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  h->last_all = current_dephash->last_all;
90 
91  // make sure buckets are properly initialized
92  for (size_t i = 0; i < new_size; i++) {
93  h->buckets[i] = NULL;
94  }
95 
96  // insert existing elements in the new table
97  for (size_t i = 0; i < current_dephash->size; i++) {
98  kmp_dephash_entry_t *next, *entry;
99  for (entry = current_dephash->buckets[i]; entry; entry = next) {
100  next = entry->next_in_bucket;
101  // Compute the new hash using the new size, and insert the entry in
102  // the new bucket.
103  size_t new_bucket = __kmp_dephash_hash(entry->addr, h->size);
104  entry->next_in_bucket = h->buckets[new_bucket];
105  if (entry->next_in_bucket) {
106  h->nconflicts++;
107  }
108  h->buckets[new_bucket] = entry;
109  }
110  }
111 
112  // Free old hash table
113 #if USE_FAST_MEMORY
114  __kmp_fast_free(thread, current_dephash);
115 #else
116  __kmp_thread_free(thread, current_dephash);
117 #endif
118 
119  return h;
120 }
121 
122 static kmp_dephash_t *__kmp_dephash_create(kmp_info_t *thread,
123  kmp_taskdata_t *current_task) {
124  kmp_dephash_t *h;
125 
126  size_t h_size;
127 
128  if (current_task->td_flags.tasktype == TASK_IMPLICIT)
129  h_size = KMP_DEPHASH_MASTER_SIZE;
130  else
131  h_size = KMP_DEPHASH_OTHER_SIZE;
132 
133  size_t size = h_size * sizeof(kmp_dephash_entry_t *) + sizeof(kmp_dephash_t);
134 
135 #if USE_FAST_MEMORY
136  h = (kmp_dephash_t *)__kmp_fast_allocate(thread, size);
137 #else
138  h = (kmp_dephash_t *)__kmp_thread_malloc(thread, size);
139 #endif
140  h->size = h_size;
141 
142  h->generation = 0;
143  h->nelements = 0;
144  h->nconflicts = 0;
145  h->buckets = (kmp_dephash_entry **)(h + 1);
146  h->last_all = NULL;
147 
148  for (size_t i = 0; i < h_size; i++)
149  h->buckets[i] = 0;
150 
151  return h;
152 }
153 
154 static kmp_dephash_entry *__kmp_dephash_find(kmp_info_t *thread,
155  kmp_dephash_t **hash,
156  kmp_intptr_t addr) {
157  kmp_dephash_t *h = *hash;
158  if (h->nelements != 0 && h->nconflicts / h->size >= 1) {
159  *hash = __kmp_dephash_extend(thread, h);
160  h = *hash;
161  }
162  size_t bucket = __kmp_dephash_hash(addr, h->size);
163 
164  kmp_dephash_entry_t *entry;
165  for (entry = h->buckets[bucket]; entry; entry = entry->next_in_bucket)
166  if (entry->addr == addr)
167  break;
168 
169  if (entry == NULL) {
170 // create entry. This is only done by one thread so no locking required
171 #if USE_FAST_MEMORY
172  entry = (kmp_dephash_entry_t *)__kmp_fast_allocate(
173  thread, sizeof(kmp_dephash_entry_t));
174 #else
175  entry = (kmp_dephash_entry_t *)__kmp_thread_malloc(
176  thread, sizeof(kmp_dephash_entry_t));
177 #endif
178  entry->addr = addr;
179  if (!h->last_all) // no predecessor task with omp_all_memory dependence
180  entry->last_out = NULL;
181  else // else link the omp_all_memory depnode to the new entry
182  entry->last_out = __kmp_node_ref(h->last_all);
183  entry->last_set = NULL;
184  entry->prev_set = NULL;
185  entry->last_flag = 0;
186  entry->mtx_lock = NULL;
187  entry->next_in_bucket = h->buckets[bucket];
188  h->buckets[bucket] = entry;
189  h->nelements++;
190  if (entry->next_in_bucket)
191  h->nconflicts++;
192  }
193  return entry;
194 }
195 
196 static kmp_depnode_list_t *__kmp_add_node(kmp_info_t *thread,
197  kmp_depnode_list_t *list,
198  kmp_depnode_t *node) {
199  kmp_depnode_list_t *new_head;
200 
201 #if USE_FAST_MEMORY
202  new_head = (kmp_depnode_list_t *)__kmp_fast_allocate(
203  thread, sizeof(kmp_depnode_list_t));
204 #else
205  new_head = (kmp_depnode_list_t *)__kmp_thread_malloc(
206  thread, sizeof(kmp_depnode_list_t));
207 #endif
208 
209  new_head->node = __kmp_node_ref(node);
210  new_head->next = list;
211 
212  return new_head;
213 }
214 
215 static inline void __kmp_track_dependence(kmp_int32 gtid, kmp_depnode_t *source,
216  kmp_depnode_t *sink,
217  kmp_task_t *sink_task) {
218 #ifdef KMP_SUPPORT_GRAPH_OUTPUT
219  kmp_taskdata_t *task_source = KMP_TASK_TO_TASKDATA(source->dn.task);
220  // do not use sink->dn.task as that is only filled after the dependences
221  // are already processed!
222  kmp_taskdata_t *task_sink = KMP_TASK_TO_TASKDATA(sink_task);
223 
224  __kmp_printf("%d(%s) -> %d(%s)\n", source->dn.id,
225  task_source->td_ident->psource, sink->dn.id,
226  task_sink->td_ident->psource);
227 #endif
228 #if OMPT_SUPPORT && OMPT_OPTIONAL
229  /* OMPT tracks dependences between task (a=source, b=sink) in which
230  task a blocks the execution of b through the ompt_new_dependence_callback
231  */
232  if (ompt_enabled.ompt_callback_task_dependence) {
233  kmp_taskdata_t *task_source = KMP_TASK_TO_TASKDATA(source->dn.task);
234  ompt_data_t *sink_data;
235  if (sink_task)
236  sink_data = &(KMP_TASK_TO_TASKDATA(sink_task)->ompt_task_info.task_data);
237  else
238  sink_data = &__kmp_threads[gtid]->th.ompt_thread_info.task_data;
239 
240  ompt_callbacks.ompt_callback(ompt_callback_task_dependence)(
241  &(task_source->ompt_task_info.task_data), sink_data);
242  }
243 #endif /* OMPT_SUPPORT && OMPT_OPTIONAL */
244 }
245 
246 static inline kmp_int32
247 __kmp_depnode_link_successor(kmp_int32 gtid, kmp_info_t *thread,
248  kmp_task_t *task, kmp_depnode_t *node,
249  kmp_depnode_list_t *plist) {
250  if (!plist)
251  return 0;
252  kmp_int32 npredecessors = 0;
253  // link node as successor of list elements
254  for (kmp_depnode_list_t *p = plist; p; p = p->next) {
255  kmp_depnode_t *dep = p->node;
256  if (dep->dn.task) {
257  KMP_ACQUIRE_DEPNODE(gtid, dep);
258  if (dep->dn.task) {
259  __kmp_track_dependence(gtid, dep, node, task);
260  dep->dn.successors = __kmp_add_node(thread, dep->dn.successors, node);
261  KA_TRACE(40, ("__kmp_process_deps: T#%d adding dependence from %p to "
262  "%p\n",
263  gtid, KMP_TASK_TO_TASKDATA(dep->dn.task),
264  KMP_TASK_TO_TASKDATA(task)));
265  npredecessors++;
266  }
267  KMP_RELEASE_DEPNODE(gtid, dep);
268  }
269  }
270  return npredecessors;
271 }
272 
273 static inline kmp_int32 __kmp_depnode_link_successor(kmp_int32 gtid,
274  kmp_info_t *thread,
275  kmp_task_t *task,
276  kmp_depnode_t *source,
277  kmp_depnode_t *sink) {
278  if (!sink)
279  return 0;
280  kmp_int32 npredecessors = 0;
281  if (sink->dn.task) {
282  // synchronously add source to sink' list of successors
283  KMP_ACQUIRE_DEPNODE(gtid, sink);
284  if (sink->dn.task) {
285  __kmp_track_dependence(gtid, sink, source, task);
286  sink->dn.successors = __kmp_add_node(thread, sink->dn.successors, source);
287  KA_TRACE(40, ("__kmp_process_deps: T#%d adding dependence from %p to "
288  "%p\n",
289  gtid, KMP_TASK_TO_TASKDATA(sink->dn.task),
290  KMP_TASK_TO_TASKDATA(task)));
291  npredecessors++;
292  }
293  KMP_RELEASE_DEPNODE(gtid, sink);
294  }
295  return npredecessors;
296 }
297 
298 static inline kmp_int32
299 __kmp_process_dep_all(kmp_int32 gtid, kmp_depnode_t *node, kmp_dephash_t *h,
300  bool dep_barrier, kmp_task_t *task) {
301  KA_TRACE(30, ("__kmp_process_dep_all: T#%d processing dep_all, "
302  "dep_barrier = %d\n",
303  gtid, dep_barrier));
304  kmp_info_t *thread = __kmp_threads[gtid];
305  kmp_int32 npredecessors = 0;
306 
307  // process previous omp_all_memory node if any
308  npredecessors +=
309  __kmp_depnode_link_successor(gtid, thread, task, node, h->last_all);
310  __kmp_node_deref(thread, h->last_all);
311  if (!dep_barrier) {
312  h->last_all = __kmp_node_ref(node);
313  } else {
314  // if this is a sync point in the serial sequence, then the previous
315  // outputs are guaranteed to be completed after the execution of this
316  // task so the previous output nodes can be cleared.
317  h->last_all = NULL;
318  }
319 
320  // process all regular dependences
321  for (size_t i = 0; i < h->size; i++) {
322  kmp_dephash_entry_t *info = h->buckets[i];
323  if (!info) // skip empty slots in dephash
324  continue;
325  for (; info; info = info->next_in_bucket) {
326  // for each entry the omp_all_memory works as OUT dependence
327  kmp_depnode_t *last_out = info->last_out;
328  kmp_depnode_list_t *last_set = info->last_set;
329  kmp_depnode_list_t *prev_set = info->prev_set;
330  if (last_set) {
331  npredecessors +=
332  __kmp_depnode_link_successor(gtid, thread, task, node, last_set);
333  __kmp_depnode_list_free(thread, last_set);
334  __kmp_depnode_list_free(thread, prev_set);
335  info->last_set = NULL;
336  info->prev_set = NULL;
337  info->last_flag = 0; // no sets in this dephash entry
338  } else {
339  npredecessors +=
340  __kmp_depnode_link_successor(gtid, thread, task, node, last_out);
341  }
342  __kmp_node_deref(thread, last_out);
343  if (!dep_barrier) {
344  info->last_out = __kmp_node_ref(node);
345  } else {
346  info->last_out = NULL;
347  }
348  }
349  }
350  KA_TRACE(30, ("__kmp_process_dep_all: T#%d found %d predecessors\n", gtid,
351  npredecessors));
352  return npredecessors;
353 }
354 
355 template <bool filter>
356 static inline kmp_int32
357 __kmp_process_deps(kmp_int32 gtid, kmp_depnode_t *node, kmp_dephash_t **hash,
358  bool dep_barrier, kmp_int32 ndeps,
359  kmp_depend_info_t *dep_list, kmp_task_t *task) {
360  KA_TRACE(30, ("__kmp_process_deps<%d>: T#%d processing %d dependences : "
361  "dep_barrier = %d\n",
362  filter, gtid, ndeps, dep_barrier));
363 
364  kmp_info_t *thread = __kmp_threads[gtid];
365  kmp_int32 npredecessors = 0;
366  for (kmp_int32 i = 0; i < ndeps; i++) {
367  const kmp_depend_info_t *dep = &dep_list[i];
368 
369  if (filter && dep->base_addr == 0)
370  continue; // skip filtered entries
371 
372  kmp_dephash_entry_t *info =
373  __kmp_dephash_find(thread, hash, dep->base_addr);
374  kmp_depnode_t *last_out = info->last_out;
375  kmp_depnode_list_t *last_set = info->last_set;
376  kmp_depnode_list_t *prev_set = info->prev_set;
377 
378  if (dep->flags.out) { // out or inout --> clean lists if any
379  if (last_set) {
380  npredecessors +=
381  __kmp_depnode_link_successor(gtid, thread, task, node, last_set);
382  __kmp_depnode_list_free(thread, last_set);
383  __kmp_depnode_list_free(thread, prev_set);
384  info->last_set = NULL;
385  info->prev_set = NULL;
386  info->last_flag = 0; // no sets in this dephash entry
387  } else {
388  npredecessors +=
389  __kmp_depnode_link_successor(gtid, thread, task, node, last_out);
390  }
391  __kmp_node_deref(thread, last_out);
392  if (!dep_barrier) {
393  info->last_out = __kmp_node_ref(node);
394  } else {
395  // if this is a sync point in the serial sequence, then the previous
396  // outputs are guaranteed to be completed after the execution of this
397  // task so the previous output nodes can be cleared.
398  info->last_out = NULL;
399  }
400  } else { // either IN or MTX or SET
401  if (info->last_flag == 0 || info->last_flag == dep->flag) {
402  // last_set either didn't exist or of same dep kind
403  // link node as successor of the last_out if any
404  npredecessors +=
405  __kmp_depnode_link_successor(gtid, thread, task, node, last_out);
406  // link node as successor of all nodes in the prev_set if any
407  npredecessors +=
408  __kmp_depnode_link_successor(gtid, thread, task, node, prev_set);
409  if (dep_barrier) {
410  // clean last_out and prev_set if any; don't touch last_set
411  __kmp_node_deref(thread, last_out);
412  info->last_out = NULL;
413  __kmp_depnode_list_free(thread, prev_set);
414  info->prev_set = NULL;
415  }
416  } else { // last_set is of different dep kind, make it prev_set
417  // link node as successor of all nodes in the last_set
418  npredecessors +=
419  __kmp_depnode_link_successor(gtid, thread, task, node, last_set);
420  // clean last_out if any
421  __kmp_node_deref(thread, last_out);
422  info->last_out = NULL;
423  // clean prev_set if any
424  __kmp_depnode_list_free(thread, prev_set);
425  if (!dep_barrier) {
426  // move last_set to prev_set, new last_set will be allocated
427  info->prev_set = last_set;
428  } else {
429  info->prev_set = NULL;
430  info->last_flag = 0;
431  }
432  info->last_set = NULL;
433  }
434  // for dep_barrier last_flag value should remain:
435  // 0 if last_set is empty, unchanged otherwise
436  if (!dep_barrier) {
437  info->last_flag = dep->flag; // store dep kind of the last_set
438  info->last_set = __kmp_add_node(thread, info->last_set, node);
439  }
440  // check if we are processing MTX dependency
441  if (dep->flag == KMP_DEP_MTX) {
442  if (info->mtx_lock == NULL) {
443  info->mtx_lock = (kmp_lock_t *)__kmp_allocate(sizeof(kmp_lock_t));
444  __kmp_init_lock(info->mtx_lock);
445  }
446  KMP_DEBUG_ASSERT(node->dn.mtx_num_locks < MAX_MTX_DEPS);
447  kmp_int32 m;
448  // Save lock in node's array
449  for (m = 0; m < MAX_MTX_DEPS; ++m) {
450  // sort pointers in decreasing order to avoid potential livelock
451  if (node->dn.mtx_locks[m] < info->mtx_lock) {
452  KMP_DEBUG_ASSERT(!node->dn.mtx_locks[node->dn.mtx_num_locks]);
453  for (int n = node->dn.mtx_num_locks; n > m; --n) {
454  // shift right all lesser non-NULL pointers
455  KMP_DEBUG_ASSERT(node->dn.mtx_locks[n - 1] != NULL);
456  node->dn.mtx_locks[n] = node->dn.mtx_locks[n - 1];
457  }
458  node->dn.mtx_locks[m] = info->mtx_lock;
459  break;
460  }
461  }
462  KMP_DEBUG_ASSERT(m < MAX_MTX_DEPS); // must break from loop
463  node->dn.mtx_num_locks++;
464  }
465  }
466  }
467  KA_TRACE(30, ("__kmp_process_deps<%d>: T#%d found %d predecessors\n", filter,
468  gtid, npredecessors));
469  return npredecessors;
470 }
471 
472 #define NO_DEP_BARRIER (false)
473 #define DEP_BARRIER (true)
474 
475 // returns true if the task has any outstanding dependence
476 static bool __kmp_check_deps(kmp_int32 gtid, kmp_depnode_t *node,
477  kmp_task_t *task, kmp_dephash_t **hash,
478  bool dep_barrier, kmp_int32 ndeps,
479  kmp_depend_info_t *dep_list,
480  kmp_int32 ndeps_noalias,
481  kmp_depend_info_t *noalias_dep_list) {
482  int i, n_mtxs = 0, dep_all = 0;
483 #if KMP_DEBUG
484  kmp_taskdata_t *taskdata = KMP_TASK_TO_TASKDATA(task);
485 #endif
486  KA_TRACE(20, ("__kmp_check_deps: T#%d checking dependences for task %p : %d "
487  "possibly aliased dependences, %d non-aliased dependences : "
488  "dep_barrier=%d .\n",
489  gtid, taskdata, ndeps, ndeps_noalias, dep_barrier));
490 
491  // Filter deps in dep_list
492  // TODO: Different algorithm for large dep_list ( > 10 ? )
493  for (i = 0; i < ndeps; i++) {
494  if (dep_list[i].base_addr != 0 &&
495  dep_list[i].base_addr != (kmp_intptr_t)KMP_SIZE_T_MAX) {
496  KMP_DEBUG_ASSERT(
497  dep_list[i].flag == KMP_DEP_IN || dep_list[i].flag == KMP_DEP_OUT ||
498  dep_list[i].flag == KMP_DEP_INOUT ||
499  dep_list[i].flag == KMP_DEP_MTX || dep_list[i].flag == KMP_DEP_SET);
500  for (int j = i + 1; j < ndeps; j++) {
501  if (dep_list[i].base_addr == dep_list[j].base_addr) {
502  if (dep_list[i].flag != dep_list[j].flag) {
503  // two different dependences on same address work identical to OUT
504  dep_list[i].flag = KMP_DEP_OUT;
505  }
506  dep_list[j].base_addr = 0; // Mark j element as void
507  }
508  }
509  if (dep_list[i].flag == KMP_DEP_MTX) {
510  // limit number of mtx deps to MAX_MTX_DEPS per node
511  if (n_mtxs < MAX_MTX_DEPS && task != NULL) {
512  ++n_mtxs;
513  } else {
514  dep_list[i].flag = KMP_DEP_OUT; // downgrade mutexinoutset to inout
515  }
516  }
517  } else if (dep_list[i].flag == KMP_DEP_ALL ||
518  dep_list[i].base_addr == (kmp_intptr_t)KMP_SIZE_T_MAX) {
519  // omp_all_memory dependence can be marked by compiler by either
520  // (addr=0 && flag=0x80) (flag KMP_DEP_ALL), or (addr=-1).
521  // omp_all_memory overrides all other dependences if any
522  dep_all = 1;
523  break;
524  }
525  }
526 
527  // doesn't need to be atomic as no other thread is going to be accessing this
528  // node just yet.
529  // npredecessors is set -1 to ensure that none of the releasing tasks queues
530  // this task before we have finished processing all the dependences
531  node->dn.npredecessors = -1;
532 
533  // used to pack all npredecessors additions into a single atomic operation at
534  // the end
535  int npredecessors;
536 
537  if (!dep_all) { // regular dependences
538  npredecessors = __kmp_process_deps<true>(gtid, node, hash, dep_barrier,
539  ndeps, dep_list, task);
540  npredecessors += __kmp_process_deps<false>(
541  gtid, node, hash, dep_barrier, ndeps_noalias, noalias_dep_list, task);
542  } else { // omp_all_memory dependence
543  npredecessors = __kmp_process_dep_all(gtid, node, *hash, dep_barrier, task);
544  }
545 
546  node->dn.task = task;
547  KMP_MB();
548 
549  // Account for our initial fake value
550  npredecessors++;
551 
552  // Update predecessors and obtain current value to check if there are still
553  // any outstanding dependences (some tasks may have finished while we
554  // processed the dependences)
555  npredecessors =
556  node->dn.npredecessors.fetch_add(npredecessors) + npredecessors;
557 
558  KA_TRACE(20, ("__kmp_check_deps: T#%d found %d predecessors for task %p \n",
559  gtid, npredecessors, taskdata));
560 
561  // beyond this point the task could be queued (and executed) by a releasing
562  // task...
563  return npredecessors > 0 ? true : false;
564 }
565 
582 kmp_int32 __kmpc_omp_task_with_deps(ident_t *loc_ref, kmp_int32 gtid,
583  kmp_task_t *new_task, kmp_int32 ndeps,
584  kmp_depend_info_t *dep_list,
585  kmp_int32 ndeps_noalias,
586  kmp_depend_info_t *noalias_dep_list) {
587 
588  kmp_taskdata_t *new_taskdata = KMP_TASK_TO_TASKDATA(new_task);
589  KA_TRACE(10, ("__kmpc_omp_task_with_deps(enter): T#%d loc=%p task=%p\n", gtid,
590  loc_ref, new_taskdata));
591  __kmp_assert_valid_gtid(gtid);
592  kmp_info_t *thread = __kmp_threads[gtid];
593  kmp_taskdata_t *current_task = thread->th.th_current_task;
594 
595 #if OMPT_SUPPORT
596  if (ompt_enabled.enabled) {
597  if (!current_task->ompt_task_info.frame.enter_frame.ptr)
598  current_task->ompt_task_info.frame.enter_frame.ptr =
599  OMPT_GET_FRAME_ADDRESS(0);
600  if (ompt_enabled.ompt_callback_task_create) {
601  ompt_callbacks.ompt_callback(ompt_callback_task_create)(
602  &(current_task->ompt_task_info.task_data),
603  &(current_task->ompt_task_info.frame),
604  &(new_taskdata->ompt_task_info.task_data),
605  ompt_task_explicit | TASK_TYPE_DETAILS_FORMAT(new_taskdata), 1,
606  OMPT_LOAD_OR_GET_RETURN_ADDRESS(gtid));
607  }
608 
609  new_taskdata->ompt_task_info.frame.enter_frame.ptr =
610  OMPT_GET_FRAME_ADDRESS(0);
611  }
612 
613 #if OMPT_OPTIONAL
614  /* OMPT grab all dependences if requested by the tool */
615  if (ndeps + ndeps_noalias > 0 && ompt_enabled.ompt_callback_dependences) {
616  kmp_int32 i;
617 
618  int ompt_ndeps = ndeps + ndeps_noalias;
619  ompt_dependence_t *ompt_deps = (ompt_dependence_t *)KMP_OMPT_DEPS_ALLOC(
620  thread, (ndeps + ndeps_noalias) * sizeof(ompt_dependence_t));
621 
622  KMP_ASSERT(ompt_deps != NULL);
623 
624  for (i = 0; i < ndeps; i++) {
625  ompt_deps[i].variable.ptr = (void *)dep_list[i].base_addr;
626  if (dep_list[i].flags.in && dep_list[i].flags.out)
627  ompt_deps[i].dependence_type = ompt_dependence_type_inout;
628  else if (dep_list[i].flags.out)
629  ompt_deps[i].dependence_type = ompt_dependence_type_out;
630  else if (dep_list[i].flags.in)
631  ompt_deps[i].dependence_type = ompt_dependence_type_in;
632  else if (dep_list[i].flags.mtx)
633  ompt_deps[i].dependence_type = ompt_dependence_type_mutexinoutset;
634  else if (dep_list[i].flags.set)
635  ompt_deps[i].dependence_type = ompt_dependence_type_inoutset;
636  }
637  for (i = 0; i < ndeps_noalias; i++) {
638  ompt_deps[ndeps + i].variable.ptr = (void *)noalias_dep_list[i].base_addr;
639  if (noalias_dep_list[i].flags.in && noalias_dep_list[i].flags.out)
640  ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_inout;
641  else if (noalias_dep_list[i].flags.out)
642  ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_out;
643  else if (noalias_dep_list[i].flags.in)
644  ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_in;
645  else if (noalias_dep_list[i].flags.mtx)
646  ompt_deps[ndeps + i].dependence_type =
647  ompt_dependence_type_mutexinoutset;
648  else if (noalias_dep_list[i].flags.set)
649  ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_inoutset;
650  }
651  ompt_callbacks.ompt_callback(ompt_callback_dependences)(
652  &(new_taskdata->ompt_task_info.task_data), ompt_deps, ompt_ndeps);
653  /* We can now free the allocated memory for the dependences */
654  /* For OMPD we might want to delay the free until end of this function */
655  KMP_OMPT_DEPS_FREE(thread, ompt_deps);
656  }
657 #endif /* OMPT_OPTIONAL */
658 #endif /* OMPT_SUPPORT */
659 
660  bool serial = current_task->td_flags.team_serial ||
661  current_task->td_flags.tasking_ser ||
662  current_task->td_flags.final;
663  kmp_task_team_t *task_team = thread->th.th_task_team;
664  serial = serial &&
665  !(task_team && (task_team->tt.tt_found_proxy_tasks ||
666  task_team->tt.tt_hidden_helper_task_encountered));
667 
668  if (!serial && (ndeps > 0 || ndeps_noalias > 0)) {
669  /* if no dependences have been tracked yet, create the dependence hash */
670  if (current_task->td_dephash == NULL)
671  current_task->td_dephash = __kmp_dephash_create(thread, current_task);
672 
673 #if USE_FAST_MEMORY
674  kmp_depnode_t *node =
675  (kmp_depnode_t *)__kmp_fast_allocate(thread, sizeof(kmp_depnode_t));
676 #else
677  kmp_depnode_t *node =
678  (kmp_depnode_t *)__kmp_thread_malloc(thread, sizeof(kmp_depnode_t));
679 #endif
680 
681  __kmp_init_node(node);
682  new_taskdata->td_depnode = node;
683 
684  if (__kmp_check_deps(gtid, node, new_task, &current_task->td_dephash,
685  NO_DEP_BARRIER, ndeps, dep_list, ndeps_noalias,
686  noalias_dep_list)) {
687  KA_TRACE(10, ("__kmpc_omp_task_with_deps(exit): T#%d task had blocking "
688  "dependences: "
689  "loc=%p task=%p, return: TASK_CURRENT_NOT_QUEUED\n",
690  gtid, loc_ref, new_taskdata));
691 #if OMPT_SUPPORT
692  if (ompt_enabled.enabled) {
693  current_task->ompt_task_info.frame.enter_frame = ompt_data_none;
694  }
695 #endif
696  return TASK_CURRENT_NOT_QUEUED;
697  }
698  } else {
699  KA_TRACE(10, ("__kmpc_omp_task_with_deps(exit): T#%d ignored dependences "
700  "for task (serialized) loc=%p task=%p\n",
701  gtid, loc_ref, new_taskdata));
702  }
703 
704  KA_TRACE(10, ("__kmpc_omp_task_with_deps(exit): T#%d task had no blocking "
705  "dependences : "
706  "loc=%p task=%p, transferring to __kmp_omp_task\n",
707  gtid, loc_ref, new_taskdata));
708 
709  kmp_int32 ret = __kmp_omp_task(gtid, new_task, true);
710 #if OMPT_SUPPORT
711  if (ompt_enabled.enabled) {
712  current_task->ompt_task_info.frame.enter_frame = ompt_data_none;
713  }
714 #endif
715  return ret;
716 }
717 
718 #if OMPT_SUPPORT
719 void __ompt_taskwait_dep_finish(kmp_taskdata_t *current_task,
720  ompt_data_t *taskwait_task_data) {
721  if (ompt_enabled.ompt_callback_task_schedule) {
722  ompt_callbacks.ompt_callback(ompt_callback_task_schedule)(
723  taskwait_task_data, ompt_taskwait_complete, NULL);
724  }
725  current_task->ompt_task_info.frame.enter_frame.ptr = NULL;
726  *taskwait_task_data = ompt_data_none;
727 }
728 #endif /* OMPT_SUPPORT */
729 
741 void __kmpc_omp_wait_deps(ident_t *loc_ref, kmp_int32 gtid, kmp_int32 ndeps,
742  kmp_depend_info_t *dep_list, kmp_int32 ndeps_noalias,
743  kmp_depend_info_t *noalias_dep_list) {
744  KA_TRACE(10, ("__kmpc_omp_wait_deps(enter): T#%d loc=%p\n", gtid, loc_ref));
745 
746  if (ndeps == 0 && ndeps_noalias == 0) {
747  KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d has no dependences to "
748  "wait upon : loc=%p\n",
749  gtid, loc_ref));
750  return;
751  }
752  __kmp_assert_valid_gtid(gtid);
753  kmp_info_t *thread = __kmp_threads[gtid];
754  kmp_taskdata_t *current_task = thread->th.th_current_task;
755 
756 #if OMPT_SUPPORT
757  // this function represents a taskwait construct with depend clause
758  // We signal 4 events:
759  // - creation of the taskwait task
760  // - dependences of the taskwait task
761  // - schedule and finish of the taskwait task
762  ompt_data_t *taskwait_task_data = &thread->th.ompt_thread_info.task_data;
763  KMP_ASSERT(taskwait_task_data->ptr == NULL);
764  if (ompt_enabled.enabled) {
765  if (!current_task->ompt_task_info.frame.enter_frame.ptr)
766  current_task->ompt_task_info.frame.enter_frame.ptr =
767  OMPT_GET_FRAME_ADDRESS(0);
768  if (ompt_enabled.ompt_callback_task_create) {
769  ompt_callbacks.ompt_callback(ompt_callback_task_create)(
770  &(current_task->ompt_task_info.task_data),
771  &(current_task->ompt_task_info.frame), taskwait_task_data,
772  ompt_task_taskwait | ompt_task_undeferred | ompt_task_mergeable, 1,
773  OMPT_LOAD_OR_GET_RETURN_ADDRESS(gtid));
774  }
775  }
776 
777 #if OMPT_OPTIONAL
778  /* OMPT grab all dependences if requested by the tool */
779  if (ndeps + ndeps_noalias > 0 && ompt_enabled.ompt_callback_dependences) {
780  kmp_int32 i;
781 
782  int ompt_ndeps = ndeps + ndeps_noalias;
783  ompt_dependence_t *ompt_deps = (ompt_dependence_t *)KMP_OMPT_DEPS_ALLOC(
784  thread, (ndeps + ndeps_noalias) * sizeof(ompt_dependence_t));
785 
786  KMP_ASSERT(ompt_deps != NULL);
787 
788  for (i = 0; i < ndeps; i++) {
789  ompt_deps[i].variable.ptr = (void *)dep_list[i].base_addr;
790  if (dep_list[i].flags.in && dep_list[i].flags.out)
791  ompt_deps[i].dependence_type = ompt_dependence_type_inout;
792  else if (dep_list[i].flags.out)
793  ompt_deps[i].dependence_type = ompt_dependence_type_out;
794  else if (dep_list[i].flags.in)
795  ompt_deps[i].dependence_type = ompt_dependence_type_in;
796  else if (dep_list[i].flags.mtx)
797  ompt_deps[ndeps + i].dependence_type =
798  ompt_dependence_type_mutexinoutset;
799  else if (dep_list[i].flags.set)
800  ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_inoutset;
801  }
802  for (i = 0; i < ndeps_noalias; i++) {
803  ompt_deps[ndeps + i].variable.ptr = (void *)noalias_dep_list[i].base_addr;
804  if (noalias_dep_list[i].flags.in && noalias_dep_list[i].flags.out)
805  ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_inout;
806  else if (noalias_dep_list[i].flags.out)
807  ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_out;
808  else if (noalias_dep_list[i].flags.in)
809  ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_in;
810  else if (noalias_dep_list[i].flags.mtx)
811  ompt_deps[ndeps + i].dependence_type =
812  ompt_dependence_type_mutexinoutset;
813  else if (noalias_dep_list[i].flags.set)
814  ompt_deps[ndeps + i].dependence_type = ompt_dependence_type_inoutset;
815  }
816  ompt_callbacks.ompt_callback(ompt_callback_dependences)(
817  taskwait_task_data, ompt_deps, ompt_ndeps);
818  /* We can now free the allocated memory for the dependences */
819  /* For OMPD we might want to delay the free until end of this function */
820  KMP_OMPT_DEPS_FREE(thread, ompt_deps);
821  ompt_deps = NULL;
822  }
823 #endif /* OMPT_OPTIONAL */
824 #endif /* OMPT_SUPPORT */
825 
826  // We can return immediately as:
827  // - dependences are not computed in serial teams (except with proxy tasks)
828  // - if the dephash is not yet created it means we have nothing to wait for
829  bool ignore = current_task->td_flags.team_serial ||
830  current_task->td_flags.tasking_ser ||
831  current_task->td_flags.final;
832  ignore =
833  ignore && thread->th.th_task_team != NULL &&
834  thread->th.th_task_team->tt.tt_found_proxy_tasks == FALSE &&
835  thread->th.th_task_team->tt.tt_hidden_helper_task_encountered == FALSE;
836  ignore = ignore || current_task->td_dephash == NULL;
837 
838  if (ignore) {
839  KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d has no blocking "
840  "dependences : loc=%p\n",
841  gtid, loc_ref));
842 #if OMPT_SUPPORT
843  __ompt_taskwait_dep_finish(current_task, taskwait_task_data);
844 #endif /* OMPT_SUPPORT */
845  return;
846  }
847 
848  kmp_depnode_t node = {0};
849  __kmp_init_node(&node);
850 
851  if (!__kmp_check_deps(gtid, &node, NULL, &current_task->td_dephash,
852  DEP_BARRIER, ndeps, dep_list, ndeps_noalias,
853  noalias_dep_list)) {
854  KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d has no blocking "
855  "dependences : loc=%p\n",
856  gtid, loc_ref));
857 #if OMPT_SUPPORT
858  __ompt_taskwait_dep_finish(current_task, taskwait_task_data);
859 #endif /* OMPT_SUPPORT */
860  return;
861  }
862 
863  int thread_finished = FALSE;
864  kmp_flag_32<false, false> flag(
865  (std::atomic<kmp_uint32> *)&node.dn.npredecessors, 0U);
866  while (node.dn.npredecessors > 0) {
867  flag.execute_tasks(thread, gtid, FALSE,
868  &thread_finished USE_ITT_BUILD_ARG(NULL),
869  __kmp_task_stealing_constraint);
870  }
871 
872 #if OMPT_SUPPORT
873  __ompt_taskwait_dep_finish(current_task, taskwait_task_data);
874 #endif /* OMPT_SUPPORT */
875  KA_TRACE(10, ("__kmpc_omp_wait_deps(exit): T#%d finished waiting : loc=%p\n",
876  gtid, loc_ref));
877 }
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:234