) h->nconflicts++; 170 #endif 171 } 172 return entry; 173 } 174 175 static kmp_depnode_list_t * 176 __kmp_add_node ( kmp_info_t *thread, kmp_depnode_list_t *list, kmp_depnode_t *node ) 177 { 178 kmp_depnode_list_t *new_head; 179 180 #if USE_FAST_MEMORY 181 new_head = (kmp_depnode_list_t *) __kmp_fast_allocate(thread,sizeof(kmp_depnode_list_t)); 182 #else 183 new_head = (kmp_depnode_list_t *) __kmp_thread_malloc(thread,sizeof(kmp_depnode_list_t)); 184 #endif 185 186 new_head->node = __kmp_node_ref(node); 187 new_head->next = list; 188 189 return new_head; 190 } 191 192 static void 193 __kmp_depnode_list_free ( kmp_info_t *thread, kmp_depnode_list *list ) 194 { 195 kmp_depnode_list *next; 196 197 for ( ; list ; list = next ) { 198 next = list->next; 199 200 __kmp_node_deref(thread,list->node); 201 #if USE_FAST_MEMORY 202 __kmp_fast_free(thread,list); 203 #else 204 __kmp_thread_free(thread,list); 205 #endif 206 } 207 } 208 209 static inline void 210 __kmp_track_dependence ( kmp_depnode_t *source, kmp_depnode_t *sink, 211 kmp_task_t *sink_task ) 212 { 213 #ifdef KMP_SUPPORT_GRAPH_OUTPUT 214 kmp_taskdata_t * task_source = KMP_TASK_TO_TASKDATA(source->dn.task); 215 kmp_taskdata_t * task_sink = KMP_TASK_TO_TASKDATA(sink->dn.task); // this can be NULL when if(0) ... 216 217 __kmp_printf("%d(%s) -> %d(%s)\n", source->dn.id, task_source->td_ident->psource, sink->dn.id, task_sink->td_ident->psource); 218 #endif 219 #if OMPT_SUPPORT && OMPT_TRACE 220 /* OMPT tracks dependences between task (a=source, b=sink) in which 221 task a blocks the execution of b through the ompt_new_dependence_callback */ 222 if (ompt_enabled && 223 ompt_callbacks.ompt_callback(ompt_event_task_dependence_pair)) 224 { 225 kmp_taskdata_t * task_source = KMP_TASK_TO_TASKDATA(source->dn.task); 226 kmp_taskdata_t * task_sink = KMP_TASK_TO_TASKDATA(sink_task); 227 228 ompt_callbacks.ompt_callback(ompt_event_task_dependence_pair)( 229 task_source->ompt_task_info.task_id, 230 task_sink->ompt_task_info.task_id); 231 } 232 #endif /* OMPT_SUPPORT && OMPT_TRACE */ 233 } 234 235 template< bool filter > 236 static inline kmp_int32 237 __kmp_process_deps ( kmp_int32 gtid, kmp_depnode_t *node, kmp_dephash_t *hash, 238 bool dep_barrier,kmp_int32 ndeps, kmp_depend_info_t *dep_list, 239 kmp_task_t *task ) 240 { 241 KA_TRACE(30, ("__kmp_process_deps<%d>: T#%d processing %d depencies : dep_barrier = %d\n", filter, gtid, ndeps, dep_barrier ) ); 242 243 kmp_info_t *thread = __kmp_threads[ gtid ]; 244 kmp_int32 npredecessors=0; 245 for ( kmp_int32 i = 0; i < ndeps ; i++ ) { 246 const kmp_depend_info_t * dep = &dep_list[i]; 247 248 KMP_DEBUG_ASSERT(dep->flags.in); 249 250 if ( filter && dep->base_addr == 0 ) continue; // skip filtered entries 251 252 kmp_dephash_entry_t *info = __kmp_dephash_find(thread,hash,dep->base_addr); 253 kmp_depnode_t *last_out = info->last_out; 254 255 if ( dep->flags.out && info->last_ins ) { 256 for ( kmp_depnode_list_t * p = info->last_ins; p; p = p->next ) { 257 kmp_depnode_t * indep = p->node; 258 if ( indep->dn.task ) { 259 KMP_ACQUIRE_DEPNODE(gtid,indep); 260 if ( indep->dn.task ) { 261 __kmp_track_dependence(indep,node,task); 262 indep->dn.successors = __kmp_add_node(thread, indep->dn.successors, node); 263 KA_TRACE(40,("__kmp_process_deps<%d>: T#%d adding dependence from %p to %p\n", 264 filter,gtid, KMP_TASK_TO_TASKDATA(indep->dn.task), KMP_TASK_TO_TASKDATA(node->dn.task))); 265 npredecessors++; 266 } 267 KMP_RELEASE_DEPNODE(gtid,indep); 268 } 269 } 270 271 __kmp_depnode_list_free(thread,info->last_ins); 272 info->last_ins = NULL; 273 274 } else if ( last_out && last_out->dn.task ) { 275 KMP_ACQUIRE_DEPNODE(gtid,last_out); 276 if ( last_out->dn.task ) { 277 __kmp_track_dependence(last_out,node,task); 278 last_out->dn.successors = __kmp_add_node(thread, last_out->dn.successors, node); 279 KA_TRACE(40,("__kmp_process_deps<%d>: T#%d adding dependence from %p to %p\n", 280 filter,gtid, KMP_TASK_TO_TASKDATA(last_out->dn.task), KMP_TASK_TO_TASKDATA(node->dn.task))); 281 282 npredecessors++; 283 } 284 KMP_RELEASE_DEPNODE(gtid,last_out); 285 } 286 287 if ( dep_barrier ) { 288 // if this is a sync point in the serial sequence, then the previous outputs are guaranteed to be completed after 289 // the execution of this task so the previous output nodes can be cleared. 290 __kmp_node_deref(thread,last_out); 291 info->last_out = NULL; 292 } else { 293 if ( dep->flags.out ) { 294 __kmp_node_deref(thread,last_out); 295 info->last_out = __kmp_node_ref(node); 296 } else 297 info->last_ins = __kmp_add_node(thread, info->last_ins, node); 298 } 299 300 } 301 302 KA_TRACE(30, ("__kmp_process_deps<%d>: T#%d found %d predecessors\n", filter, gtid, npredecessors ) ); 303 304 return npredecessors; 305 } 306 307 #define NO_DEP_BARRIER (false) 308 #define DEP_BARRIER (true) 309 310 // returns true if the task has any outstanding dependence 311 static bool 312 __kmp_check_deps ( kmp_int32 gtid, kmp_depnode_t *node, kmp_task_t *task, kmp_dephash_t *hash, bool dep_barrier, 313 kmp_int32 ndeps, kmp_depend_info_t *dep_list, 314 kmp_int32 ndeps_noalias, kmp_depend_info_t *noalias_dep_list ) 315 { 316 int i; 317 318 #if KMP_DEBUG 319 kmp_taskdata_t * taskdata = KMP_TASK_TO_TASKDATA(task); 320 #endif 321 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 ) ); 322 323 // Filter deps in dep_list 324 // TODO: Different algorithm for large dep_list ( > 10 ? ) 325 for ( i = 0; i < ndeps; i ++ ) { 326 if ( dep_list[i].base_addr != 0 ) 327 for ( int j = i+1; j < ndeps; j++ ) 328 if ( dep_list[i].base_addr == dep_list[j].base_addr ) { 329 dep_list[i].flags.in |= dep_list[j].flags.in; 330 dep_list[i].flags.out |= dep_list[j].flags.out; 331 dep_list[j].base_addr = 0; // Mark j element as void 332 } 333 } 334 335 // doesn't need to be atomic as no other thread is going to be accessing this node just yet 336 // npredecessors is set -1 to ensure that none of the releasing tasks queues this task before we have finished processing all the dependencies 337 node->dn.npredecessors = -1; 338 339 // used to pack all npredecessors additions into a single atomic operation at the end 340 int npredecessors; 341 342 npredecessors = __kmp_process_deps<true>(gtid, node, hash, dep_barrier, 343 ndeps, dep_list, task); 344 npredecessors += __kmp_process_deps<false>(gtid, node, hash, dep_barrier, 345 ndeps_noalias, noalias_dep_list, task); 346 347 node->dn.task = task; 348 KMP_MB(); 349 350 // Account for our initial fake value 351 npredecessors++; 352 353 // 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) 354 npredecessors = KMP_TEST_THEN_ADD32(&node->dn.npredecessors, npredecessors) + npredecessors; 355 356 KA_TRACE(20, ("__kmp_check_deps: T#%d found %d predecessors for task %p \n", gtid, npredecessors, taskdata ) ); 357 358 // beyond this point the task could be queued (and executed) by a releasing task... 359 return npredecessors > 0 ? true : false; 360 } 361 362 void 363 __kmp_release_deps ( kmp_int32 gtid, kmp_taskdata_t *task ) 364 { 365 kmp_info_t *thread = __kmp_threads[ gtid ]; 366 kmp_depnode_t *node = task->td_depnode; 367 368 if ( task->td_dephash ) { 369 KA_TRACE(40, ("__kmp_realease_deps: T#%d freeing dependencies hash of task %p.\n", gtid, task ) ); 370 __kmp_dephash_free(thread,task->td_dephash); 371 } 372 373 if ( !node ) return; 374 375 KA_TRACE(20, ("__kmp_realease_deps: T#%d notifying succesors of task %p.\n", gtid, task ) ); 376 377 KMP_ACQUIRE_DEPNODE(gtid,node); 378 node->dn.task = NULL; // mark this task as finished, so no new dependencies are generated 379 KMP_RELEASE_DEPNODE(gtid,node); 380 381 kmp_depnode_list_t *next; 382 for ( kmp_depnode_list_t *p = node->dn.successors; p; p = next ) { 383 kmp_depnode_t *successor = p->node; 384 kmp_int32 npredecessors = KMP_TEST_THEN_DEC32(&successor->dn.npredecessors) - 1; 385 386 // successor task can be NULL for wait_depends or because deps are still being processed 387 if ( npredecessors == 0 ) { 388 KMP_MB(); 389 if ( successor->dn.task ) { 390 KA_TRACE(20, ("__kmp_realease_deps: T#%d successor %p of %p scheduled for execution.\n", gtid, successor->dn.task, task ) ); 391 __kmp_omp_task(gtid,successor->dn.task,false); 392 } 393 } 394 395 next = p->next; 396 __kmp_node_deref(thread,p->node); 397 #if USE_FAST_MEMORY 398 __kmp_fast_free(thread,p); 399 #else 400 __kmp_thread_free(thread,p); 401 #endif 402 } 403 404 __kmp_node_deref(thread,node); 405 406 KA_TRACE(20, ("__kmp_realease_deps: T#%d all successors of %p notified of completation\n", gtid, task ) ); 407 } 408 409 /*! 410 @ingroup TASKING 411 @param loc_ref location of the original task directive 412 @param gtid Global Thread ID of encountering thread 413 @param new_task task thunk allocated by __kmp_omp_task_alloc() for the ''new task'' 414 @param ndeps Number of depend items with possible aliasing 415 @param dep_list List of depend items with possible aliasing 416 @param ndeps_noalias Number of depend items with no aliasing 417 @param noalias_dep_list List of depend items with no aliasing 418 419 @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 420 421 Schedule a non-thread-switchable task with dependences for execution 422 */ 423 kmp_int32 424 __kmpc_omp_task_with_deps( ident_t *loc_ref, kmp_int32 gtid, kmp_task_t * new_task, 425 kmp_int32 ndeps, kmp_depend_info_t *dep_list, 426 kmp_int32 ndeps_noalias, kmp_depend_info_t *noalias_dep_list ) 427 { 428 429 kmp_taskdata_t * new_taskdata = KMP_TASK_TO_TASKDATA(new_task); 430 KA_TRACE(10, ("__kmpc_omp_task_with_deps(enter): T#%d loc=%p task=%p\n", 431 gtid, loc_ref, new_taskdata ) ); 432 433 kmp_info_t *thread = __kmp_threads[ gtid ]; 434 kmp_taskdata_t * current_task = thread->th.th_current_task; 435 436 #if OMPT_SUPPORT && OMPT_TRACE 437 /* OMPT grab all dependences if requested by the tool */ 438 if (ompt_enabled && ndeps+ndeps_noalias > 0 && 439 ompt_callbacks.ompt_callback(ompt_event_task_dependences)) 440 { 441 kmp_int32 i; 442 443 new_taskdata->ompt_task_info.ndeps = ndeps+ndeps_noalias; 444 new_taskdata->ompt_task_info.deps = (ompt_task_dependence_t *) 445 KMP_OMPT_DEPS_ALLOC(thread, 446 (ndeps+ndeps_noalias)*sizeof(ompt_task_dependence_t)); 447 448 KMP_ASSERT(new_taskdata->ompt_task_info.deps != NULL); 449 450 for (i = 0; i < ndeps; i++) 451 { 452 new_taskdata->ompt_task_info.deps[i].variable_addr = 453 (void*) dep_list[i].base_addr; 454 if (dep_list[i].flags.in && dep_list[i].flags.out) 455 new_taskdata->ompt_task_info.deps[i].dependence_flags = 456 ompt_task_dependence_type_inout; 457 else if (dep_list[i].flags.out) 458 new_taskdata->ompt_task_info.deps[i].dependence_flags = 459 ompt_task_dependence_type_out; 460 else if (dep_list[i].flags.in) 461 new_taskdata->ompt_task_info.deps[i].dependence_flags = 462 ompt_task_dependence_type_in; 463 } 464 for (i = 0; i < ndeps_noalias; i++) 465 { 466 new_taskdata->ompt_task_info.deps[ndeps+i].variable_addr = 467 (void*) noalias_dep_list[i].base_addr; 468 if (noalias_dep_list[i].flags.in && noalias_dep_list[i].flags.out) 469 new_taskdata->ompt_task_info.deps[ndeps+i].dependence_flags = 470 ompt_task_dependence_type_inout; 471 else if (noalias_dep_list[i].flags.out) 472 new_taskdata->ompt_task_info.deps[ndeps+i].dependence_flags = 473 ompt_task_dependence_type_out; 474 else if (noalias_dep_list[i].flags.in) 475 new_taskdata->ompt_task_info.deps[ndeps+i].dependence_flags = 476 ompt_task_dependence_type_in; 477 } 478 } 479 #endif /* OMPT_SUPPORT && OMPT_TRACE */ 480 481 bool serial = current_task->td_flags.team_serial || current_task->td_flags.tasking_ser || current_task->td_flags.final; 482 #if OMP_45_ENABLED 483 serial = serial && !(new_taskdata->td_flags.proxy == TASK_PROXY); 484 #endif 485 486 if ( !serial && ( ndeps > 0 || ndeps_noalias > 0 )) { 487 /* if no dependencies have been tracked yet, create the dependence hash */ 488 if ( current_task->td_dephash == NULL ) 489 current_task->td_dephash = __kmp_dephash_create(thread, current_task); 490 491 #if USE_FAST_MEMORY 492 kmp_depnode_t *node = (kmp_depnode_t *) __kmp_fast_allocate(thread,sizeof(kmp_depnode_t)); 493 #else 494 kmp_depnode_t *node = (kmp_depnode_t *) __kmp_thread_malloc(thread,sizeof(kmp_depnode_t)); 495 #endif 496 497 __kmp_init_node(node); 498 new_taskdata->td_depnode = node; 499 500 if ( __kmp_check_deps( gtid, node, new_task, current_task->td_dephash, NO_DEP_BARRIER, 501 ndeps, dep_list, ndeps_noalias,noalias_dep_list ) ) { 502 KA_TRACE(10, ("__kmpc_omp_task_with_deps(exit): T#%d task had blocking dependencies: " 503 "loc=%p task=%p, return: TASK_CURRENT_NOT_QUEUED\n", gtid, loc_ref, 504 new_taskdata ) ); 505 return TASK_CURRENT_NOT_QUEUED; 506 } 507 } else { 508 #if OMP_45_ENABLED 509 kmp_task_team_t * task_team = thread->th.th_task_team; 510 if ( task_team && task_team->tt.tt_found_proxy_tasks ) 511 __kmpc_omp_wait_deps ( loc_ref, gtid, ndeps, dep_list, ndeps_noalias, noalias_dep_list ); 512 else 513 #endif 514 KA_TRACE(10, ("__kmpc_omp_task_with_deps(exit): T#%d ignored dependencies for task (serialized)" 515 "loc=%p task=%p\n", gtid, loc_ref, new_taskdata ) ); 516 } 517 518 KA_TRACE(10, ("__kmpc_omp_task_with_deps(exit): T#%d task had no blocking dependencies : " 519 "loc=%p task=%p, transferring to __kmpc_omp_task\n", gtid, loc_ref, 520 new_taskdata ) ); 521 522 return __kmpc_omp_task(loc_ref,gtid,new_task); 523 } 524 525 /*! 526 @ingroup TASKING 527 @param loc_ref location of the original task directive 528 @param gtid Global Thread ID of encountering thread 529 @param ndeps Number of depend items with possible aliasing 530 @param dep_list List of depend items with possible aliasing 531 @param ndeps_noalias Number of depend items with no aliasing 532 @param noalias_dep_list List of depend items with no aliasing 533 534 Blocks the current task until all specifies dependencies have been fulfilled. 535 */ 536 void 537 __kmpc_omp_wait_deps ( ident_t *loc_ref, kmp_int32 gtid, kmp_int32 ndeps, kmp_depend_info_t *dep_list, 538 kmp_int32 ndeps_noalias, kmp_depend_info_t *noalias_dep_list ) 539 { 540 KA_TRACE(10, ("__kmpc_omp_wait_deps(enter): T#%d loc=%p\n", gtid, loc_ref) ); 541 542 if ( ndeps == 0 && ndeps_noalias == 0 ) { 543 KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d has no dependencies to wait upon : loc=%p\n", gtid, loc_ref) ); 544 return; 545 } 546 547 kmp_info_t *thread = __kmp_threads[ gtid ]; 548 kmp_taskdata_t * current_task = thread->th.th_current_task; 549 550 // We can return immediately as: 551 // - dependences are not computed in serial teams (except if we have proxy tasks) 552 // - if the dephash is not yet created it means we have nothing to wait for 553 bool ignore = current_task->td_flags.team_serial || current_task->td_flags.tasking_ser || current_task->td_flags.final; 554 #if OMP_45_ENABLED 555 ignore = ignore && thread->th.th_task_team != NULL && thread->th.th_task_team->tt.tt_found_proxy_tasks == FALSE; 556 #endif 557 ignore = ignore || current_task->td_dephash == NULL; 558 559 if ( ignore ) { 560 KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d has no blocking dependencies : loc=%p\n", gtid, loc_ref) ); 561 return; 562 } 563 564 kmp_depnode_t node; 565 __kmp_init_node(&node); 566 567 if (!__kmp_check_deps( gtid, &node, NULL, current_task->td_dephash, DEP_BARRIER, 568 ndeps, dep_list, ndeps_noalias, noalias_dep_list )) { 569 KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d has no blocking dependencies : loc=%p\n", gtid, loc_ref) ); 570 return; 571 } 572 573 int thread_finished = FALSE; 574 kmp_flag_32 flag((volatile kmp_uint32 *)&(node.dn.npredecessors), 0U); 575 while ( node.dn.npredecessors > 0 ) { 576 flag.execute_tasks(thread, gtid, FALSE, &thread_finished, 577 #if USE_ITT_BUILD 578 NULL, 579 #endif 580 __kmp_task_stealing_constraint ); 581 } 582 583 KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d finished waiting : loc=%p\n", gtid, loc_ref) ); 584 } 585 586 #endif /* OMP_40_ENABLED */ 587 588