libgomp/team.c

   1 /* Copyright (C) 2005-2021 Free Software Foundation, Inc.
   2    Contributed by Richard Henderson <rth@redhat.com>.
   3
   4    This file is part of the GNU Offloading and Multi Processing Library
   5    (libgomp).
   6
   7    Libgomp is free software; you can redistribute it and/or modify it
   8    under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3, or (at your option)
  10    any later version.
  11
  12    Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
  13    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  14    FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15    more details.
  16
  17    Under Section 7 of GPL version 3, you are granted additional
  18    permissions described in the GCC Runtime Library Exception, version
  19    3.1, as published by the Free Software Foundation.
  20
  21    You should have received a copy of the GNU General Public License and
  22    a copy of the GCC Runtime Library Exception along with this program;
  23    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24    <http://www.gnu.org/licenses/>.  */
  25
  26 /* This file handles the maintenance of threads in response to team
  27    creation and termination.  */
  28
  29 #include "libgomp.h"
  30 #include "pool.h"
  31 #include <stdlib.h>
  32 #include <string.h>
  33
  34 #ifdef LIBGOMP_USE_PTHREADS
  35 pthread_attr_t gomp_thread_attr;
  36
  37 /* This key is for the thread destructor.  */
  38 pthread_key_t gomp_thread_destructor;
  39
  40
  41 /* This is the libgomp per-thread data structure.  */
  42 #if defined HAVE_TLS || defined USE_EMUTLS
  43 __thread struct gomp_thread gomp_tls_data;
  44 #else
  45 pthread_key_t gomp_tls_key;
  46 #endif
  47
  48
  49 /* This structure is used to communicate across pthread_create.  */
  50
  51 struct gomp_thread_start_data
  52 {
  53   void (*fn) (void *);
  54   void *fn_data;
  55   struct gomp_team_state ts;
  56   struct gomp_task *task;
  57   struct gomp_thread_pool *thread_pool;
  58   unsigned int place;
  59   unsigned int num_teams;
  60   unsigned int team_num;
  61   bool nested;
  62   pthread_t handle;
  63 };
  64
  65
  66 /* This function is a pthread_create entry point.  This contains the idle
  67    loop in which a thread waits to be called up to become part of a team.  */
  68
  69 static void *
  70 gomp_thread_start (void *xdata)
  71 {
  72   struct gomp_thread_start_data *data = xdata;
  73   struct gomp_thread *thr;
  74   struct gomp_thread_pool *pool;
  75   void (*local_fn) (void *);
  76   void *local_data;
  77
  78 #if defined HAVE_TLS || defined USE_EMUTLS
  79   thr = &gomp_tls_data;
  80 #else
  81   struct gomp_thread local_thr;
  82   thr = &local_thr;
  83 #endif
  84   gomp_sem_init (&thr->release, 0);
  85
  86   /* Extract what we need from data.  */
  87   local_fn = data->fn;
  88   local_data = data->fn_data;
  89   thr->thread_pool = data->thread_pool;
  90   thr->ts = data->ts;
  91   thr->task = data->task;
  92   thr->place = data->place;
  93   thr->num_teams = data->num_teams;
  94   thr->team_num = data->team_num;
  95 #ifdef GOMP_NEEDS_THREAD_HANDLE
  96   thr->handle = data->handle;
  97 #endif
  98 #if !(defined HAVE_TLS || defined USE_EMUTLS)
  99   pthread_setspecific (gomp_tls_key, thr);
 100 #endif
 101
 102   thr->ts.team->ordered_release[thr->ts.team_id] = &thr->release;
 103
 104   /* Make thread pool local. */
 105   pool = thr->thread_pool;
 106
 107   if (data->nested)
 108     {
 109       struct gomp_team *team = thr->ts.team;
 110       struct gomp_task *task = thr->task;
 111
 112       gomp_barrier_wait (&team->barrier);
 113
 114       local_fn (local_data);
 115       gomp_team_barrier_wait_final (&team->barrier);
 116       gomp_finish_task (task);
 117       gomp_barrier_wait_last (&team->barrier);
 118     }
 119   else
 120     {
 121       pool->threads[thr->ts.team_id] = thr;
 122
 123       gomp_simple_barrier_wait (&pool->threads_dock);
 124       do
 125         {
 126           struct gomp_team *team = thr->ts.team;
 127           struct gomp_task *task = thr->task;
 128
 129           local_fn (local_data);
 130           gomp_team_barrier_wait_final (&team->barrier);
 131           gomp_finish_task (task);
 132
 133           gomp_simple_barrier_wait (&pool->threads_dock);
 134
 135           local_fn = thr->fn;
 136           local_data = thr->data;
 137           thr->fn = NULL;
 138         }
 139       while (local_fn);
 140     }
 141
 142   gomp_sem_destroy (&thr->release);
 143   pthread_detach (pthread_self ());
 144   thr->thread_pool = NULL;
 145   thr->task = NULL;
 146   return NULL;
 147 }
 148 #endif
 149
 150 static inline struct gomp_team *
 151 get_last_team (unsigned nthreads)
 152 {
 153   struct gomp_thread *thr = gomp_thread ();
 154   if (thr->ts.team == NULL)
 155     {
 156       struct gomp_thread_pool *pool = gomp_get_thread_pool (thr, nthreads);
 157       struct gomp_team *last_team = pool->last_team;
 158       if (last_team != NULL && last_team->nthreads == nthreads)
 159         {
 160           pool->last_team = NULL;
 161           return last_team;
 162         }
 163     }
 164   return NULL;
 165 }
 166
 167 /* Create a new team data structure.  */
 168
 169 struct gomp_team *
 170 gomp_new_team (unsigned nthreads)
 171 {
 172   struct gomp_team *team;
 173   int i;
 174
 175   team = get_last_team (nthreads);
 176   if (team == NULL)
 177     {
 178       size_t extra = sizeof (team->ordered_release[0])
 179                      + sizeof (team->implicit_task[0]);
 180 #ifdef GOMP_USE_ALIGNED_WORK_SHARES
 181       team = gomp_aligned_alloc (__alignof (struct gomp_team),
 182                                  sizeof (*team) + nthreads * extra);
 183 #else
 184       team = team_malloc (sizeof (*team) + nthreads * extra);
 185 #endif
 186
 187 #ifndef HAVE_SYNC_BUILTINS
 188       gomp_mutex_init (&team->work_share_list_free_lock);
 189 #endif
 190       gomp_barrier_init (&team->barrier, nthreads);
 191       gomp_mutex_init (&team->task_lock);
 192
 193       team->nthreads = nthreads;
 194     }
 195
 196   team->work_share_chunk = 8;
 197 #ifdef HAVE_SYNC_BUILTINS
 198   team->single_count = 0;
 199 #endif
 200   team->work_shares_to_free = &team->work_shares[0];
 201   gomp_init_work_share (&team->work_shares[0], 0, nthreads);
 202   team->work_shares[0].next_alloc = NULL;
 203   team->work_share_list_free = NULL;
 204   team->work_share_list_alloc = &team->work_shares[1];
 205   for (i = 1; i < 7; i++)
 206     team->work_shares[i].next_free = &team->work_shares[i + 1];
 207   team->work_shares[i].next_free = NULL;
 208
 209   gomp_sem_init (&team->master_release, 0);
 210   team->ordered_release = (void *) &team->implicit_task[nthreads];
 211   team->ordered_release[0] = &team->master_release;
 212
 213   priority_queue_init (&team->task_queue);
 214   team->task_count = 0;
 215   team->task_queued_count = 0;
 216   team->task_running_count = 0;
 217   team->work_share_cancelled = 0;
 218   team->team_cancelled = 0;
 219
 220   team->task_detach_count = 0;
 221
 222   return team;
 223 }
 224
 225
 226 /* Free a team data structure.  */
 227
 228 static void
 229 free_team (struct gomp_team *team)
 230 {
 231 #ifndef HAVE_SYNC_BUILTINS
 232   gomp_mutex_destroy (&team->work_share_list_free_lock);
 233 #endif
 234   gomp_barrier_destroy (&team->barrier);
 235   gomp_mutex_destroy (&team->task_lock);
 236   priority_queue_free (&team->task_queue);
 237   team_free (team);
 238 }
 239
 240 static void
 241 gomp_free_pool_helper (void *thread_pool)
 242 {
 243   struct gomp_thread *thr = gomp_thread ();
 244   struct gomp_thread_pool *pool
 245     = (struct gomp_thread_pool *) thread_pool;
 246   gomp_simple_barrier_wait_last (&pool->threads_dock);
 247   gomp_sem_destroy (&thr->release);
 248   thr->thread_pool = NULL;
 249   thr->task = NULL;
 250 #ifdef LIBGOMP_USE_PTHREADS
 251   pthread_detach (pthread_self ());
 252   pthread_exit (NULL);
 253 #elif defined(__nvptx__)
 254   asm ("exit;");
 255 #elif defined(__AMDGCN__)
 256   asm ("s_dcache_wb\n\t"
 257        "s_endpgm");
 258 #else
 259 #error gomp_free_pool_helper must terminate the thread
 260 #endif
 261 }
 262
 263 /* Free a thread pool and release its threads. */
 264
 265 void
 266 gomp_free_thread (void *arg __attribute__((unused)))
 267 {
 268   struct gomp_thread *thr = gomp_thread ();
 269   struct gomp_thread_pool *pool = thr->thread_pool;
 270   if (pool)
 271     {
 272       if (pool->threads_used > 0)
 273         {
 274           int i;
 275           for (i = 1; i < pool->threads_used; i++)
 276             {
 277               struct gomp_thread *nthr = pool->threads[i];
 278               nthr->fn = gomp_free_pool_helper;
 279               nthr->data = pool;
 280             }
 281           /* This barrier undocks threads docked on pool->threads_dock.  */
 282           gomp_simple_barrier_wait (&pool->threads_dock);
 283           /* And this waits till all threads have called gomp_barrier_wait_last
 284              in gomp_free_pool_helper.  */
 285           gomp_simple_barrier_wait (&pool->threads_dock);
 286           /* Now it is safe to destroy the barrier and free the pool.  */
 287           gomp_simple_barrier_destroy (&pool->threads_dock);
 288
 289 #ifdef HAVE_SYNC_BUILTINS
 290           __sync_fetch_and_add (&gomp_managed_threads,
 291                                 1L - pool->threads_used);
 292 #else
 293           gomp_mutex_lock (&gomp_managed_threads_lock);
 294           gomp_managed_threads -= pool->threads_used - 1L;
 295           gomp_mutex_unlock (&gomp_managed_threads_lock);
 296 #endif
 297         }
 298       if (pool->last_team)
 299         free_team (pool->last_team);
 300 #ifndef __nvptx__
 301       team_free (pool->threads);
 302       team_free (pool);
 303 #endif
 304       thr->thread_pool = NULL;
 305     }
 306   if (thr->ts.level == 0 && __builtin_expect (thr->ts.team != NULL, 0))
 307     gomp_team_end ();
 308   if (thr->task != NULL)
 309     {
 310       struct gomp_task *task = thr->task;
 311       gomp_end_task ();
 312       free (task);
 313     }
 314 }
 315
 316 /* Launch a team.  */
 317
 318 #ifdef LIBGOMP_USE_PTHREADS
 319 void
 320 gomp_team_start (void (*fn) (void *), void *data, unsigned nthreads,
 321                  unsigned flags, struct gomp_team *team,
 322                  struct gomp_taskgroup *taskgroup)
 323 {
 324   struct gomp_thread_start_data *start_data = NULL;
 325   struct gomp_thread *thr, *nthr;
 326   struct gomp_task *task;
 327   struct gomp_task_icv *icv;
 328   bool nested;
 329   struct gomp_thread_pool *pool;
 330   unsigned i, n, old_threads_used = 0;
 331   pthread_attr_t thread_attr, *attr;
 332   unsigned long nthreads_var;
 333   char bind, bind_var;
 334   unsigned int s = 0, rest = 0, p = 0, k = 0;
 335   unsigned int affinity_count = 0;
 336   struct gomp_thread **affinity_thr = NULL;
 337   bool force_display = false;
 338
 339   thr = gomp_thread ();
 340   nested = thr->ts.level;
 341   pool = thr->thread_pool;
 342   task = thr->task;
 343   icv = task ? &task->icv : &gomp_global_icv;
 344   if (__builtin_expect (gomp_places_list != NULL, 0) && thr->place == 0)
 345     {
 346       gomp_init_affinity ();
 347       if (__builtin_expect (gomp_display_affinity_var, 0) && nthreads == 1)
 348         gomp_display_affinity_thread (gomp_thread_self (), &thr->ts,
 349                                       thr->place);
 350     }
 351
 352   /* Always save the previous state, even if this isn't a nested team.
 353      In particular, we should save any work share state from an outer
 354      orphaned work share construct.  */
 355   team->prev_ts = thr->ts;
 356
 357   thr->ts.team = team;
 358   thr->ts.team_id = 0;
 359   ++thr->ts.level;
 360   if (nthreads > 1)
 361     ++thr->ts.active_level;
 362   thr->ts.work_share = &team->work_shares[0];
 363   thr->ts.last_work_share = NULL;
 364 #ifdef HAVE_SYNC_BUILTINS
 365   thr->ts.single_count = 0;
 366 #endif
 367   thr->ts.static_trip = 0;
 368   thr->task = &team->implicit_task[0];
 369 #ifdef GOMP_NEEDS_THREAD_HANDLE
 370   thr->handle = pthread_self ();
 371 #endif
 372   nthreads_var = icv->nthreads_var;
 373   if (__builtin_expect (gomp_nthreads_var_list != NULL, 0)
 374       && thr->ts.level < gomp_nthreads_var_list_len)
 375     nthreads_var = gomp_nthreads_var_list[thr->ts.level];
 376   bind_var = icv->bind_var;
 377   if (bind_var != omp_proc_bind_false && (flags & 7) != omp_proc_bind_false)
 378     bind_var = flags & 7;
 379   bind = bind_var;
 380   if (__builtin_expect (gomp_bind_var_list != NULL, 0)
 381       && thr->ts.level < gomp_bind_var_list_len)
 382     bind_var = gomp_bind_var_list[thr->ts.level];
 383   gomp_init_task (thr->task, task, icv);
 384   thr->task->taskgroup = taskgroup;
 385   team->implicit_task[0].icv.nthreads_var = nthreads_var;
 386   team->implicit_task[0].icv.bind_var = bind_var;
 387
 388   if (nthreads == 1)
 389     return;
 390
 391   i = 1;
 392
 393   if (__builtin_expect (gomp_places_list != NULL, 0))
 394     {
 395       /* Depending on chosen proc_bind model, set subpartition
 396          for the master thread and initialize helper variables
 397          P and optionally S, K and/or REST used by later place
 398          computation for each additional thread.  */
 399       p = thr->place - 1;
 400       switch (bind)
 401         {
 402         case omp_proc_bind_true:
 403         case omp_proc_bind_close:
 404           if (nthreads > thr->ts.place_partition_len)
 405             {
 406               /* T > P.  S threads will be placed in each place,
 407                  and the final REM threads placed one by one
 408                  into the already occupied places.  */
 409               s = nthreads / thr->ts.place_partition_len;
 410               rest = nthreads % thr->ts.place_partition_len;
 411             }
 412           else
 413             s = 1;
 414           k = 1;
 415           break;
 416         case omp_proc_bind_master:
 417           /* Each thread will be bound to master's place.  */
 418           break;
 419         case omp_proc_bind_spread:
 420           if (nthreads <= thr->ts.place_partition_len)
 421             {
 422               /* T <= P.  Each subpartition will have in between s
 423                  and s+1 places (subpartitions starting at or
 424                  after rest will have s places, earlier s+1 places),
 425                  each thread will be bound to the first place in
 426                  its subpartition (except for the master thread
 427                  that can be bound to another place in its
 428                  subpartition).  */
 429               s = thr->ts.place_partition_len / nthreads;
 430               rest = thr->ts.place_partition_len % nthreads;
 431               rest = (s + 1) * rest + thr->ts.place_partition_off;
 432               if (p < rest)
 433                 {
 434                   p -= (p - thr->ts.place_partition_off) % (s + 1);
 435                   thr->ts.place_partition_len = s + 1;
 436                 }
 437               else
 438                 {
 439                   p -= (p - rest) % s;
 440                   thr->ts.place_partition_len = s;
 441                 }
 442               thr->ts.place_partition_off = p;
 443             }
 444           else
 445             {
 446               /* T > P.  Each subpartition will have just a single
 447                  place and we'll place between s and s+1
 448                  threads into each subpartition.  */
 449               s = nthreads / thr->ts.place_partition_len;
 450               rest = nthreads % thr->ts.place_partition_len;
 451               thr->ts.place_partition_off = p;
 452               thr->ts.place_partition_len = 1;
 453               k = 1;
 454             }
 455           break;
 456         }
 457     }
 458   else
 459     bind = omp_proc_bind_false;
 460
 461   /* We only allow the reuse of idle threads for non-nested PARALLEL
 462      regions.  This appears to be implied by the semantics of
 463      threadprivate variables, but perhaps that's reading too much into
 464      things.  Certainly it does prevent any locking problems, since
 465      only the initial program thread will modify gomp_threads.  */
 466   if (!nested)
 467     {
 468       old_threads_used = pool->threads_used;
 469
 470       if (nthreads <= old_threads_used)
 471         n = nthreads;
 472       else if (old_threads_used == 0)
 473         {
 474           n = 0;
 475           gomp_simple_barrier_init (&pool->threads_dock, nthreads);
 476         }
 477       else
 478         {
 479           n = old_threads_used;
 480
 481           /* Increase the barrier threshold to make sure all new
 482              threads arrive before the team is released.  */
 483           gomp_simple_barrier_reinit (&pool->threads_dock, nthreads);
 484         }
 485
 486       /* Not true yet, but soon will be.  We're going to release all
 487          threads from the dock, and those that aren't part of the
 488          team will exit.  */
 489       pool->threads_used = nthreads;
 490
 491       /* If necessary, expand the size of the gomp_threads array.  It is
 492          expected that changes in the number of threads are rare, thus we
 493          make no effort to expand gomp_threads_size geometrically.  */
 494       if (nthreads >= pool->threads_size)
 495         {
 496           pool->threads_size = nthreads + 1;
 497           pool->threads
 498             = gomp_realloc (pool->threads,
 499                             pool->threads_size
 500                             * sizeof (struct gomp_thread *));
 501           /* Add current (master) thread to threads[].  */
 502           pool->threads[0] = thr;
 503         }
 504
 505       /* Release existing idle threads.  */
 506       for (; i < n; ++i)
 507         {
 508           unsigned int place_partition_off = thr->ts.place_partition_off;
 509           unsigned int place_partition_len = thr->ts.place_partition_len;
 510           unsigned int place = 0;
 511           if (__builtin_expect (gomp_places_list != NULL, 0))
 512             {
 513               switch (bind)
 514                 {
 515                 case omp_proc_bind_true:
 516                 case omp_proc_bind_close:
 517                   if (k == s)
 518                     {
 519                       ++p;
 520                       if (p == (team->prev_ts.place_partition_off
 521                                 + team->prev_ts.place_partition_len))
 522                         p = team->prev_ts.place_partition_off;
 523                       k = 1;
 524                       if (i == nthreads - rest)
 525                         s = 1;
 526                     }
 527                   else
 528                     ++k;
 529                   break;
 530                 case omp_proc_bind_master:
 531                   break;
 532                 case omp_proc_bind_spread:
 533                   if (k == 0)
 534                     {
 535                       /* T <= P.  */
 536                       if (p < rest)
 537                         p += s + 1;
 538                       else
 539                         p += s;
 540                       if (p == (team->prev_ts.place_partition_off
 541                                 + team->prev_ts.place_partition_len))
 542                         p = team->prev_ts.place_partition_off;
 543                       place_partition_off = p;
 544                       if (p < rest)
 545                         place_partition_len = s + 1;
 546                       else
 547                         place_partition_len = s;
 548                     }
 549                   else
 550                     {
 551                       /* T > P.  */
 552                       if (k == s)
 553                         {
 554                           ++p;
 555                           if (p == (team->prev_ts.place_partition_off
 556                                     + team->prev_ts.place_partition_len))
 557                             p = team->prev_ts.place_partition_off;
 558                           k = 1;
 559                           if (i == nthreads - rest)
 560                             s = 1;
 561                         }
 562                       else
 563                         ++k;
 564                       place_partition_off = p;
 565                       place_partition_len = 1;
 566                     }
 567                   break;
 568                 }
 569               if (affinity_thr != NULL
 570                   || (bind != omp_proc_bind_true
 571                       && pool->threads[i]->place != p + 1)
 572                   || pool->threads[i]->place <= place_partition_off
 573                   || pool->threads[i]->place > (place_partition_off
 574                                                 + place_partition_len))
 575                 {
 576                   unsigned int l;
 577                   force_display = true;
 578                   if (affinity_thr == NULL)
 579                     {
 580                       unsigned int j;
 581
 582                       if (team->prev_ts.place_partition_len > 64)
 583                         affinity_thr
 584                           = gomp_malloc (team->prev_ts.place_partition_len
 585                                          * sizeof (struct gomp_thread *));
 586                       else
 587                         affinity_thr
 588                           = gomp_alloca (team->prev_ts.place_partition_len
 589                                          * sizeof (struct gomp_thread *));
 590                       memset (affinity_thr, '\0',
 591                               team->prev_ts.place_partition_len
 592                               * sizeof (struct gomp_thread *));
 593                       for (j = i; j < old_threads_used; j++)
 594                         {
 595                           if (pool->threads[j]->place
 596                               > team->prev_ts.place_partition_off
 597                               && (pool->threads[j]->place
 598                                   <= (team->prev_ts.place_partition_off
 599                                       + team->prev_ts.place_partition_len)))
 600                             {
 601                               l = pool->threads[j]->place - 1
 602                                   - team->prev_ts.place_partition_off;
 603                               pool->threads[j]->data = affinity_thr[l];
 604                               affinity_thr[l] = pool->threads[j];
 605                             }
 606                           pool->threads[j] = NULL;
 607                         }
 608                       if (nthreads > old_threads_used)
 609                         memset (&pool->threads[old_threads_used],
 610                                 '\0', ((nthreads - old_threads_used)
 611                                        * sizeof (struct gomp_thread *)));
 612                       n = nthreads;
 613                       affinity_count = old_threads_used - i;
 614                     }
 615                   if (affinity_count == 0)
 616                     break;
 617                   l = p;
 618                   if (affinity_thr[l - team->prev_ts.place_partition_off]
 619                       == NULL)
 620                     {
 621                       if (bind != omp_proc_bind_true)
 622                         continue;
 623                       for (l = place_partition_off;
 624                            l < place_partition_off + place_partition_len;
 625                            l++)
 626                         if (affinity_thr[l - team->prev_ts.place_partition_off]
 627                             != NULL)
 628                           break;
 629                       if (l == place_partition_off + place_partition_len)
 630                         continue;
 631                     }
 632                   nthr = affinity_thr[l - team->prev_ts.place_partition_off];
 633                   affinity_thr[l - team->prev_ts.place_partition_off]
 634                     = (struct gomp_thread *) nthr->data;
 635                   affinity_count--;
 636                   pool->threads[i] = nthr;
 637                 }
 638               else
 639                 nthr = pool->threads[i];
 640               place = p + 1;
 641             }
 642           else
 643             nthr = pool->threads[i];
 644           nthr->ts.team = team;
 645           nthr->ts.work_share = &team->work_shares[0];
 646           nthr->ts.last_work_share = NULL;
 647           nthr->ts.team_id = i;
 648           nthr->ts.level = team->prev_ts.level + 1;
 649           nthr->ts.active_level = thr->ts.active_level;
 650           nthr->ts.place_partition_off = place_partition_off;
 651           nthr->ts.place_partition_len = place_partition_len;
 652           nthr->ts.def_allocator = thr->ts.def_allocator;
 653 #ifdef HAVE_SYNC_BUILTINS
 654           nthr->ts.single_count = 0;
 655 #endif
 656           nthr->ts.static_trip = 0;
 657           nthr->num_teams = thr->num_teams;
 658           nthr->team_num = thr->team_num;
 659           nthr->task = &team->implicit_task[i];
 660           nthr->place = place;
 661           gomp_init_task (nthr->task, task, icv);
 662           team->implicit_task[i].icv.nthreads_var = nthreads_var;
 663           team->implicit_task[i].icv.bind_var = bind_var;
 664           nthr->task->taskgroup = taskgroup;
 665           nthr->fn = fn;
 666           nthr->data = data;
 667           team->ordered_release[i] = &nthr->release;
 668         }
 669
 670       if (__builtin_expect (affinity_thr != NULL, 0))
 671         {
 672           /* If AFFINITY_THR is non-NULL just because we had to
 673              permute some threads in the pool, but we've managed
 674              to find exactly as many old threads as we'd find
 675              without affinity, we don't need to handle this
 676              specially anymore.  */
 677           if (nthreads <= old_threads_used
 678               ? (affinity_count == old_threads_used - nthreads)
 679               : (i == old_threads_used))
 680             {
 681               if (team->prev_ts.place_partition_len > 64)
 682                 free (affinity_thr);
 683               affinity_thr = NULL;
 684               affinity_count = 0;
 685             }
 686           else
 687             {
 688               i = 1;
 689               /* We are going to compute the places/subpartitions
 690                  again from the beginning.  So, we need to reinitialize
 691                  vars modified by the switch (bind) above inside
 692                  of the loop, to the state they had after the initial
 693                  switch (bind).  */
 694               switch (bind)
 695                 {
 696                 case omp_proc_bind_true:
 697                 case omp_proc_bind_close:
 698                   if (nthreads > thr->ts.place_partition_len)
 699                     /* T > P.  S has been changed, so needs
 700                        to be recomputed.  */
 701                     s = nthreads / thr->ts.place_partition_len;
 702                   k = 1;
 703                   p = thr->place - 1;
 704                   break;
 705                 case omp_proc_bind_master:
 706                   /* No vars have been changed.  */
 707                   break;
 708                 case omp_proc_bind_spread:
 709                   p = thr->ts.place_partition_off;
 710                   if (k != 0)
 711                     {
 712                       /* T > P.  */
 713                       s = nthreads / team->prev_ts.place_partition_len;
 714                       k = 1;
 715                     }
 716                   break;
 717                 }
 718
 719               /* Increase the barrier threshold to make sure all new
 720                  threads and all the threads we're going to let die
 721                  arrive before the team is released.  */
 722               if (affinity_count)
 723                 gomp_simple_barrier_reinit (&pool->threads_dock,
 724                                             nthreads + affinity_count);
 725             }
 726         }
 727
 728       if (i == nthreads)
 729         goto do_release;
 730
 731     }
 732
 733   if (__builtin_expect (nthreads + affinity_count > old_threads_used, 0))
 734     {
 735       long diff = (long) (nthreads + affinity_count) - (long) old_threads_used;
 736
 737       if (old_threads_used == 0)
 738         --diff;
 739
 740 #ifdef HAVE_SYNC_BUILTINS
 741       __sync_fetch_and_add (&gomp_managed_threads, diff);
 742 #else
 743       gomp_mutex_lock (&gomp_managed_threads_lock);
 744       gomp_managed_threads += diff;
 745       gomp_mutex_unlock (&gomp_managed_threads_lock);
 746 #endif
 747     }
 748
 749   attr = &gomp_thread_attr;
 750   if (__builtin_expect (gomp_places_list != NULL, 0))
 751     {
 752       size_t stacksize;
 753       pthread_attr_init (&thread_attr);
 754       if (! pthread_attr_getstacksize (&gomp_thread_attr, &stacksize))
 755         pthread_attr_setstacksize (&thread_attr, stacksize);
 756       attr = &thread_attr;
 757     }
 758
 759   start_data = gomp_alloca (sizeof (struct gomp_thread_start_data)
 760                             * (nthreads - i));
 761
 762   /* Launch new threads.  */
 763   for (; i < nthreads; ++i)
 764     {
 765       int err;
 766
 767       start_data->ts.place_partition_off = thr->ts.place_partition_off;
 768       start_data->ts.place_partition_len = thr->ts.place_partition_len;
 769       start_data->place = 0;
 770       if (__builtin_expect (gomp_places_list != NULL, 0))
 771         {
 772           switch (bind)
 773             {
 774             case omp_proc_bind_true:
 775             case omp_proc_bind_close:
 776               if (k == s)
 777                 {
 778                   ++p;
 779                   if (p == (team->prev_ts.place_partition_off
 780                             + team->prev_ts.place_partition_len))
 781                     p = team->prev_ts.place_partition_off;
 782                   k = 1;
 783                   if (i == nthreads - rest)
 784                     s = 1;
 785                 }
 786               else
 787                 ++k;
 788               break;
 789             case omp_proc_bind_master:
 790               break;
 791             case omp_proc_bind_spread:
 792               if (k == 0)
 793                 {
 794                   /* T <= P.  */
 795                   if (p < rest)
 796                     p += s + 1;
 797                   else
 798                     p += s;
 799                   if (p == (team->prev_ts.place_partition_off
 800                             + team->prev_ts.place_partition_len))
 801                     p = team->prev_ts.place_partition_off;
 802                   start_data->ts.place_partition_off = p;
 803                   if (p < rest)
 804                     start_data->ts.place_partition_len = s + 1;
 805                   else
 806                     start_data->ts.place_partition_len = s;
 807                 }
 808               else
 809                 {
 810                   /* T > P.  */
 811                   if (k == s)
 812                     {
 813                       ++p;
 814                       if (p == (team->prev_ts.place_partition_off
 815                                 + team->prev_ts.place_partition_len))
 816                         p = team->prev_ts.place_partition_off;
 817                       k = 1;
 818                       if (i == nthreads - rest)
 819                         s = 1;
 820                     }
 821                   else
 822                     ++k;
 823                   start_data->ts.place_partition_off = p;
 824                   start_data->ts.place_partition_len = 1;
 825                 }
 826               break;
 827             }
 828           start_data->place = p + 1;
 829           if (affinity_thr != NULL && pool->threads[i] != NULL)
 830             continue;
 831           gomp_init_thread_affinity (attr, p);
 832         }
 833
 834       start_data->fn = fn;
 835       start_data->fn_data = data;
 836       start_data->ts.team = team;
 837       start_data->ts.work_share = &team->work_shares[0];
 838       start_data->ts.last_work_share = NULL;
 839       start_data->ts.team_id = i;
 840       start_data->ts.level = team->prev_ts.level + 1;
 841       start_data->ts.active_level = thr->ts.active_level;
 842       start_data->ts.def_allocator = thr->ts.def_allocator;
 843 #ifdef HAVE_SYNC_BUILTINS
 844       start_data->ts.single_count = 0;
 845 #endif
 846       start_data->ts.static_trip = 0;
 847       start_data->num_teams = thr->num_teams;
 848       start_data->team_num = thr->team_num;
 849       start_data->task = &team->implicit_task[i];
 850       gomp_init_task (start_data->task, task, icv);
 851       team->implicit_task[i].icv.nthreads_var = nthreads_var;
 852       team->implicit_task[i].icv.bind_var = bind_var;
 853       start_data->task->taskgroup = taskgroup;
 854       start_data->thread_pool = pool;
 855       start_data->nested = nested;
 856
 857       attr = gomp_adjust_thread_attr (attr, &thread_attr);
 858       err = pthread_create (&start_data->handle, attr, gomp_thread_start,
 859                             start_data);
 860       start_data++;
 861       if (err != 0)
 862         gomp_fatal ("Thread creation failed: %s", strerror (err));
 863     }
 864
 865   if (__builtin_expect (attr == &thread_attr, 0))
 866     pthread_attr_destroy (&thread_attr);
 867
 868  do_release:
 869   if (nested)
 870     gomp_barrier_wait (&team->barrier);
 871   else
 872     gomp_simple_barrier_wait (&pool->threads_dock);
 873
 874   /* Decrease the barrier threshold to match the number of threads
 875      that should arrive back at the end of this team.  The extra
 876      threads should be exiting.  Note that we arrange for this test
 877      to never be true for nested teams.  If AFFINITY_COUNT is non-zero,
 878      the barrier as well as gomp_managed_threads was temporarily
 879      set to NTHREADS + AFFINITY_COUNT.  For NTHREADS < OLD_THREADS_COUNT,
 880      AFFINITY_COUNT if non-zero will be always at least
 881      OLD_THREADS_COUNT - NTHREADS.  */
 882   if (__builtin_expect (nthreads < old_threads_used, 0)
 883       || __builtin_expect (affinity_count, 0))
 884     {
 885       long diff = (long) nthreads - (long) old_threads_used;
 886
 887       if (affinity_count)
 888         diff = -affinity_count;
 889
 890       gomp_simple_barrier_reinit (&pool->threads_dock, nthreads);
 891
 892 #ifdef HAVE_SYNC_BUILTINS
 893       __sync_fetch_and_add (&gomp_managed_threads, diff);
 894 #else
 895       gomp_mutex_lock (&gomp_managed_threads_lock);
 896       gomp_managed_threads += diff;
 897       gomp_mutex_unlock (&gomp_managed_threads_lock);
 898 #endif
 899     }
 900   if (__builtin_expect (gomp_display_affinity_var, 0))
 901     {
 902       if (nested
 903           || nthreads != old_threads_used
 904           || force_display)
 905         {
 906           gomp_display_affinity_thread (gomp_thread_self (), &thr->ts,
 907                                         thr->place);
 908           if (nested)
 909             {
 910               start_data -= nthreads - 1;
 911               for (i = 1; i < nthreads; ++i)
 912                 {
 913                   gomp_display_affinity_thread (
 914 #ifdef LIBGOMP_USE_PTHREADS
 915                                                 start_data->handle,
 916 #else
 917                                                 gomp_thread_self (),
 918 #endif
 919                                                 &start_data->ts,
 920                                                 start_data->place);
 921                   start_data++;
 922                 }
 923             }
 924           else
 925             {
 926               for (i = 1; i < nthreads; ++i)
 927                 {
 928                   gomp_thread_handle handle
 929                     = gomp_thread_to_pthread_t (pool->threads[i]);
 930                   gomp_display_affinity_thread (handle, &pool->threads[i]->ts,
 931                                                 pool->threads[i]->place);
 932                 }
 933             }
 934         }
 935     }
 936   if (__builtin_expect (affinity_thr != NULL, 0)
 937       && team->prev_ts.place_partition_len > 64)
 938     free (affinity_thr);
 939 }
 940 #endif
 941
 942
 943 /* Terminate the current team.  This is only to be called by the master
 944    thread.  We assume that we must wait for the other threads.  */
 945
 946 void
 947 gomp_team_end (void)
 948 {
 949   struct gomp_thread *thr = gomp_thread ();
 950   struct gomp_team *team = thr->ts.team;
 951
 952   /* This barrier handles all pending explicit threads.
 953      As #pragma omp cancel parallel might get awaited count in
 954      team->barrier in a inconsistent state, we need to use a different
 955      counter here.  */
 956   gomp_team_barrier_wait_final (&team->barrier);
 957   if (__builtin_expect (team->team_cancelled, 0))
 958     {
 959       struct gomp_work_share *ws = team->work_shares_to_free;
 960       do
 961         {
 962           struct gomp_work_share *next_ws = gomp_ptrlock_get (&ws->next_ws);
 963           if (next_ws == NULL)
 964             gomp_ptrlock_set (&ws->next_ws, ws);
 965           gomp_fini_work_share (ws);
 966           ws = next_ws;
 967         }
 968       while (ws != NULL);
 969     }
 970   else
 971     gomp_fini_work_share (thr->ts.work_share);
 972
 973   gomp_end_task ();
 974   thr->ts = team->prev_ts;
 975
 976   if (__builtin_expect (thr->ts.level != 0, 0))
 977     {
 978 #ifdef HAVE_SYNC_BUILTINS
 979       __sync_fetch_and_add (&gomp_managed_threads, 1L - team->nthreads);
 980 #else
 981       gomp_mutex_lock (&gomp_managed_threads_lock);
 982       gomp_managed_threads -= team->nthreads - 1L;
 983       gomp_mutex_unlock (&gomp_managed_threads_lock);
 984 #endif
 985       /* This barrier has gomp_barrier_wait_last counterparts
 986          and ensures the team can be safely destroyed.  */
 987       gomp_barrier_wait (&team->barrier);
 988     }
 989
 990   if (__builtin_expect (team->work_shares[0].next_alloc != NULL, 0))
 991     {
 992       struct gomp_work_share *ws = team->work_shares[0].next_alloc;
 993       do
 994         {
 995           struct gomp_work_share *next_ws = ws->next_alloc;
 996           free (ws);
 997           ws = next_ws;
 998         }
 999       while (ws != NULL);
1000     }
1001   gomp_sem_destroy (&team->master_release);
1002
1003   if (__builtin_expect (thr->ts.team != NULL, 0)
1004       || __builtin_expect (team->nthreads == 1, 0))
1005     free_team (team);
1006   else
1007     {
1008       struct gomp_thread_pool *pool = thr->thread_pool;
1009       if (pool->last_team)
1010         free_team (pool->last_team);
1011       pool->last_team = team;
1012       gomp_release_thread_pool (pool);
1013     }
1014 }
1015
1016 #ifdef LIBGOMP_USE_PTHREADS
1017
1018 /* Constructors for this file.  */
1019
1020 static void __attribute__((constructor))
1021 initialize_team (void)
1022 {
1023 #if !defined HAVE_TLS && !defined USE_EMUTLS
1024   static struct gomp_thread initial_thread_tls_data;
1025
1026   pthread_key_create (&gomp_tls_key, NULL);
1027   pthread_setspecific (gomp_tls_key, &initial_thread_tls_data);
1028 #endif
1029
1030   if (pthread_key_create (&gomp_thread_destructor, gomp_free_thread) != 0)
1031     gomp_fatal ("could not create thread pool destructor.");
1032 }
1033
1034 static void __attribute__((destructor))
1035 team_destructor (void)
1036 {
1037   /* Without this dlclose on libgomp could lead to subsequent
1038      crashes.  */
1039   pthread_key_delete (gomp_thread_destructor);
1040 }
1041
1042 /* Similar to gomp_free_pool_helper, but don't detach itself,
1043    gomp_pause_host will pthread_join those threads.  */
1044
1045 static void
1046 gomp_pause_pool_helper (void *thread_pool)
1047 {
1048   struct gomp_thread *thr = gomp_thread ();
1049   struct gomp_thread_pool *pool
1050     = (struct gomp_thread_pool *) thread_pool;
1051   gomp_simple_barrier_wait_last (&pool->threads_dock);
1052   gomp_sem_destroy (&thr->release);
1053   thr->thread_pool = NULL;
1054   thr->task = NULL;
1055   pthread_exit (NULL);
1056 }
1057
1058 /* Free a thread pool and release its threads.  Return non-zero on
1059    failure.  */
1060
1061 int
1062 gomp_pause_host (void)
1063 {
1064   struct gomp_thread *thr = gomp_thread ();
1065   struct gomp_thread_pool *pool = thr->thread_pool;
1066   if (thr->ts.level)
1067     return -1;
1068   if (pool)
1069     {
1070       if (pool->threads_used > 0)
1071         {
1072           int i;
1073           pthread_t *thrs
1074             = gomp_alloca (sizeof (pthread_t) * pool->threads_used);
1075           for (i = 1; i < pool->threads_used; i++)
1076             {
1077               struct gomp_thread *nthr = pool->threads[i];
1078               nthr->fn = gomp_pause_pool_helper;
1079               nthr->data = pool;
1080               thrs[i] = gomp_thread_to_pthread_t (nthr);
1081             }
1082           /* This barrier undocks threads docked on pool->threads_dock.  */
1083           gomp_simple_barrier_wait (&pool->threads_dock);
1084           /* And this waits till all threads have called gomp_barrier_wait_last
1085              in gomp_pause_pool_helper.  */
1086           gomp_simple_barrier_wait (&pool->threads_dock);
1087           /* Now it is safe to destroy the barrier and free the pool.  */
1088           gomp_simple_barrier_destroy (&pool->threads_dock);
1089
1090 #ifdef HAVE_SYNC_BUILTINS
1091           __sync_fetch_and_add (&gomp_managed_threads,
1092                                 1L - pool->threads_used);
1093 #else
1094           gomp_mutex_lock (&gomp_managed_threads_lock);
1095           gomp_managed_threads -= pool->threads_used - 1L;
1096           gomp_mutex_unlock (&gomp_managed_threads_lock);
1097 #endif
1098           for (i = 1; i < pool->threads_used; i++)
1099             pthread_join (thrs[i], NULL);
1100         }
1101       if (pool->last_team)
1102         free_team (pool->last_team);
1103 #ifndef __nvptx__
1104       team_free (pool->threads);
1105       team_free (pool);
1106 #endif
1107       thr->thread_pool = NULL;
1108     }
1109   return 0;
1110 }
1111 #endif
1112
1113 struct gomp_task_icv *
1114 gomp_new_icv (void)
1115 {
1116   struct gomp_thread *thr = gomp_thread ();
1117   struct gomp_task *task = gomp_malloc (sizeof (struct gomp_task));
1118   gomp_init_task (task, NULL, &gomp_global_icv);
1119   thr->task = task;
1120 #ifdef LIBGOMP_USE_PTHREADS
1121   pthread_setspecific (gomp_thread_destructor, thr);
1122 #endif
1123   return &task->icv;
1124 }