LLVM OpenMP* Runtime Library
kmp_taskdeps.cpp
1 /*
2  * kmp_taskdeps.cpp
3  */
4 
5 //===----------------------------------------------------------------------===//
6 //
7 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
8 // See https://llvm.org/LICENSE.txt for license information.
9 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
10 //
11 //===----------------------------------------------------------------------===//
12 
13 //#define KMP_SUPPORT_GRAPH_OUTPUT 1
14 
15 #include "kmp.h"
16 #include "kmp_io.h"
17 #include "kmp_wait_release.h"
18 #include "kmp_taskdeps.h"
19 #if OMPT_SUPPORT
20 #include "ompt-specific.h"
21 #endif
22 
23 #if OMP_40_ENABLED
24 
25 // TODO: Improve memory allocation? keep a list of pre-allocated structures?
26 // allocate in blocks? re-use list finished list entries?
27 // TODO: don't use atomic ref counters for stack-allocated nodes.
28 // TODO: find an alternate to atomic refs for heap-allocated nodes?
29 // TODO: Finish graph output support
30 // TODO: kmp_lock_t seems a tad to big (and heavy weight) for this. Check other
31 // runtime locks
32 // TODO: Any ITT support needed?
33 
34 #ifdef KMP_SUPPORT_GRAPH_OUTPUT
35 static std::atomic<kmp_int32> kmp_node_id_seed = ATOMIC_VAR_INIT(0);
36 #endif
37 
38 static void __kmp_init_node(kmp_depnode_t *node) {
39  node->dn.successors = NULL;
40  node->dn.task = NULL; // will point to the rigth task
41  // once dependences have been processed
42  for (int i = 0; i < MAX_MTX_DEPS; ++i)
43  node->dn.mtx_locks[i] = NULL;
44  node->dn.mtx_num_locks = 0;
45  __kmp_init_lock(&node->dn.lock);
46  KMP_ATOMIC_ST_RLX(&node->dn.nrefs, 1); // init creates the first reference
47 #ifdef KMP_SUPPORT_GRAPH_OUTPUT
48  node->dn.id = KMP_ATOMIC_INC(&kmp_node_id_seed);
49 #endif
50 }
51 
52 static inline kmp_depnode_t *__kmp_node_ref(kmp_depnode_t *node) {
53  KMP_ATOMIC_INC(&node->dn.nrefs);
54  return node;
55 }
56 
57 enum { KMP_DEPHASH_OTHER_SIZE = 97, KMP_DEPHASH_MASTER_SIZE = 997 };
58 
59 static inline kmp_int32 __kmp_dephash_hash(kmp_intptr_t addr, size_t hsize) {
60  // TODO alternate to try: set = (((Addr64)(addrUsefulBits * 9.618)) %
61  // m_num_sets );
62  return ((addr >> 6) ^ (addr >> 2)) % hsize;
63 }
64 
65 static kmp_dephash_t *__kmp_dephash_create(kmp_info_t *thread,
66  kmp_taskdata_t *current_task) {
67  kmp_dephash_t *h;
68 
69  size_t h_size;
70 
71  if (current_task->td_flags.tasktype == TASK_IMPLICIT)
72  h_size = KMP_DEPHASH_MASTER_SIZE;
73  else
74  h_size = KMP_DEPHASH_OTHER_SIZE;
75 
76  kmp_int32 size =
77  h_size * sizeof(kmp_dephash_entry_t *) + sizeof(kmp_dephash_t);
78 
79 #if USE_FAST_MEMORY
80  h = (kmp_dephash_t *)__kmp_fast_allocate(thread, size);
81 #else
82  h = (kmp_dephash_t *)__kmp_thread_malloc(thread, size);
83 #endif
84  h->size = h_size;
85 
86 #ifdef KMP_DEBUG
87  h->nelements = 0;
88  h->nconflicts = 0;
89 #endif
90  h->buckets = (kmp_dephash_entry **)(h + 1);
91 
92  for (size_t i = 0; i < h_size; i++)
93  h->buckets[i] = 0;
94 
95  return h;
96 }
97 
98 #define ENTRY_LAST_INS 0
99 #define ENTRY_LAST_MTXS 1
100 
101 static kmp_dephash_entry *
102 __kmp_dephash_find(kmp_info_t *thread, kmp_dephash_t *h, kmp_intptr_t addr) {
103  kmp_int32 bucket = __kmp_dephash_hash(addr, h->size);
104 
105  kmp_dephash_entry_t *entry;
106  for (entry = h->buckets[bucket]; entry; entry = entry->next_in_bucket)
107  if (entry->addr == addr)
108  break;
109 
110  if (entry == NULL) {
111 // create entry. This is only done by one thread so no locking required
112 #if USE_FAST_MEMORY
113  entry = (kmp_dephash_entry_t *)__kmp_fast_allocate(
114  thread, sizeof(kmp_dephash_entry_t));
115 #else
116  entry = (kmp_dephash_entry_t *)__kmp_thread_malloc(
117  thread, sizeof(kmp_dephash_entry_t));
118 #endif
119  entry->addr = addr;
120  entry->last_out = NULL;
121  entry->last_ins = NULL;
122  entry->last_mtxs = NULL;
123  entry->last_flag = ENTRY_LAST_INS;
124  entry->mtx_lock = NULL;
125  entry->next_in_bucket = h->buckets[bucket];
126  h->buckets[bucket] = entry;
127 #ifdef KMP_DEBUG
128  h->nelements++;
129  if (entry->next_in_bucket)
130  h->nconflicts++;
131 #endif
132  }
133  return entry;
134 }
135 
136 static kmp_depnode_list_t *__kmp_add_node(kmp_info_t *thread,
137  kmp_depnode_list_t *list,
138  kmp_depnode_t *node) {
139  kmp_depnode_list_t *new_head;
140 
141 #if USE_FAST_MEMORY
142  new_head = (kmp_depnode_list_t *)__kmp_fast_allocate(
143  thread, sizeof(kmp_depnode_list_t));
144 #else
145  new_head = (kmp_depnode_list_t *)__kmp_thread_malloc(
146  thread, sizeof(kmp_depnode_list_t));
147 #endif
148 
149  new_head->node = __kmp_node_ref(node);
150  new_head->next = list;
151 
152  return new_head;
153 }
154 
155 static inline void __kmp_track_dependence(kmp_depnode_t *source,
156  kmp_depnode_t *sink,
157  kmp_task_t *sink_task) {
158 #ifdef KMP_SUPPORT_GRAPH_OUTPUT
159  kmp_taskdata_t *task_source = KMP_TASK_TO_TASKDATA(source->dn.task);
160  // do not use sink->dn.task as that is only filled after the dependencies
161  // are already processed!
162  kmp_taskdata_t *task_sink = KMP_TASK_TO_TASKDATA(sink_task);
163 
164  __kmp_printf("%d(%s) -> %d(%s)\n", source->dn.id,
165  task_source->td_ident->psource, sink->dn.id,
166  task_sink->td_ident->psource);
167 #endif
168 #if OMPT_SUPPORT && OMPT_OPTIONAL
169  /* OMPT tracks dependences between task (a=source, b=sink) in which
170  task a blocks the execution of b through the ompt_new_dependence_callback
171  */
172  if (ompt_enabled.ompt_callback_task_dependence) {
173  kmp_taskdata_t *task_source = KMP_TASK_TO_TASKDATA(source->dn.task);
174  kmp_taskdata_t *task_sink = KMP_TASK_TO_TASKDATA(sink_task);
175 
176  ompt_callbacks.ompt_callback(ompt_callback_task_dependence)(
177  &(task_source->ompt_task_info.task_data),
178  &(task_sink->ompt_task_info.task_data));
179  }
180 #endif /* OMPT_SUPPORT && OMPT_OPTIONAL */
181 }
182 
183 static inline kmp_int32
184 __kmp_depnode_link_successor(kmp_int32 gtid, kmp_info_t *thread,
185  kmp_task_t *task, kmp_depnode_t *node,
186  kmp_depnode_list_t *plist) {
187  if (!plist)
188  return 0;
189  kmp_int32 npredecessors = 0;
190  // link node as successor of list elements
191  for (kmp_depnode_list_t *p = plist; p; p = p->next) {
192  kmp_depnode_t *dep = p->node;
193  if (dep->dn.task) {
194  KMP_ACQUIRE_DEPNODE(gtid, dep);
195  if (dep->dn.task) {
196  __kmp_track_dependence(dep, node, task);
197  dep->dn.successors = __kmp_add_node(thread, dep->dn.successors, node);
198  KA_TRACE(40, ("__kmp_process_deps: T#%d adding dependence from %p to "
199  "%p\n",
200  gtid, KMP_TASK_TO_TASKDATA(dep->dn.task),
201  KMP_TASK_TO_TASKDATA(task)));
202  npredecessors++;
203  }
204  KMP_RELEASE_DEPNODE(gtid, dep);
205  }
206  }
207  return npredecessors;
208 }
209 
210 static inline kmp_int32 __kmp_depnode_link_successor(kmp_int32 gtid,
211  kmp_info_t *thread,
212  kmp_task_t *task,
213  kmp_depnode_t *source,
214  kmp_depnode_t *sink) {
215  if (!sink)
216  return 0;
217  kmp_int32 npredecessors = 0;
218  if (sink->dn.task) {
219  // synchronously add source to sink' list of successors
220  KMP_ACQUIRE_DEPNODE(gtid, sink);
221  if (sink->dn.task) {
222  __kmp_track_dependence(sink, source, task);
223  sink->dn.successors = __kmp_add_node(thread, sink->dn.successors, source);
224  KA_TRACE(40, ("__kmp_process_deps: T#%d adding dependence from %p to "
225  "%p\n",
226  gtid, KMP_TASK_TO_TASKDATA(sink->dn.task),
227  KMP_TASK_TO_TASKDATA(task)));
228  npredecessors++;
229  }
230  KMP_RELEASE_DEPNODE(gtid, sink);
231  }
232  return npredecessors;
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,
239  kmp_depend_info_t *dep_list, kmp_task_t *task) {
240  KA_TRACE(30, ("__kmp_process_deps<%d>: T#%d processing %d dependencies : "
241  "dep_barrier = %d\n",
242  filter, gtid, ndeps, dep_barrier));
243 
244  kmp_info_t *thread = __kmp_threads[gtid];
245  kmp_int32 npredecessors = 0;
246  for (kmp_int32 i = 0; i < ndeps; i++) {
247  const kmp_depend_info_t *dep = &dep_list[i];
248 
249  if (filter && dep->base_addr == 0)
250  continue; // skip filtered entries
251 
252  kmp_dephash_entry_t *info =
253  __kmp_dephash_find(thread, hash, dep->base_addr);
254  kmp_depnode_t *last_out = info->last_out;
255  kmp_depnode_list_t *last_ins = info->last_ins;
256  kmp_depnode_list_t *last_mtxs = info->last_mtxs;
257 
258  if (dep->flags.out) { // out --> clean lists of ins and mtxs if any
259  if (last_ins || last_mtxs) {
260  if (info->last_flag == ENTRY_LAST_INS) { // INS were last
261  npredecessors +=
262  __kmp_depnode_link_successor(gtid, thread, task, node, last_ins);
263  } else { // MTXS were last
264  npredecessors +=
265  __kmp_depnode_link_successor(gtid, thread, task, node, last_mtxs);
266  }
267  __kmp_depnode_list_free(thread, last_ins);
268  __kmp_depnode_list_free(thread, last_mtxs);
269  info->last_ins = NULL;
270  info->last_mtxs = NULL;
271  } else {
272  npredecessors +=
273  __kmp_depnode_link_successor(gtid, thread, task, node, last_out);
274  }
275  __kmp_node_deref(thread, last_out);
276  if (dep_barrier) {
277  // if this is a sync point in the serial sequence, then the previous
278  // outputs are guaranteed to be completed after the execution of this
279  // task so the previous output nodes can be cleared.
280  info->last_out = NULL;
281  } else {
282  info->last_out = __kmp_node_ref(node);
283  }
284  } else if (dep->flags.in) {
285  // in --> link node to either last_out or last_mtxs, clean earlier deps
286  if (last_mtxs) {
287  npredecessors +=
288  __kmp_depnode_link_successor(gtid, thread, task, node, last_mtxs);
289  __kmp_node_deref(thread, last_out);
290  info->last_out = NULL;
291  if (info->last_flag == ENTRY_LAST_MTXS && last_ins) { // MTXS were last
292  // clean old INS before creating new list
293  __kmp_depnode_list_free(thread, last_ins);
294  info->last_ins = NULL;
295  }
296  } else {
297  // link node as successor of the last_out if any
298  npredecessors +=
299  __kmp_depnode_link_successor(gtid, thread, task, node, last_out);
300  }
301  info->last_flag = ENTRY_LAST_INS;
302  info->last_ins = __kmp_add_node(thread, info->last_ins, node);
303  } else {
304  KMP_DEBUG_ASSERT(dep->flags.mtx == 1);
305  // mtx --> link node to either last_out or last_ins, clean earlier deps
306  if (last_ins) {
307  npredecessors +=
308  __kmp_depnode_link_successor(gtid, thread, task, node, last_ins);
309  __kmp_node_deref(thread, last_out);
310  info->last_out = NULL;
311  if (info->last_flag == ENTRY_LAST_INS && last_mtxs) { // INS were last
312  // clean old MTXS before creating new list
313  __kmp_depnode_list_free(thread, last_mtxs);
314  info->last_mtxs = NULL;
315  }
316  } else {
317  // link node as successor of the last_out if any
318  npredecessors +=
319  __kmp_depnode_link_successor(gtid, thread, task, node, last_out);
320  }
321  info->last_flag = ENTRY_LAST_MTXS;
322  info->last_mtxs = __kmp_add_node(thread, info->last_mtxs, node);
323  if (info->mtx_lock == NULL) {
324  info->mtx_lock = (kmp_lock_t *)__kmp_allocate(sizeof(kmp_lock_t));
325  __kmp_init_lock(info->mtx_lock);
326  }
327  KMP_DEBUG_ASSERT(node->dn.mtx_num_locks < MAX_MTX_DEPS);
328  kmp_int32 m;
329  // Save lock in node's array
330  for (m = 0; m < MAX_MTX_DEPS; ++m) {
331  // sort pointers in decreasing order to avoid potential livelock
332  if (node->dn.mtx_locks[m] < info->mtx_lock) {
333  KMP_DEBUG_ASSERT(node->dn.mtx_locks[node->dn.mtx_num_locks] == NULL);
334  for (int n = node->dn.mtx_num_locks; n > m; --n) {
335  // shift right all lesser non-NULL pointers
336  KMP_DEBUG_ASSERT(node->dn.mtx_locks[n - 1] != NULL);
337  node->dn.mtx_locks[n] = node->dn.mtx_locks[n - 1];
338  }
339  node->dn.mtx_locks[m] = info->mtx_lock;
340  break;
341  }
342  }
343  KMP_DEBUG_ASSERT(m < MAX_MTX_DEPS); // must break from loop
344  node->dn.mtx_num_locks++;
345  }
346  }
347  KA_TRACE(30, ("__kmp_process_deps<%d>: T#%d found %d predecessors\n", filter,
348  gtid, npredecessors));
349  return npredecessors;
350 }
351 
352 #define NO_DEP_BARRIER (false)
353 #define DEP_BARRIER (true)
354 
355 // returns true if the task has any outstanding dependence
356 static bool __kmp_check_deps(kmp_int32 gtid, kmp_depnode_t *node,
357  kmp_task_t *task, kmp_dephash_t *hash,
358  bool dep_barrier, kmp_int32 ndeps,
359  kmp_depend_info_t *dep_list,
360  kmp_int32 ndeps_noalias,
361  kmp_depend_info_t *noalias_dep_list) {
362  int i, n_mtxs = 0;
363 #if KMP_DEBUG
364  kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
365 #endif
366  KA_TRACE(20, ("__kmp_check_deps: T#%d checking dependencies for task %p : %d "
367  "possibly aliased dependencies, %d non-aliased depedencies : "
368  "dep_barrier=%d .\n",
369  gtid, taskdata, ndeps, ndeps_noalias, dep_barrier));
370 
371  // Filter deps in dep_list
372  // TODO: Different algorithm for large dep_list ( > 10 ? )
373  for (i = 0; i < ndeps; i++) {
374  if (dep_list[i].base_addr != 0) {
375  for (int j = i + 1; j < ndeps; j++) {
376  if (dep_list[i].base_addr == dep_list[j].base_addr) {
377  dep_list[i].flags.in |= dep_list[j].flags.in;
378  dep_list[i].flags.out |=
379  (dep_list[j].flags.out ||
380  (dep_list[i].flags.in && dep_list[j].flags.mtx) ||
381  (dep_list[i].flags.mtx && dep_list[j].flags.in));
382  dep_list[i].flags.mtx =
383  dep_list[i].flags.mtx | dep_list[j].flags.mtx &&
384  !dep_list[i].flags.out;
385  dep_list[j].base_addr = 0; // Mark j element as void
386  }
387  }
388  if (dep_list[i].flags.mtx) {
389  // limit number of mtx deps to MAX_MTX_DEPS per node
390  if (n_mtxs < MAX_MTX_DEPS && task != NULL) {
391  ++n_mtxs;
392  } else {
393  dep_list[i].flags.in = 1; // downgrade mutexinoutset to inout
394  dep_list[i].flags.out = 1;
395  dep_list[i].flags.mtx = 0;
396  }
397  }
398  }
399  }
400 
401  // doesn't need to be atomic as no other thread is going to be accessing this
402  // node just yet.
403  // npredecessors is set -1 to ensure that none of the releasing tasks queues
404  // this task before we have finished processing all the dependencies
405  node->dn.npredecessors = -1;
406 
407  // used to pack all npredecessors additions into a single atomic operation at
408  // the end
409  int npredecessors;
410 
411  npredecessors = __kmp_process_deps<true>(gtid, node, hash, dep_barrier, ndeps,
412  dep_list, task);
413  npredecessors += __kmp_process_deps<false>(
414  gtid, node, hash, dep_barrier, ndeps_noalias, noalias_dep_list, task);
415 
416  node->dn.task = task;
417  KMP_MB();
418 
419  // Account for our initial fake value
420  npredecessors++;
421 
422  // Update predecessors and obtain current value to check if there are still
423  // any outstandig dependences (some tasks may have finished while we processed
424  // the dependences)
425  npredecessors =
426  node->dn.npredecessors.fetch_add(npredecessors) + npredecessors;
427 
428  KA_TRACE(20, ("__kmp_check_deps: T#%d found %d predecessors for task %p \n",
429  gtid, npredecessors, taskdata));
430 
431  // beyond this point the task could be queued (and executed) by a releasing
432  // task...
433  return npredecessors > 0 ? true : false;
434 }
435 
452 kmp_int32 __kmpc_omp_task_with_deps(ident_t *loc_ref, kmp_int32 gtid,
453  kmp_task_t *new_task, kmp_int32 ndeps,
454  kmp_depend_info_t *dep_list,
455  kmp_int32 ndeps_noalias,
456  kmp_depend_info_t *noalias_dep_list) {
457 
458  kmp_taskdata_t *new_taskdata = KMP_TASK_TO_TASKDATA(new_task);
459  KA_TRACE(10, ("__kmpc_omp_task_with_deps(enter): T#%d loc=%p task=%p\n", gtid,
460  loc_ref, new_taskdata));
461 
462  kmp_info_t *thread = __kmp_threads[gtid];
463  kmp_taskdata_t *current_task = thread->th.th_current_task;
464 
465 #if OMPT_SUPPORT
466  if (ompt_enabled.enabled) {
467  OMPT_STORE_RETURN_ADDRESS(gtid);
468  if (!current_task->ompt_task_info.frame.enter_frame.ptr)
469  current_task->ompt_task_info.frame.enter_frame.ptr =
470  OMPT_GET_FRAME_ADDRESS(0);
471  if (ompt_enabled.ompt_callback_task_create) {
472  ompt_data_t task_data = ompt_data_none;
473  ompt_callbacks.ompt_callback(ompt_callback_task_create)(
474  current_task ? &(current_task->ompt_task_info.task_data) : &task_data,
475  current_task ? &(current_task->ompt_task_info.frame) : NULL,
476  &(new_taskdata->ompt_task_info.task_data),
477  ompt_task_explicit | TASK_TYPE_DETAILS_FORMAT(new_taskdata), 1,
478  OMPT_LOAD_RETURN_ADDRESS(gtid));
479  }
480 
481  new_taskdata->ompt_task_info.frame.enter_frame.ptr = OMPT_GET_FRAME_ADDRESS(0);
482  }
483 
484 #if OMPT_OPTIONAL
485  /* OMPT grab all dependences if requested by the tool */
486  if (ndeps + ndeps_noalias > 0 &&
487  ompt_enabled.ompt_callback_dependences) {
488  kmp_int32 i;
489 
490  new_taskdata->ompt_task_info.ndeps = ndeps + ndeps_noalias;
491  new_taskdata->ompt_task_info.deps =
492  (ompt_dependence_t *)KMP_OMPT_DEPS_ALLOC(
493  thread, (ndeps + ndeps_noalias) * sizeof(ompt_dependence_t));
494 
495  KMP_ASSERT(new_taskdata->ompt_task_info.deps != NULL);
496 
497  for (i = 0; i < ndeps; i++) {
498  new_taskdata->ompt_task_info.deps[i].variable.ptr =
499  (void *)dep_list[i].base_addr;
500  if (dep_list[i].flags.in && dep_list[i].flags.out)
501  new_taskdata->ompt_task_info.deps[i].dependence_type =
502  ompt_dependence_type_inout;
503  else if (dep_list[i].flags.out)
504  new_taskdata->ompt_task_info.deps[i].dependence_type =
505  ompt_dependence_type_out;
506  else if (dep_list[i].flags.in)
507  new_taskdata->ompt_task_info.deps[i].dependence_type =
508  ompt_dependence_type_in;
509  }
510  for (i = 0; i < ndeps_noalias; i++) {
511  new_taskdata->ompt_task_info.deps[ndeps + i].variable.ptr =
512  (void *)noalias_dep_list[i].base_addr;
513  if (noalias_dep_list[i].flags.in && noalias_dep_list[i].flags.out)
514  new_taskdata->ompt_task_info.deps[ndeps + i].dependence_type =
515  ompt_dependence_type_inout;
516  else if (noalias_dep_list[i].flags.out)
517  new_taskdata->ompt_task_info.deps[ndeps + i].dependence_type =
518  ompt_dependence_type_out;
519  else if (noalias_dep_list[i].flags.in)
520  new_taskdata->ompt_task_info.deps[ndeps + i].dependence_type =
521  ompt_dependence_type_in;
522  }
523  ompt_callbacks.ompt_callback(ompt_callback_dependences)(
524  &(new_taskdata->ompt_task_info.task_data),
525  new_taskdata->ompt_task_info.deps, new_taskdata->ompt_task_info.ndeps);
526  /* We can now free the allocated memory for the dependencies */
527  /* For OMPD we might want to delay the free until task_end */
528  KMP_OMPT_DEPS_FREE(thread, new_taskdata->ompt_task_info.deps);
529  new_taskdata->ompt_task_info.deps = NULL;
530  new_taskdata->ompt_task_info.ndeps = 0;
531  }
532 #endif /* OMPT_OPTIONAL */
533 #endif /* OMPT_SUPPORT */
534 
535  bool serial = current_task->td_flags.team_serial ||
536  current_task->td_flags.tasking_ser ||
537  current_task->td_flags.final;
538 #if OMP_45_ENABLED
539  kmp_task_team_t *task_team = thread->th.th_task_team;
540  serial = serial && !(task_team && task_team->tt.tt_found_proxy_tasks);
541 #endif
542 
543  if (!serial && (ndeps > 0 || ndeps_noalias > 0)) {
544  /* if no dependencies have been tracked yet, create the dependence hash */
545  if (current_task->td_dephash == NULL)
546  current_task->td_dephash = __kmp_dephash_create(thread, current_task);
547 
548 #if USE_FAST_MEMORY
549  kmp_depnode_t *node =
550  (kmp_depnode_t *)__kmp_fast_allocate(thread, sizeof(kmp_depnode_t));
551 #else
552  kmp_depnode_t *node =
553  (kmp_depnode_t *)__kmp_thread_malloc(thread, sizeof(kmp_depnode_t));
554 #endif
555 
556  __kmp_init_node(node);
557  new_taskdata->td_depnode = node;
558 
559  if (__kmp_check_deps(gtid, node, new_task, current_task->td_dephash,
560  NO_DEP_BARRIER, ndeps, dep_list, ndeps_noalias,
561  noalias_dep_list)) {
562  KA_TRACE(10, ("__kmpc_omp_task_with_deps(exit): T#%d task had blocking "
563  "dependencies: "
564  "loc=%p task=%p, return: TASK_CURRENT_NOT_QUEUED\n",
565  gtid, loc_ref, new_taskdata));
566 #if OMPT_SUPPORT
567  if (ompt_enabled.enabled) {
568  current_task->ompt_task_info.frame.enter_frame = ompt_data_none;
569  }
570 #endif
571  return TASK_CURRENT_NOT_QUEUED;
572  }
573  } else {
574  KA_TRACE(10, ("__kmpc_omp_task_with_deps(exit): T#%d ignored dependencies "
575  "for task (serialized)"
576  "loc=%p task=%p\n",
577  gtid, loc_ref, new_taskdata));
578  }
579 
580  KA_TRACE(10, ("__kmpc_omp_task_with_deps(exit): T#%d task had no blocking "
581  "dependencies : "
582  "loc=%p task=%p, transferring to __kmp_omp_task\n",
583  gtid, loc_ref, new_taskdata));
584 
585  kmp_int32 ret = __kmp_omp_task(gtid, new_task, true);
586 #if OMPT_SUPPORT
587  if (ompt_enabled.enabled) {
588  current_task->ompt_task_info.frame.enter_frame = ompt_data_none;
589  }
590 #endif
591  return ret;
592 }
593 
605 void __kmpc_omp_wait_deps(ident_t *loc_ref, kmp_int32 gtid, kmp_int32 ndeps,
606  kmp_depend_info_t *dep_list, kmp_int32 ndeps_noalias,
607  kmp_depend_info_t *noalias_dep_list) {
608  KA_TRACE(10, ("__kmpc_omp_wait_deps(enter): T#%d loc=%p\n", gtid, loc_ref));
609 
610  if (ndeps == 0 && ndeps_noalias == 0) {
611  KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d has no dependencies to "
612  "wait upon : loc=%p\n",
613  gtid, loc_ref));
614  return;
615  }
616 
617  kmp_info_t *thread = __kmp_threads[gtid];
618  kmp_taskdata_t *current_task = thread->th.th_current_task;
619 
620  // We can return immediately as:
621  // - dependences are not computed in serial teams (except with proxy tasks)
622  // - if the dephash is not yet created it means we have nothing to wait for
623  bool ignore = current_task->td_flags.team_serial ||
624  current_task->td_flags.tasking_ser ||
625  current_task->td_flags.final;
626 #if OMP_45_ENABLED
627  ignore = ignore && thread->th.th_task_team != NULL &&
628  thread->th.th_task_team->tt.tt_found_proxy_tasks == FALSE;
629 #endif
630  ignore = ignore || current_task->td_dephash == NULL;
631 
632  if (ignore) {
633  KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d has no blocking "
634  "dependencies : loc=%p\n",
635  gtid, loc_ref));
636  return;
637  }
638 
639  kmp_depnode_t node = {0};
640  __kmp_init_node(&node);
641 
642  if (!__kmp_check_deps(gtid, &node, NULL, current_task->td_dephash,
643  DEP_BARRIER, ndeps, dep_list, ndeps_noalias,
644  noalias_dep_list)) {
645  KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d has no blocking "
646  "dependencies : loc=%p\n",
647  gtid, loc_ref));
648  return;
649  }
650 
651  int thread_finished = FALSE;
652  kmp_flag_32 flag((std::atomic<kmp_uint32> *)&node.dn.npredecessors, 0U);
653  while (node.dn.npredecessors > 0) {
654  flag.execute_tasks(thread, gtid, FALSE,
655  &thread_finished USE_ITT_BUILD_ARG(NULL),
656  __kmp_task_stealing_constraint);
657  }
658 
659  KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d finished waiting : loc=%p\n",
660  gtid, loc_ref));
661 }
662 
663 #endif /* OMP_40_ENABLED */
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)
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)
Definition: kmp.h:223