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 right 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 size_t __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  size_t 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 
90  // make sure buckets are properly initialized
91  for (size_t i = 0; i < new_size; i++) {
92  h->buckets[i] = NULL;
93  }
94 
95  // insert existing elements in the new table
96  for (size_t i = 0; i < current_dephash->size; i++) {
97  kmp_dephash_entry_t *next, *entry;
98  for (entry = current_dephash->buckets[i]; entry; entry = next) {
99  next = entry->next_in_bucket;
100  // Compute the new hash using the new size, and insert the entry in
101  // the new bucket.
102  size_t new_bucket = __kmp_dephash_hash(entry->addr, h->size);
103  entry->next_in_bucket = h->buckets[new_bucket];
104  if (entry->next_in_bucket) {
105  h->nconflicts++;
106  }
107  h->buckets[new_bucket] = entry;
108  }
109  }
110 
111  // Free old hash table
112 #if USE_FAST_MEMORY
113  __kmp_fast_free(thread, current_dephash);
114 #else
115  __kmp_thread_free(thread, current_dephash);
116 #endif
117 
118  return h;
119 }
120 
121 static kmp_dephash_t *__kmp_dephash_create(kmp_info_t *thread,
122  kmp_taskdata_t *current_task) {
123  kmp_dephash_t *h;
124 
125  size_t h_size;
126 
127  if (current_task->td_flags.tasktype == TASK_IMPLICIT)
128  h_size = KMP_DEPHASH_MASTER_SIZE;
129  else
130  h_size = KMP_DEPHASH_OTHER_SIZE;
131 
132  size_t size = h_size * sizeof(kmp_dephash_entry_t *) + sizeof(kmp_dephash_t);
133 
134 #if USE_FAST_MEMORY
135  h = (kmp_dephash_t *)__kmp_fast_allocate(thread, size);
136 #else
137  h = (kmp_dephash_t *)__kmp_thread_malloc(thread, size);
138 #endif
139  h->size = h_size;
140 
141  h->generation = 0;
142  h->nelements = 0;
143  h->nconflicts = 0;
144  h->buckets = (kmp_dephash_entry **)(h + 1);
145 
146  for (size_t i = 0; i < h_size; i++)
147  h->buckets[i] = 0;
148 
149  return h;
150 }
151 
152 static kmp_dephash_entry *__kmp_dephash_find(kmp_info_t *thread,
153  kmp_dephash_t **hash,
154  kmp_intptr_t addr) {
155  kmp_dephash_t *h = *hash;
156  if (h->nelements != 0 && h->nconflicts / h->size >= 1) {
157  *hash = __kmp_dephash_extend(thread, h);
158  h = *hash;
159  }
160  size_t bucket = __kmp_dephash_hash(addr, h->size);
161 
162  kmp_dephash_entry_t *entry;
163  for (entry = h->buckets[bucket]; entry; entry = entry->next_in_bucket)
164  if (entry->addr == addr)
165  break;
166 
167  if (entry == NULL) {
168 // create entry. This is only done by one thread so no locking required
169 #if USE_FAST_MEMORY
170  entry = (kmp_dephash_entry_t *)__kmp_fast_allocate(
171  thread, sizeof(kmp_dephash_entry_t));
172 #else
173  entry = (kmp_dephash_entry_t *)__kmp_thread_malloc(
174  thread, sizeof(kmp_dephash_entry_t));
175 #endif
176  entry->addr = addr;
177  entry->last_out = NULL;
178  entry->last_set = NULL;
179  entry->prev_set = NULL;
180  entry->last_flag = 0;
181  entry->mtx_lock = NULL;
182  entry->next_in_bucket = h->buckets[bucket];
183  h->buckets[bucket] = entry;
184  h->nelements++;
185  if (entry->next_in_bucket)
186  h->nconflicts++;
187  }
188  return entry;
189 }
190 
191 static kmp_depnode_list_t *__kmp_add_node(kmp_info_t *thread,
192  kmp_depnode_list_t *list,
193  kmp_depnode_t *node) {
194  kmp_depnode_list_t *new_head;
195 
196 #if USE_FAST_MEMORY
197  new_head = (kmp_depnode_list_t *)__kmp_fast_allocate(
198  thread, sizeof(kmp_depnode_list_t));
199 #else
200  new_head = (kmp_depnode_list_t *)__kmp_thread_malloc(
201  thread, sizeof(kmp_depnode_list_t));
202 #endif
203 
204  new_head->node = __kmp_node_ref(node);
205  new_head->next = list;
206 
207  return new_head;
208 }
209 
210 static inline void __kmp_track_dependence(kmp_int32 gtid, kmp_depnode_t *source,
211  kmp_depnode_t *sink,
212  kmp_task_t *sink_task) {
213 #ifdef KMP_SUPPORT_GRAPH_OUTPUT
214  kmp_taskdata_t *task_source = KMP_TASK_TO_TASKDATA(source->dn.task);
215  // do not use sink->dn.task as that is only filled after the dependences
216  // are already processed!
217  kmp_taskdata_t *task_sink = KMP_TASK_TO_TASKDATA(sink_task);
218 
219  __kmp_printf("%d(%s) -> %d(%s)\n", source->dn.id,
220  task_source->td_ident->psource, sink->dn.id,
221  task_sink->td_ident->psource);
222 #endif
223 #if OMPT_SUPPORT && OMPT_OPTIONAL
224  /* OMPT tracks dependences between task (a=source, b=sink) in which
225  task a blocks the execution of b through the ompt_new_dependence_callback
226  */
227  if (ompt_enabled.ompt_callback_task_dependence) {
228  kmp_taskdata_t *task_source = KMP_TASK_TO_TASKDATA(source->dn.task);
229  ompt_data_t *sink_data;
230  if (sink_task)
231  sink_data = &(KMP_TASK_TO_TASKDATA(sink_task)->ompt_task_info.task_data);
232  else
233  sink_data = &__kmp_threads[gtid]->th.ompt_thread_info.task_data;
234 
235  ompt_callbacks.ompt_callback(ompt_callback_task_dependence)(
236  &(task_source->ompt_task_info.task_data), sink_data);
237  }
238 #endif /* OMPT_SUPPORT && OMPT_OPTIONAL */
239 }
240 
241 static inline kmp_int32
242 __kmp_depnode_link_successor(kmp_int32 gtid, kmp_info_t *thread,
243  kmp_task_t *task, kmp_depnode_t *node,
244  kmp_depnode_list_t *plist) {
245  if (!plist)
246  return 0;
247  kmp_int32 npredecessors = 0;
248  // link node as successor of list elements
249  for (kmp_depnode_list_t *p = plist; p; p = p->next) {
250  kmp_depnode_t *dep = p->node;
251  if (dep->dn.task) {
252  KMP_ACQUIRE_DEPNODE(gtid, dep);
253  if (dep->dn.task) {
254  __kmp_track_dependence(gtid, dep, node, task);
255  dep->dn.successors = __kmp_add_node(thread, dep->dn.successors, node);
256  KA_TRACE(40, ("__kmp_process_deps: T#%d adding dependence from %p to "
257  "%p\n",
258  gtid, KMP_TASK_TO_TASKDATA(dep->dn.task),
259  KMP_TASK_TO_TASKDATA(task)));
260  npredecessors++;
261  }
262  KMP_RELEASE_DEPNODE(gtid, dep);
263  }
264  }
265  return npredecessors;
266 }
267 
268 static inline kmp_int32 __kmp_depnode_link_successor(kmp_int32 gtid,
269  kmp_info_t *thread,
270  kmp_task_t *task,
271  kmp_depnode_t *source,
272  kmp_depnode_t *sink) {
273  if (!sink)
274  return 0;
275  kmp_int32 npredecessors = 0;
276  if (sink->dn.task) {
277  // synchronously add source to sink' list of successors
278  KMP_ACQUIRE_DEPNODE(gtid, sink);
279  if (sink->dn.task) {
280  __kmp_track_dependence(gtid, sink, source, task);
281  sink->dn.successors = __kmp_add_node(thread, sink->dn.successors, source);
282  KA_TRACE(40, ("__kmp_process_deps: T#%d adding dependence from %p to "
283  "%p\n",
284  gtid, KMP_TASK_TO_TASKDATA(sink->dn.task),
285  KMP_TASK_TO_TASKDATA(task)));
286  npredecessors++;
287  }
288  KMP_RELEASE_DEPNODE(gtid, sink);
289  }
290  return npredecessors;
291 }
292 
293 template <bool filter>
294 static inline kmp_int32
295 __kmp_process_deps(kmp_int32 gtid, kmp_depnode_t *node, kmp_dephash_t **hash,
296  bool dep_barrier, kmp_int32 ndeps,
297  kmp_depend_info_t *dep_list, kmp_task_t *task) {
298  KA_TRACE(30, ("__kmp_process_deps<%d>: T#%d processing %d dependences : "
299  "dep_barrier = %d\n",
300  filter, gtid, ndeps, dep_barrier));
301 
302  kmp_info_t *thread = __kmp_threads[gtid];
303  kmp_int32 npredecessors = 0;
304  for (kmp_int32 i = 0; i < ndeps; i++) {
305  const kmp_depend_info_t *dep = &dep_list[i];
306 
307  if (filter && dep->base_addr == 0)
308  continue; // skip filtered entries
309 
310  kmp_dephash_entry_t *info =
311  __kmp_dephash_find(thread, hash, dep->base_addr);
312  kmp_depnode_t *last_out = info->last_out;
313  kmp_depnode_list_t *last_set = info->last_set;
314  kmp_depnode_list_t *prev_set = info->prev_set;
315 
316  if (dep->flags.out) { // out or inout --> clean lists if any
317  if (last_set) {
318  npredecessors +=
319  __kmp_depnode_link_successor(gtid, thread, task, node, last_set);
320  __kmp_depnode_list_free(thread, last_set);
321  __kmp_depnode_list_free(thread, prev_set);
322  info->last_set = NULL;
323  info->prev_set = NULL;
324  info->last_flag = 0; // no sets in this dephash entry
325  } else {
326  npredecessors +=
327  __kmp_depnode_link_successor(gtid, thread, task, node, last_out);
328  }
329  __kmp_node_deref(thread, last_out);
330  if (!dep_barrier) {
331  info->last_out = __kmp_node_ref(node);
332  } else {
333  // if this is a sync point in the serial sequence, then the previous
334  // outputs are guaranteed to be completed after the execution of this
335  // task so the previous output nodes can be cleared.
336  info->last_out = NULL;
337  }
338  } else { // either IN or MTX or SET
339  if (info->last_flag == 0 || info->last_flag == dep->flag) {
340  // last_set either didn't exist or of same dep kind
341  // link node as successor of the last_out if any
342  npredecessors +=
343  __kmp_depnode_link_successor(gtid, thread, task, node, last_out);
344  // link node as successor of all nodes in the prev_set if any
345  npredecessors +=
346  __kmp_depnode_link_successor(gtid, thread, task, node, prev_set);
347  } else { // last_set is of different dep kind, make it prev_set
348  // link node as successor of all nodes in the last_set
349  npredecessors +=
350  __kmp_depnode_link_successor(gtid, thread, task, node, last_set);
351  // clean last_out if any
352  __kmp_node_deref(thread, last_out);
353  info->last_out = NULL;
354  // clean prev_set if any
355  __kmp_depnode_list_free(thread, prev_set);
356  // move last_set to prev_set, new last_set will be allocated
357  info->prev_set = last_set;
358  info->last_set = NULL;
359  }
360  info->last_flag = dep->flag; // store dep kind of the last_set
361  info->last_set = __kmp_add_node(thread, info->last_set, node);
362 
363  // check if we are processing MTX dependency
364  if (dep->flag == KMP_DEP_MTX) {
365  if (info->mtx_lock == NULL) {
366  info->mtx_lock = (kmp_lock_t *)__kmp_allocate(sizeof(kmp_lock_t));
367  __kmp_init_lock(info->mtx_lock);
368  }
369  KMP_DEBUG_ASSERT(node->dn.mtx_num_locks < MAX_MTX_DEPS);
370  kmp_int32 m;
371  // Save lock in node's array
372  for (m = 0; m < MAX_MTX_DEPS; ++m) {
373  // sort pointers in decreasing order to avoid potential livelock
374  if (node->dn.mtx_locks[m] < info->mtx_lock) {
375  KMP_DEBUG_ASSERT(!node->dn.mtx_locks[node->dn.mtx_num_locks]);
376  for (int n = node->dn.mtx_num_locks; n > m; --n) {
377  // shift right all lesser non-NULL pointers
378  KMP_DEBUG_ASSERT(node->dn.mtx_locks[n - 1] != NULL);
379  node->dn.mtx_locks[n] = node->dn.mtx_locks[n - 1];
380  }
381  node->dn.mtx_locks[m] = info->mtx_lock;
382  break;
383  }
384  }
385  KMP_DEBUG_ASSERT(m < MAX_MTX_DEPS); // must break from loop
386  node->dn.mtx_num_locks++;
387  }
388  }
389  }
390  KA_TRACE(30, ("__kmp_process_deps<%d>: T#%d found %d predecessors\n", filter,
391  gtid, npredecessors));
392  return npredecessors;
393 }
394 
395 #define NO_DEP_BARRIER (false)
396 #define DEP_BARRIER (true)
397 
398 // returns true if the task has any outstanding dependence
399 static bool __kmp_check_deps(kmp_int32 gtid, kmp_depnode_t *node,
400  kmp_task_t *task, kmp_dephash_t **hash,
401  bool dep_barrier, kmp_int32 ndeps,
402  kmp_depend_info_t *dep_list,
403  kmp_int32 ndeps_noalias,
404  kmp_depend_info_t *noalias_dep_list) {
405  int i, n_mtxs = 0;
406 #if KMP_DEBUG
407  kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
408 #endif
409  KA_TRACE(20, ("__kmp_check_deps: T#%d checking dependences for task %p : %d "
410  "possibly aliased dependences, %d non-aliased dependences : "
411  "dep_barrier=%d .\n",
412  gtid, taskdata, ndeps, ndeps_noalias, dep_barrier));
413 
414  // Filter deps in dep_list
415  // TODO: Different algorithm for large dep_list ( > 10 ? )
416  for (i = 0; i < ndeps; i++) {
417  if (dep_list[i].base_addr != 0) {
418  KMP_DEBUG_ASSERT(
419  dep_list[i].flag == KMP_DEP_IN || dep_list[i].flag == KMP_DEP_OUT ||
420  dep_list[i].flag == KMP_DEP_INOUT ||
421  dep_list[i].flag == KMP_DEP_MTX || dep_list[i].flag == KMP_DEP_SET);
422  for (int j = i + 1; j < ndeps; j++) {
423  if (dep_list[i].base_addr == dep_list[j].base_addr) {
424  if (dep_list[i].flag != dep_list[j].flag) {
425  // two different dependences on same address work identical to OUT
426  dep_list[i].flag = KMP_DEP_OUT;
427  }
428  dep_list[j].base_addr = 0; // Mark j element as void
429  }
430  }
431  if (dep_list[i].flag == KMP_DEP_MTX) {
432  // limit number of mtx deps to MAX_MTX_DEPS per node
433  if (n_mtxs < MAX_MTX_DEPS && task != NULL) {
434  ++n_mtxs;
435  } else {
436  dep_list[i].flag = KMP_DEP_OUT; // downgrade mutexinoutset to inout
437  }
438  }
439  }
440  }
441 
442  // doesn't need to be atomic as no other thread is going to be accessing this
443  // node just yet.
444  // npredecessors is set -1 to ensure that none of the releasing tasks queues
445  // this task before we have finished processing all the dependences
446  node->dn.npredecessors = -1;
447 
448  // used to pack all npredecessors additions into a single atomic operation at
449  // the end
450  int npredecessors;
451 
452  npredecessors = __kmp_process_deps<true>(gtid, node, hash, dep_barrier, ndeps,
453  dep_list, task);
454  npredecessors += __kmp_process_deps<false>(
455  gtid, node, hash, dep_barrier, ndeps_noalias, noalias_dep_list, task);
456 
457  node->dn.task = task;
458  KMP_MB();
459 
460  // Account for our initial fake value
461  npredecessors++;
462 
463  // Update predecessors and obtain current value to check if there are still
464  // any outstanding dependences (some tasks may have finished while we
465  // processed the dependences)
466  npredecessors =
467  node->dn.npredecessors.fetch_add(npredecessors) + npredecessors;
468 
469  KA_TRACE(20, ("__kmp_check_deps: T#%d found %d predecessors for task %p \n",
470  gtid, npredecessors, taskdata));
471 
472  // beyond this point the task could be queued (and executed) by a releasing
473  // task...
474  return npredecessors > 0 ? true : false;
475 }
476 
493 kmp_int32 __kmpc_omp_task_with_deps(ident_t *loc_ref, kmp_int32 gtid,
494  kmp_task_t *new_task, kmp_int32 ndeps,
495  kmp_depend_info_t *dep_list,
496  kmp_int32 ndeps_noalias,
497  kmp_depend_info_t *noalias_dep_list) {
498 
499  kmp_taskdata_t *new_taskdata = KMP_TASK_TO_TASKDATA(new_task);
500  KA_TRACE(10, ("__kmpc_omp_task_with_deps(enter): T#%d loc=%p task=%p\n", gtid,
501  loc_ref, new_taskdata));
502  __kmp_assert_valid_gtid(gtid);
503  kmp_info_t *thread = __kmp_threads[gtid];
504  kmp_taskdata_t *current_task = thread->th.th_current_task;
505 
506 #if OMPT_SUPPORT
507  if (ompt_enabled.enabled) {
508  if (!current_task->ompt_task_info.frame.enter_frame.ptr)
509  current_task->ompt_task_info.frame.enter_frame.ptr =
510  OMPT_GET_FRAME_ADDRESS(0);
511  if (ompt_enabled.ompt_callback_task_create) {
512  ompt_callbacks.ompt_callback(ompt_callback_task_create)(
513  &(current_task->ompt_task_info.task_data),
514  &(current_task->ompt_task_info.frame),
515  &(new_taskdata->ompt_task_info.task_data),
516  ompt_task_explicit | TASK_TYPE_DETAILS_FORMAT(new_taskdata), 1,
517  OMPT_LOAD_OR_GET_RETURN_ADDRESS(gtid));
518  }
519 
520  new_taskdata->ompt_task_info.frame.enter_frame.ptr =
521  OMPT_GET_FRAME_ADDRESS(0);
522  }
523 
524 #if OMPT_OPTIONAL
525  /* OMPT grab all dependences if requested by the tool */
526  if (ndeps + ndeps_noalias > 0 && ompt_enabled.ompt_callback_dependences) {
527  kmp_int32 i;
528 
529  int ompt_ndeps = ndeps + ndeps_noalias;
530  ompt_dependence_t *ompt_deps = (ompt_dependence_t *)KMP_OMPT_DEPS_ALLOC(
531  thread, (ndeps + ndeps_noalias) * sizeof(ompt_dependence_t));
532 
533  KMP_ASSERT(ompt_deps != NULL);
534 
535  for (i = 0; i < ndeps; i++) {
536  ompt_deps[i].variable.ptr = (void *)dep_list[i].base_addr;
537  if (dep_list[i].flags.in && dep_list[i].flags.out)
538  ompt_deps[i].dependence_type = ompt_dependence_type_inout;
539  else if (dep_list[i].flags.out)
540  ompt_deps[i].dependence_type = ompt_dependence_type_out;
541  else if (dep_list[i].flags.in)
542  ompt_deps[i].dependence_type = ompt_dependence_type_in;
543  else if (dep_list[i].flags.mtx)
544  ompt_deps[i].dependence_type = ompt_dependence_type_mutexinoutset;
545  else if (dep_list[i].flags.set)
546  ompt_deps[i].dependence_type = ompt_dependence_type_inoutset;
547  }
548  for (i = 0; i < ndeps_noalias; i++) {
549  ompt_deps[ndeps + i].variable.ptr = (void *)noalias_dep_list[i].base_addr;
550  if (noalias_dep_list[i].flags.in && noalias_dep_list[i].flags.out)
551  ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_inout;
552  else if (noalias_dep_list[i].flags.out)
553  ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_out;
554  else if (noalias_dep_list[i].flags.in)
555  ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_in;
556  else if (noalias_dep_list[i].flags.mtx)
557  ompt_deps[ndeps + i].dependence_type =
558  ompt_dependence_type_mutexinoutset;
559  else if (noalias_dep_list[i].flags.set)
560  ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_inoutset;
561  }
562  ompt_callbacks.ompt_callback(ompt_callback_dependences)(
563  &(new_taskdata->ompt_task_info.task_data), ompt_deps, ompt_ndeps);
564  /* We can now free the allocated memory for the dependences */
565  /* For OMPD we might want to delay the free until end of this function */
566  KMP_OMPT_DEPS_FREE(thread, ompt_deps);
567  }
568 #endif /* OMPT_OPTIONAL */
569 #endif /* OMPT_SUPPORT */
570 
571  bool serial = current_task->td_flags.team_serial ||
572  current_task->td_flags.tasking_ser ||
573  current_task->td_flags.final;
574  kmp_task_team_t *task_team = thread->th.th_task_team;
575  serial = serial &&
576  !(task_team && (task_team->tt.tt_found_proxy_tasks ||
577  task_team->tt.tt_hidden_helper_task_encountered));
578 
579  if (!serial && (ndeps > 0 || ndeps_noalias > 0)) {
580  /* if no dependences have been tracked yet, create the dependence hash */
581  if (current_task->td_dephash == NULL)
582  current_task->td_dephash = __kmp_dephash_create(thread, current_task);
583 
584 #if USE_FAST_MEMORY
585  kmp_depnode_t *node =
586  (kmp_depnode_t *)__kmp_fast_allocate(thread, sizeof(kmp_depnode_t));
587 #else
588  kmp_depnode_t *node =
589  (kmp_depnode_t *)__kmp_thread_malloc(thread, sizeof(kmp_depnode_t));
590 #endif
591 
592  __kmp_init_node(node);
593  new_taskdata->td_depnode = node;
594 
595  if (__kmp_check_deps(gtid, node, new_task, &current_task->td_dephash,
596  NO_DEP_BARRIER, ndeps, dep_list, ndeps_noalias,
597  noalias_dep_list)) {
598  KA_TRACE(10, ("__kmpc_omp_task_with_deps(exit): T#%d task had blocking "
599  "dependences: "
600  "loc=%p task=%p, return: TASK_CURRENT_NOT_QUEUED\n",
601  gtid, loc_ref, new_taskdata));
602 #if OMPT_SUPPORT
603  if (ompt_enabled.enabled) {
604  current_task->ompt_task_info.frame.enter_frame = ompt_data_none;
605  }
606 #endif
607  return TASK_CURRENT_NOT_QUEUED;
608  }
609  } else {
610  KA_TRACE(10, ("__kmpc_omp_task_with_deps(exit): T#%d ignored dependences "
611  "for task (serialized) loc=%p task=%p\n",
612  gtid, loc_ref, new_taskdata));
613  }
614 
615  KA_TRACE(10, ("__kmpc_omp_task_with_deps(exit): T#%d task had no blocking "
616  "dependences : "
617  "loc=%p task=%p, transferring to __kmp_omp_task\n",
618  gtid, loc_ref, new_taskdata));
619 
620  kmp_int32 ret = __kmp_omp_task(gtid, new_task, true);
621 #if OMPT_SUPPORT
622  if (ompt_enabled.enabled) {
623  current_task->ompt_task_info.frame.enter_frame = ompt_data_none;
624  }
625 #endif
626  return ret;
627 }
628 
629 #if OMPT_SUPPORT
630 void __ompt_taskwait_dep_finish(kmp_taskdata_t *current_task,
631  ompt_data_t *taskwait_task_data) {
632  if (ompt_enabled.ompt_callback_task_schedule) {
633  ompt_callbacks.ompt_callback(ompt_callback_task_schedule)(
634  taskwait_task_data, ompt_taskwait_complete, NULL);
635  }
636  current_task->ompt_task_info.frame.enter_frame.ptr = NULL;
637  *taskwait_task_data = ompt_data_none;
638 }
639 #endif /* OMPT_SUPPORT */
640 
652 void __kmpc_omp_wait_deps(ident_t *loc_ref, kmp_int32 gtid, kmp_int32 ndeps,
653  kmp_depend_info_t *dep_list, kmp_int32 ndeps_noalias,
654  kmp_depend_info_t *noalias_dep_list) {
655  KA_TRACE(10, ("__kmpc_omp_wait_deps(enter): T#%d loc=%p\n", gtid, loc_ref));
656 
657  if (ndeps == 0 && ndeps_noalias == 0) {
658  KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d has no dependences to "
659  "wait upon : loc=%p\n",
660  gtid, loc_ref));
661  return;
662  }
663  __kmp_assert_valid_gtid(gtid);
664  kmp_info_t *thread = __kmp_threads[gtid];
665  kmp_taskdata_t *current_task = thread->th.th_current_task;
666 
667 #if OMPT_SUPPORT
668  // this function represents a taskwait construct with depend clause
669  // We signal 4 events:
670  // - creation of the taskwait task
671  // - dependences of the taskwait task
672  // - schedule and finish of the taskwait task
673  ompt_data_t *taskwait_task_data = &thread->th.ompt_thread_info.task_data;
674  KMP_ASSERT(taskwait_task_data->ptr == NULL);
675  if (ompt_enabled.enabled) {
676  if (!current_task->ompt_task_info.frame.enter_frame.ptr)
677  current_task->ompt_task_info.frame.enter_frame.ptr =
678  OMPT_GET_FRAME_ADDRESS(0);
679  if (ompt_enabled.ompt_callback_task_create) {
680  ompt_callbacks.ompt_callback(ompt_callback_task_create)(
681  &(current_task->ompt_task_info.task_data),
682  &(current_task->ompt_task_info.frame), taskwait_task_data,
683  ompt_task_taskwait | ompt_task_undeferred | ompt_task_mergeable, 1,
684  OMPT_LOAD_OR_GET_RETURN_ADDRESS(gtid));
685  }
686  }
687 
688 #if OMPT_OPTIONAL
689  /* OMPT grab all dependences if requested by the tool */
690  if (ndeps + ndeps_noalias > 0 && ompt_enabled.ompt_callback_dependences) {
691  kmp_int32 i;
692 
693  int ompt_ndeps = ndeps + ndeps_noalias;
694  ompt_dependence_t *ompt_deps = (ompt_dependence_t *)KMP_OMPT_DEPS_ALLOC(
695  thread, (ndeps + ndeps_noalias) * sizeof(ompt_dependence_t));
696 
697  KMP_ASSERT(ompt_deps != NULL);
698 
699  for (i = 0; i < ndeps; i++) {
700  ompt_deps[i].variable.ptr = (void *)dep_list[i].base_addr;
701  if (dep_list[i].flags.in && dep_list[i].flags.out)
702  ompt_deps[i].dependence_type = ompt_dependence_type_inout;
703  else if (dep_list[i].flags.out)
704  ompt_deps[i].dependence_type = ompt_dependence_type_out;
705  else if (dep_list[i].flags.in)
706  ompt_deps[i].dependence_type = ompt_dependence_type_in;
707  else if (dep_list[i].flags.mtx)
708  ompt_deps[ndeps + i].dependence_type =
709  ompt_dependence_type_mutexinoutset;
710  else if (dep_list[i].flags.set)
711  ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_inoutset;
712  }
713  for (i = 0; i < ndeps_noalias; i++) {
714  ompt_deps[ndeps + i].variable.ptr = (void *)noalias_dep_list[i].base_addr;
715  if (noalias_dep_list[i].flags.in && noalias_dep_list[i].flags.out)
716  ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_inout;
717  else if (noalias_dep_list[i].flags.out)
718  ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_out;
719  else if (noalias_dep_list[i].flags.in)
720  ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_in;
721  else if (noalias_dep_list[i].flags.mtx)
722  ompt_deps[ndeps + i].dependence_type =
723  ompt_dependence_type_mutexinoutset;
724  else if (noalias_dep_list[i].flags.set)
725  ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_inoutset;
726  }
727  ompt_callbacks.ompt_callback(ompt_callback_dependences)(
728  taskwait_task_data, ompt_deps, ompt_ndeps);
729  /* We can now free the allocated memory for the dependences */
730  /* For OMPD we might want to delay the free until end of this function */
731  KMP_OMPT_DEPS_FREE(thread, ompt_deps);
732  ompt_deps = NULL;
733  }
734 #endif /* OMPT_OPTIONAL */
735 #endif /* OMPT_SUPPORT */
736 
737  // We can return immediately as:
738  // - dependences are not computed in serial teams (except with proxy tasks)
739  // - if the dephash is not yet created it means we have nothing to wait for
740  bool ignore = current_task->td_flags.team_serial ||
741  current_task->td_flags.tasking_ser ||
742  current_task->td_flags.final;
743  ignore = ignore && thread->th.th_task_team != NULL &&
744  thread->th.th_task_team->tt.tt_found_proxy_tasks == FALSE;
745  ignore = ignore || current_task->td_dephash == NULL;
746 
747  if (ignore) {
748  KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d has no blocking "
749  "dependences : loc=%p\n",
750  gtid, loc_ref));
751 #if OMPT_SUPPORT
752  __ompt_taskwait_dep_finish(current_task, taskwait_task_data);
753 #endif /* OMPT_SUPPORT */
754  return;
755  }
756 
757  kmp_depnode_t node = {0};
758  __kmp_init_node(&node);
759  // the stack owns the node
760  __kmp_node_ref(&node);
761 
762  if (!__kmp_check_deps(gtid, &node, NULL, &current_task->td_dephash,
763  DEP_BARRIER, ndeps, dep_list, ndeps_noalias,
764  noalias_dep_list)) {
765  KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d has no blocking "
766  "dependences : loc=%p\n",
767  gtid, loc_ref));
768 #if OMPT_SUPPORT
769  __ompt_taskwait_dep_finish(current_task, taskwait_task_data);
770 #endif /* OMPT_SUPPORT */
771  return;
772  }
773 
774  int thread_finished = FALSE;
775  kmp_flag_32<false, false> flag(
776  (std::atomic<kmp_uint32> *)&node.dn.npredecessors, 0U);
777  while (node.dn.npredecessors > 0) {
778  flag.execute_tasks(thread, gtid, FALSE,
779  &thread_finished USE_ITT_BUILD_ARG(NULL),
780  __kmp_task_stealing_constraint);
781  }
782 
783 #if OMPT_SUPPORT
784  __ompt_taskwait_dep_finish(current_task, taskwait_task_data);
785 #endif /* OMPT_SUPPORT */
786  KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d finished waiting : loc=%p\n",
787  gtid, loc_ref));
788 }
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)
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.h:233