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 // TODO: Improve memory allocation? keep a list of pre-allocated structures?
24 // 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
29 // runtime locks
30 // TODO: Any ITT support needed?
31 
32 #ifdef KMP_SUPPORT_GRAPH_OUTPUT
33 static std::atomic<kmp_int32> kmp_node_id_seed = ATOMIC_VAR_INIT(0);
34 #endif
35 
36 static void __kmp_init_node(kmp_depnode_t *node) {
37  node->dn.successors = NULL;
38  node->dn.task = NULL; // will point to the rigth task
39  // once dependences have been processed
40  for (int i = 0; i < MAX_MTX_DEPS; ++i)
41  node->dn.mtx_locks[i] = NULL;
42  node->dn.mtx_num_locks = 0;
43  __kmp_init_lock(&node->dn.lock);
44  KMP_ATOMIC_ST_RLX(&node->dn.nrefs, 1); // init creates the first reference
45 #ifdef KMP_SUPPORT_GRAPH_OUTPUT
46  node->dn.id = KMP_ATOMIC_INC(&kmp_node_id_seed);
47 #endif
48 }
49 
50 static inline kmp_depnode_t *__kmp_node_ref(kmp_depnode_t *node) {
51  KMP_ATOMIC_INC(&node->dn.nrefs);
52  return node;
53 }
54 
55 enum { KMP_DEPHASH_OTHER_SIZE = 97, KMP_DEPHASH_MASTER_SIZE = 997 };
56 
57 size_t sizes[] = { 997, 2003, 4001, 8191, 16001, 32003, 64007, 131071, 270029 };
58 const size_t MAX_GEN = 8;
59 
60 static inline kmp_int32 __kmp_dephash_hash(kmp_intptr_t addr, size_t hsize) {
61  // TODO alternate to try: set = (((Addr64)(addrUsefulBits * 9.618)) %
62  // m_num_sets );
63  return ((addr >> 6) ^ (addr >> 2)) % hsize;
64 }
65 
66 static kmp_dephash_t *__kmp_dephash_extend(kmp_info_t *thread,
67  kmp_dephash_t *current_dephash) {
68  kmp_dephash_t *h;
69 
70  size_t gen = current_dephash->generation + 1;
71  if (gen >= MAX_GEN)
72  return current_dephash;
73  size_t new_size = sizes[gen];
74 
75  kmp_int32 size_to_allocate =
76  new_size * sizeof(kmp_dephash_entry_t *) + sizeof(kmp_dephash_t);
77 
78 #if USE_FAST_MEMORY
79  h = (kmp_dephash_t *)__kmp_fast_allocate(thread, size_to_allocate);
80 #else
81  h = (kmp_dephash_t *)__kmp_thread_malloc(thread, size_to_allocate);
82 #endif
83 
84  h->size = new_size;
85  h->nelements = current_dephash->nelements;
86  h->buckets = (kmp_dephash_entry **)(h + 1);
87  h->generation = gen;
88  h->nconflicts = 0;
89  // insert existing elements in the new table
90  for (size_t i = 0; i < current_dephash->size; i++) {
91  kmp_dephash_entry_t *next, *entry;
92  for (entry = current_dephash->buckets[i]; entry; entry = next) {
93  next = entry->next_in_bucket;
94  // Compute the new hash using the new size, and insert the entry in
95  // the new bucket.
96  kmp_int32 new_bucket = __kmp_dephash_hash(entry->addr, h->size);
97  entry->next_in_bucket = h->buckets[new_bucket];
98  if (entry->next_in_bucket) {
99  h->nconflicts++;
100  }
101  h->buckets[new_bucket] = entry;
102  }
103  }
104 
105  // Free old hash table
106 #if USE_FAST_MEMORY
107  __kmp_fast_free(thread, current_dephash);
108 #else
109  __kmp_thread_free(thread, current_dephash);
110 #endif
111 
112  return h;
113 }
114 
115 static kmp_dephash_t *__kmp_dephash_create(kmp_info_t *thread,
116  kmp_taskdata_t *current_task) {
117  kmp_dephash_t *h;
118 
119  size_t h_size;
120 
121  if (current_task->td_flags.tasktype == TASK_IMPLICIT)
122  h_size = KMP_DEPHASH_MASTER_SIZE;
123  else
124  h_size = KMP_DEPHASH_OTHER_SIZE;
125 
126  kmp_int32 size =
127  h_size * sizeof(kmp_dephash_entry_t *) + sizeof(kmp_dephash_t);
128 
129 #if USE_FAST_MEMORY
130  h = (kmp_dephash_t *)__kmp_fast_allocate(thread, size);
131 #else
132  h = (kmp_dephash_t *)__kmp_thread_malloc(thread, size);
133 #endif
134  h->size = h_size;
135 
136  h->generation = 0;
137  h->nelements = 0;
138  h->nconflicts = 0;
139  h->buckets = (kmp_dephash_entry **)(h + 1);
140 
141  for (size_t i = 0; i < h_size; i++)
142  h->buckets[i] = 0;
143 
144  return h;
145 }
146 
147 #define ENTRY_LAST_INS 0
148 #define ENTRY_LAST_MTXS 1
149 
150 static kmp_dephash_entry *
151 __kmp_dephash_find(kmp_info_t *thread, kmp_dephash_t **hash, kmp_intptr_t addr) {
152  kmp_dephash_t *h = *hash;
153  if (h->nelements != 0
154  && h->nconflicts/h->size >= 1) {
155  *hash = __kmp_dephash_extend(thread, h);
156  h = *hash;
157  }
158  kmp_int32 bucket = __kmp_dephash_hash(addr, h->size);
159 
160  kmp_dephash_entry_t *entry;
161  for (entry = h->buckets[bucket]; entry; entry = entry->next_in_bucket)
162  if (entry->addr == addr)
163  break;
164 
165  if (entry == NULL) {
166 // create entry. This is only done by one thread so no locking required
167 #if USE_FAST_MEMORY
168  entry = (kmp_dephash_entry_t *)__kmp_fast_allocate(
169  thread, sizeof(kmp_dephash_entry_t));
170 #else
171  entry = (kmp_dephash_entry_t *)__kmp_thread_malloc(
172  thread, sizeof(kmp_dephash_entry_t));
173 #endif
174  entry->addr = addr;
175  entry->last_out = NULL;
176  entry->last_ins = NULL;
177  entry->last_mtxs = NULL;
178  entry->last_flag = ENTRY_LAST_INS;
179  entry->mtx_lock = NULL;
180  entry->next_in_bucket = h->buckets[bucket];
181  h->buckets[bucket] = entry;
182  h->nelements++;
183  if (entry->next_in_bucket)
184  h->nconflicts++;
185  }
186  return entry;
187 }
188 
189 static kmp_depnode_list_t *__kmp_add_node(kmp_info_t *thread,
190  kmp_depnode_list_t *list,
191  kmp_depnode_t *node) {
192  kmp_depnode_list_t *new_head;
193 
194 #if USE_FAST_MEMORY
195  new_head = (kmp_depnode_list_t *)__kmp_fast_allocate(
196  thread, sizeof(kmp_depnode_list_t));
197 #else
198  new_head = (kmp_depnode_list_t *)__kmp_thread_malloc(
199  thread, sizeof(kmp_depnode_list_t));
200 #endif
201 
202  new_head->node = __kmp_node_ref(node);
203  new_head->next = list;
204 
205  return new_head;
206 }
207 
208 static inline void __kmp_track_dependence(kmp_depnode_t *source,
209  kmp_depnode_t *sink,
210  kmp_task_t *sink_task) {
211 #ifdef KMP_SUPPORT_GRAPH_OUTPUT
212  kmp_taskdata_t *task_source = KMP_TASK_TO_TASKDATA(source->dn.task);
213  // do not use sink->dn.task as that is only filled after the dependencies
214  // are already processed!
215  kmp_taskdata_t *task_sink = KMP_TASK_TO_TASKDATA(sink_task);
216 
217  __kmp_printf("%d(%s) -> %d(%s)\n", source->dn.id,
218  task_source->td_ident->psource, sink->dn.id,
219  task_sink->td_ident->psource);
220 #endif
221 #if OMPT_SUPPORT && OMPT_OPTIONAL
222  /* OMPT tracks dependences between task (a=source, b=sink) in which
223  task a blocks the execution of b through the ompt_new_dependence_callback
224  */
225  if (ompt_enabled.ompt_callback_task_dependence) {
226  kmp_taskdata_t *task_source = KMP_TASK_TO_TASKDATA(source->dn.task);
227  kmp_taskdata_t *task_sink = KMP_TASK_TO_TASKDATA(sink_task);
228 
229  ompt_callbacks.ompt_callback(ompt_callback_task_dependence)(
230  &(task_source->ompt_task_info.task_data),
231  &(task_sink->ompt_task_info.task_data));
232  }
233 #endif /* OMPT_SUPPORT && OMPT_OPTIONAL */
234 }
235 
236 static inline kmp_int32
237 __kmp_depnode_link_successor(kmp_int32 gtid, kmp_info_t *thread,
238  kmp_task_t *task, kmp_depnode_t *node,
239  kmp_depnode_list_t *plist) {
240  if (!plist)
241  return 0;
242  kmp_int32 npredecessors = 0;
243  // link node as successor of list elements
244  for (kmp_depnode_list_t *p = plist; p; p = p->next) {
245  kmp_depnode_t *dep = p->node;
246  if (dep->dn.task) {
247  KMP_ACQUIRE_DEPNODE(gtid, dep);
248  if (dep->dn.task) {
249  __kmp_track_dependence(dep, node, task);
250  dep->dn.successors = __kmp_add_node(thread, dep->dn.successors, node);
251  KA_TRACE(40, ("__kmp_process_deps: T#%d adding dependence from %p to "
252  "%p\n",
253  gtid, KMP_TASK_TO_TASKDATA(dep->dn.task),
254  KMP_TASK_TO_TASKDATA(task)));
255  npredecessors++;
256  }
257  KMP_RELEASE_DEPNODE(gtid, dep);
258  }
259  }
260  return npredecessors;
261 }
262 
263 static inline kmp_int32 __kmp_depnode_link_successor(kmp_int32 gtid,
264  kmp_info_t *thread,
265  kmp_task_t *task,
266  kmp_depnode_t *source,
267  kmp_depnode_t *sink) {
268  if (!sink)
269  return 0;
270  kmp_int32 npredecessors = 0;
271  if (sink->dn.task) {
272  // synchronously add source to sink' list of successors
273  KMP_ACQUIRE_DEPNODE(gtid, sink);
274  if (sink->dn.task) {
275  __kmp_track_dependence(sink, source, task);
276  sink->dn.successors = __kmp_add_node(thread, sink->dn.successors, source);
277  KA_TRACE(40, ("__kmp_process_deps: T#%d adding dependence from %p to "
278  "%p\n",
279  gtid, KMP_TASK_TO_TASKDATA(sink->dn.task),
280  KMP_TASK_TO_TASKDATA(task)));
281  npredecessors++;
282  }
283  KMP_RELEASE_DEPNODE(gtid, sink);
284  }
285  return npredecessors;
286 }
287 
288 template <bool filter>
289 static inline kmp_int32
290 __kmp_process_deps(kmp_int32 gtid, kmp_depnode_t *node, kmp_dephash_t **hash,
291  bool dep_barrier, kmp_int32 ndeps,
292  kmp_depend_info_t *dep_list, kmp_task_t *task) {
293  KA_TRACE(30, ("__kmp_process_deps<%d>: T#%d processing %d dependencies : "
294  "dep_barrier = %d\n",
295  filter, gtid, ndeps, dep_barrier));
296 
297  kmp_info_t *thread = __kmp_threads[gtid];
298  kmp_int32 npredecessors = 0;
299  for (kmp_int32 i = 0; i < ndeps; i++) {
300  const kmp_depend_info_t *dep = &dep_list[i];
301 
302  if (filter && dep->base_addr == 0)
303  continue; // skip filtered entries
304 
305  kmp_dephash_entry_t *info =
306  __kmp_dephash_find(thread, hash, dep->base_addr);
307  kmp_depnode_t *last_out = info->last_out;
308  kmp_depnode_list_t *last_ins = info->last_ins;
309  kmp_depnode_list_t *last_mtxs = info->last_mtxs;
310 
311  if (dep->flags.out) { // out --> clean lists of ins and mtxs if any
312  if (last_ins || last_mtxs) {
313  if (info->last_flag == ENTRY_LAST_INS) { // INS were last
314  npredecessors +=
315  __kmp_depnode_link_successor(gtid, thread, task, node, last_ins);
316  } else { // MTXS were last
317  npredecessors +=
318  __kmp_depnode_link_successor(gtid, thread, task, node, last_mtxs);
319  }
320  __kmp_depnode_list_free(thread, last_ins);
321  __kmp_depnode_list_free(thread, last_mtxs);
322  info->last_ins = NULL;
323  info->last_mtxs = NULL;
324  } else {
325  npredecessors +=
326  __kmp_depnode_link_successor(gtid, thread, task, node, last_out);
327  }
328  __kmp_node_deref(thread, last_out);
329  if (dep_barrier) {
330  // if this is a sync point in the serial sequence, then the previous
331  // outputs are guaranteed to be completed after the execution of this
332  // task so the previous output nodes can be cleared.
333  info->last_out = NULL;
334  } else {
335  info->last_out = __kmp_node_ref(node);
336  }
337  } else if (dep->flags.in) {
338  // in --> link node to either last_out or last_mtxs, clean earlier deps
339  if (last_mtxs) {
340  npredecessors +=
341  __kmp_depnode_link_successor(gtid, thread, task, node, last_mtxs);
342  __kmp_node_deref(thread, last_out);
343  info->last_out = NULL;
344  if (info->last_flag == ENTRY_LAST_MTXS && last_ins) { // MTXS were last
345  // clean old INS before creating new list
346  __kmp_depnode_list_free(thread, last_ins);
347  info->last_ins = NULL;
348  }
349  } else {
350  // link node as successor of the last_out if any
351  npredecessors +=
352  __kmp_depnode_link_successor(gtid, thread, task, node, last_out);
353  }
354  info->last_flag = ENTRY_LAST_INS;
355  info->last_ins = __kmp_add_node(thread, info->last_ins, node);
356  } else {
357  KMP_DEBUG_ASSERT(dep->flags.mtx == 1);
358  // mtx --> link node to either last_out or last_ins, clean earlier deps
359  if (last_ins) {
360  npredecessors +=
361  __kmp_depnode_link_successor(gtid, thread, task, node, last_ins);
362  __kmp_node_deref(thread, last_out);
363  info->last_out = NULL;
364  if (info->last_flag == ENTRY_LAST_INS && last_mtxs) { // INS were last
365  // clean old MTXS before creating new list
366  __kmp_depnode_list_free(thread, last_mtxs);
367  info->last_mtxs = NULL;
368  }
369  } else {
370  // link node as successor of the last_out if any
371  npredecessors +=
372  __kmp_depnode_link_successor(gtid, thread, task, node, last_out);
373  }
374  info->last_flag = ENTRY_LAST_MTXS;
375  info->last_mtxs = __kmp_add_node(thread, info->last_mtxs, node);
376  if (info->mtx_lock == NULL) {
377  info->mtx_lock = (kmp_lock_t *)__kmp_allocate(sizeof(kmp_lock_t));
378  __kmp_init_lock(info->mtx_lock);
379  }
380  KMP_DEBUG_ASSERT(node->dn.mtx_num_locks < MAX_MTX_DEPS);
381  kmp_int32 m;
382  // Save lock in node's array
383  for (m = 0; m < MAX_MTX_DEPS; ++m) {
384  // sort pointers in decreasing order to avoid potential livelock
385  if (node->dn.mtx_locks[m] < info->mtx_lock) {
386  KMP_DEBUG_ASSERT(node->dn.mtx_locks[node->dn.mtx_num_locks] == NULL);
387  for (int n = node->dn.mtx_num_locks; n > m; --n) {
388  // shift right all lesser non-NULL pointers
389  KMP_DEBUG_ASSERT(node->dn.mtx_locks[n - 1] != NULL);
390  node->dn.mtx_locks[n] = node->dn.mtx_locks[n - 1];
391  }
392  node->dn.mtx_locks[m] = info->mtx_lock;
393  break;
394  }
395  }
396  KMP_DEBUG_ASSERT(m < MAX_MTX_DEPS); // must break from loop
397  node->dn.mtx_num_locks++;
398  }
399  }
400  KA_TRACE(30, ("__kmp_process_deps<%d>: T#%d found %d predecessors\n", filter,
401  gtid, npredecessors));
402  return npredecessors;
403 }
404 
405 #define NO_DEP_BARRIER (false)
406 #define DEP_BARRIER (true)
407 
408 // returns true if the task has any outstanding dependence
409 static bool __kmp_check_deps(kmp_int32 gtid, kmp_depnode_t *node,
410  kmp_task_t *task, kmp_dephash_t **hash,
411  bool dep_barrier, kmp_int32 ndeps,
412  kmp_depend_info_t *dep_list,
413  kmp_int32 ndeps_noalias,
414  kmp_depend_info_t *noalias_dep_list) {
415  int i, n_mtxs = 0;
416 #if KMP_DEBUG
417  kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
418 #endif
419  KA_TRACE(20, ("__kmp_check_deps: T#%d checking dependencies for task %p : %d "
420  "possibly aliased dependencies, %d non-aliased dependencies : "
421  "dep_barrier=%d .\n",
422  gtid, taskdata, ndeps, ndeps_noalias, dep_barrier));
423 
424  // Filter deps in dep_list
425  // TODO: Different algorithm for large dep_list ( > 10 ? )
426  for (i = 0; i < ndeps; i++) {
427  if (dep_list[i].base_addr != 0) {
428  for (int j = i + 1; j < ndeps; j++) {
429  if (dep_list[i].base_addr == dep_list[j].base_addr) {
430  dep_list[i].flags.in |= dep_list[j].flags.in;
431  dep_list[i].flags.out |=
432  (dep_list[j].flags.out ||
433  (dep_list[i].flags.in && dep_list[j].flags.mtx) ||
434  (dep_list[i].flags.mtx && dep_list[j].flags.in));
435  dep_list[i].flags.mtx =
436  dep_list[i].flags.mtx | dep_list[j].flags.mtx &&
437  !dep_list[i].flags.out;
438  dep_list[j].base_addr = 0; // Mark j element as void
439  }
440  }
441  if (dep_list[i].flags.mtx) {
442  // limit number of mtx deps to MAX_MTX_DEPS per node
443  if (n_mtxs < MAX_MTX_DEPS && task != NULL) {
444  ++n_mtxs;
445  } else {
446  dep_list[i].flags.in = 1; // downgrade mutexinoutset to inout
447  dep_list[i].flags.out = 1;
448  dep_list[i].flags.mtx = 0;
449  }
450  }
451  }
452  }
453 
454  // doesn't need to be atomic as no other thread is going to be accessing this
455  // node just yet.
456  // npredecessors is set -1 to ensure that none of the releasing tasks queues
457  // this task before we have finished processing all the dependencies
458  node->dn.npredecessors = -1;
459 
460  // used to pack all npredecessors additions into a single atomic operation at
461  // the end
462  int npredecessors;
463 
464  npredecessors = __kmp_process_deps<true>(gtid, node, hash, dep_barrier, ndeps,
465  dep_list, task);
466  npredecessors += __kmp_process_deps<false>(
467  gtid, node, hash, dep_barrier, ndeps_noalias, noalias_dep_list, task);
468 
469  node->dn.task = task;
470  KMP_MB();
471 
472  // Account for our initial fake value
473  npredecessors++;
474 
475  // Update predecessors and obtain current value to check if there are still
476  // any outstandig dependences (some tasks may have finished while we processed
477  // the dependences)
478  npredecessors =
479  node->dn.npredecessors.fetch_add(npredecessors) + npredecessors;
480 
481  KA_TRACE(20, ("__kmp_check_deps: T#%d found %d predecessors for task %p \n",
482  gtid, npredecessors, taskdata));
483 
484  // beyond this point the task could be queued (and executed) by a releasing
485  // task...
486  return npredecessors > 0 ? true : false;
487 }
488 
505 kmp_int32 __kmpc_omp_task_with_deps(ident_t *loc_ref, kmp_int32 gtid,
506  kmp_task_t *new_task, kmp_int32 ndeps,
507  kmp_depend_info_t *dep_list,
508  kmp_int32 ndeps_noalias,
509  kmp_depend_info_t *noalias_dep_list) {
510 
511  kmp_taskdata_t *new_taskdata = KMP_TASK_TO_TASKDATA(new_task);
512  KA_TRACE(10, ("__kmpc_omp_task_with_deps(enter): T#%d loc=%p task=%p\n", gtid,
513  loc_ref, new_taskdata));
514 
515  kmp_info_t *thread = __kmp_threads[gtid];
516  kmp_taskdata_t *current_task = thread->th.th_current_task;
517 
518 #if OMPT_SUPPORT
519  if (ompt_enabled.enabled) {
520  OMPT_STORE_RETURN_ADDRESS(gtid);
521  if (!current_task->ompt_task_info.frame.enter_frame.ptr)
522  current_task->ompt_task_info.frame.enter_frame.ptr =
523  OMPT_GET_FRAME_ADDRESS(0);
524  if (ompt_enabled.ompt_callback_task_create) {
525  ompt_data_t task_data = ompt_data_none;
526  ompt_callbacks.ompt_callback(ompt_callback_task_create)(
527  current_task ? &(current_task->ompt_task_info.task_data) : &task_data,
528  current_task ? &(current_task->ompt_task_info.frame) : NULL,
529  &(new_taskdata->ompt_task_info.task_data),
530  ompt_task_explicit | TASK_TYPE_DETAILS_FORMAT(new_taskdata), 1,
531  OMPT_LOAD_RETURN_ADDRESS(gtid));
532  }
533 
534  new_taskdata->ompt_task_info.frame.enter_frame.ptr = OMPT_GET_FRAME_ADDRESS(0);
535  }
536 
537 #if OMPT_OPTIONAL
538  /* OMPT grab all dependences if requested by the tool */
539  if (ndeps + ndeps_noalias > 0 &&
540  ompt_enabled.ompt_callback_dependences) {
541  kmp_int32 i;
542 
543  new_taskdata->ompt_task_info.ndeps = ndeps + ndeps_noalias;
544  new_taskdata->ompt_task_info.deps =
545  (ompt_dependence_t *)KMP_OMPT_DEPS_ALLOC(
546  thread, (ndeps + ndeps_noalias) * sizeof(ompt_dependence_t));
547 
548  KMP_ASSERT(new_taskdata->ompt_task_info.deps != NULL);
549 
550  for (i = 0; i < ndeps; i++) {
551  new_taskdata->ompt_task_info.deps[i].variable.ptr =
552  (void *)dep_list[i].base_addr;
553  if (dep_list[i].flags.in && dep_list[i].flags.out)
554  new_taskdata->ompt_task_info.deps[i].dependence_type =
555  ompt_dependence_type_inout;
556  else if (dep_list[i].flags.out)
557  new_taskdata->ompt_task_info.deps[i].dependence_type =
558  ompt_dependence_type_out;
559  else if (dep_list[i].flags.in)
560  new_taskdata->ompt_task_info.deps[i].dependence_type =
561  ompt_dependence_type_in;
562  }
563  for (i = 0; i < ndeps_noalias; i++) {
564  new_taskdata->ompt_task_info.deps[ndeps + i].variable.ptr =
565  (void *)noalias_dep_list[i].base_addr;
566  if (noalias_dep_list[i].flags.in && noalias_dep_list[i].flags.out)
567  new_taskdata->ompt_task_info.deps[ndeps + i].dependence_type =
568  ompt_dependence_type_inout;
569  else if (noalias_dep_list[i].flags.out)
570  new_taskdata->ompt_task_info.deps[ndeps + i].dependence_type =
571  ompt_dependence_type_out;
572  else if (noalias_dep_list[i].flags.in)
573  new_taskdata->ompt_task_info.deps[ndeps + i].dependence_type =
574  ompt_dependence_type_in;
575  }
576  ompt_callbacks.ompt_callback(ompt_callback_dependences)(
577  &(new_taskdata->ompt_task_info.task_data),
578  new_taskdata->ompt_task_info.deps, new_taskdata->ompt_task_info.ndeps);
579  /* We can now free the allocated memory for the dependencies */
580  /* For OMPD we might want to delay the free until task_end */
581  KMP_OMPT_DEPS_FREE(thread, new_taskdata->ompt_task_info.deps);
582  new_taskdata->ompt_task_info.deps = NULL;
583  new_taskdata->ompt_task_info.ndeps = 0;
584  }
585 #endif /* OMPT_OPTIONAL */
586 #endif /* OMPT_SUPPORT */
587 
588  bool serial = current_task->td_flags.team_serial ||
589  current_task->td_flags.tasking_ser ||
590  current_task->td_flags.final;
591  kmp_task_team_t *task_team = thread->th.th_task_team;
592  serial = serial && !(task_team && task_team->tt.tt_found_proxy_tasks);
593 
594  if (!serial && (ndeps > 0 || ndeps_noalias > 0)) {
595  /* if no dependencies have been tracked yet, create the dependence hash */
596  if (current_task->td_dephash == NULL)
597  current_task->td_dephash = __kmp_dephash_create(thread, current_task);
598 
599 #if USE_FAST_MEMORY
600  kmp_depnode_t *node =
601  (kmp_depnode_t *)__kmp_fast_allocate(thread, sizeof(kmp_depnode_t));
602 #else
603  kmp_depnode_t *node =
604  (kmp_depnode_t *)__kmp_thread_malloc(thread, sizeof(kmp_depnode_t));
605 #endif
606 
607  __kmp_init_node(node);
608  new_taskdata->td_depnode = node;
609 
610  if (__kmp_check_deps(gtid, node, new_task, &current_task->td_dephash,
611  NO_DEP_BARRIER, ndeps, dep_list, ndeps_noalias,
612  noalias_dep_list)) {
613  KA_TRACE(10, ("__kmpc_omp_task_with_deps(exit): T#%d task had blocking "
614  "dependencies: "
615  "loc=%p task=%p, return: TASK_CURRENT_NOT_QUEUED\n",
616  gtid, loc_ref, new_taskdata));
617 #if OMPT_SUPPORT
618  if (ompt_enabled.enabled) {
619  current_task->ompt_task_info.frame.enter_frame = ompt_data_none;
620  }
621 #endif
622  return TASK_CURRENT_NOT_QUEUED;
623  }
624  } else {
625  KA_TRACE(10, ("__kmpc_omp_task_with_deps(exit): T#%d ignored dependencies "
626  "for task (serialized)"
627  "loc=%p task=%p\n",
628  gtid, loc_ref, new_taskdata));
629  }
630 
631  KA_TRACE(10, ("__kmpc_omp_task_with_deps(exit): T#%d task had no blocking "
632  "dependencies : "
633  "loc=%p task=%p, transferring to __kmp_omp_task\n",
634  gtid, loc_ref, new_taskdata));
635 
636  kmp_int32 ret = __kmp_omp_task(gtid, new_task, true);
637 #if OMPT_SUPPORT
638  if (ompt_enabled.enabled) {
639  current_task->ompt_task_info.frame.enter_frame = ompt_data_none;
640  }
641 #endif
642  return ret;
643 }
644 
656 void __kmpc_omp_wait_deps(ident_t *loc_ref, kmp_int32 gtid, kmp_int32 ndeps,
657  kmp_depend_info_t *dep_list, kmp_int32 ndeps_noalias,
658  kmp_depend_info_t *noalias_dep_list) {
659  KA_TRACE(10, ("__kmpc_omp_wait_deps(enter): T#%d loc=%p\n", gtid, loc_ref));
660 
661  if (ndeps == 0 && ndeps_noalias == 0) {
662  KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d has no dependencies to "
663  "wait upon : loc=%p\n",
664  gtid, loc_ref));
665  return;
666  }
667 
668  kmp_info_t *thread = __kmp_threads[gtid];
669  kmp_taskdata_t *current_task = thread->th.th_current_task;
670 
671  // We can return immediately as:
672  // - dependences are not computed in serial teams (except with proxy tasks)
673  // - if the dephash is not yet created it means we have nothing to wait for
674  bool ignore = current_task->td_flags.team_serial ||
675  current_task->td_flags.tasking_ser ||
676  current_task->td_flags.final;
677  ignore = ignore && thread->th.th_task_team != NULL &&
678  thread->th.th_task_team->tt.tt_found_proxy_tasks == FALSE;
679  ignore = ignore || current_task->td_dephash == NULL;
680 
681  if (ignore) {
682  KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d has no blocking "
683  "dependencies : loc=%p\n",
684  gtid, loc_ref));
685  return;
686  }
687 
688  kmp_depnode_t node = {0};
689  __kmp_init_node(&node);
690 
691  if (!__kmp_check_deps(gtid, &node, NULL, &current_task->td_dephash,
692  DEP_BARRIER, ndeps, dep_list, ndeps_noalias,
693  noalias_dep_list)) {
694  KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d has no blocking "
695  "dependencies : loc=%p\n",
696  gtid, loc_ref));
697  return;
698  }
699 
700  int thread_finished = FALSE;
701  kmp_flag_32 flag((std::atomic<kmp_uint32> *)&node.dn.npredecessors, 0U);
702  while (node.dn.npredecessors > 0) {
703  flag.execute_tasks(thread, gtid, FALSE,
704  &thread_finished USE_ITT_BUILD_ARG(NULL),
705  __kmp_task_stealing_constraint);
706  }
707 
708  KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d finished waiting : loc=%p\n",
709  gtid, loc_ref));
710 }
__kmpc_omp_task_with_deps
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_taskdeps.cpp:505
ident
Definition: kmp.h:222
__kmpc_omp_wait_deps
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)
Definition: kmp_taskdeps.cpp:656