libgomp/oacc-init.c

   1 /* OpenACC Runtime initialization routines
   2
   3    Copyright (C) 2013-2015 Free Software Foundation, Inc.
   4
   5    Contributed by Mentor Embedded.
   6
   7    This file is part of the GNU Offloading and Multi Processing Library
   8    (libgomp).
   9
  10    Libgomp is free software; you can redistribute it and/or modify it
  11    under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 3, or (at your option)
  13    any later version.
  14
  15    Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
  16    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  17    FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  18    more details.
  19
  20    Under Section 7 of GPL version 3, you are granted additional
  21    permissions described in the GCC Runtime Library Exception, version
  22    3.1, as published by the Free Software Foundation.
  23
  24    You should have received a copy of the GNU General Public License and
  25    a copy of the GCC Runtime Library Exception along with this program;
  26    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  27    <http://www.gnu.org/licenses/>.  */
  28
  29 #include "libgomp.h"
  30 #include "oacc-int.h"
  31 #include "openacc.h"
  32 #include <assert.h>
  33 #include <stdlib.h>
  34 #include <strings.h>
  35 #include <stdbool.h>
  36 #include <string.h>
  37
  38 /* This lock is used to protect access to cached_base_dev, dispatchers and
  39    the (abstract) initialisation state of attached offloading devices.  */
  40
  41 static gomp_mutex_t acc_device_lock;
  42
  43 /* A cached version of the dispatcher for the global "current" accelerator type,
  44    e.g. used as the default when creating new host threads.  This is the
  45    device-type equivalent of goacc_device_num (which specifies which device to
  46    use out of potentially several of the same type).  If there are several
  47    devices of a given type, this points at the first one.  */
  48
  49 static struct gomp_device_descr *cached_base_dev = NULL;
  50
  51 #if defined HAVE_TLS || defined USE_EMUTLS
  52 __thread struct goacc_thread *goacc_tls_data;
  53 #else
  54 pthread_key_t goacc_tls_key;
  55 #endif
  56 static pthread_key_t goacc_cleanup_key;
  57
  58 static struct goacc_thread *goacc_threads;
  59 static gomp_mutex_t goacc_thread_lock;
  60
  61 /* An array of dispatchers for device types, indexed by the type.  This array
  62    only references "base" devices, and other instances of the same type are
  63    found by simply indexing from each such device (which are stored linearly,
  64    grouped by device in target.c:devices).  */
  65 static struct gomp_device_descr *dispatchers[_ACC_device_hwm] = { 0 };
  66
  67 attribute_hidden void
  68 goacc_register (struct gomp_device_descr *disp)
  69 {
  70   /* Only register the 0th device here.  */
  71   if (disp->target_id != 0)
  72     return;
  73
  74   gomp_mutex_lock (&acc_device_lock);
  75
  76   assert (acc_device_type (disp->type) != acc_device_none
  77           && acc_device_type (disp->type) != acc_device_default
  78           && acc_device_type (disp->type) != acc_device_not_host);
  79   assert (!dispatchers[disp->type]);
  80   dispatchers[disp->type] = disp;
  81
  82   gomp_mutex_unlock (&acc_device_lock);
  83 }
  84
  85 /* OpenACC names some things a little differently.  */
  86
  87 static const char *
  88 get_openacc_name (const char *name)
  89 {
  90   if (strcmp (name, "nvptx") == 0)
  91     return "nvidia";
  92   else
  93     return name;
  94 }
  95
  96 static const char *
  97 name_of_acc_device_t (enum acc_device_t type)
  98 {
  99   switch (type)
 100     {
 101     case acc_device_none: return "none";
 102     case acc_device_default: return "default";
 103     case acc_device_host: return "host";
 104     case acc_device_not_host: return "not_host";
 105     case acc_device_nvidia: return "nvidia";
 106     default: gomp_fatal ("unknown device type %u", (unsigned) type);
 107     }
 108 }
 109
 110 /* ACC_DEVICE_LOCK must be held before calling this function.  If FAIL_IS_ERROR
 111    is true, this function raises an error if there are no devices of type D,
 112    otherwise it returns NULL in that case.  */
 113
 114 static struct gomp_device_descr *
 115 resolve_device (acc_device_t d, bool fail_is_error)
 116 {
 117   acc_device_t d_arg = d;
 118
 119   switch (d)
 120     {
 121     case acc_device_default:
 122       {
 123         if (goacc_device_type)
 124           {
 125             /* Lookup the named device.  */
 126             while (++d != _ACC_device_hwm)
 127               if (dispatchers[d]
 128                   && !strcasecmp (goacc_device_type,
 129                                   get_openacc_name (dispatchers[d]->name))
 130                   && dispatchers[d]->get_num_devices_func () > 0)
 131                 goto found;
 132
 133             if (fail_is_error)
 134               {
 135                 gomp_mutex_unlock (&acc_device_lock);
 136                 gomp_fatal ("device type %s not supported", goacc_device_type);
 137               }
 138             else
 139               return NULL;
 140           }
 141
 142         /* No default device specified, so start scanning for any non-host
 143            device that is available.  */
 144         d = acc_device_not_host;
 145       }
 146       /* FALLTHROUGH */
 147
 148     case acc_device_not_host:
 149       /* Find the first available device after acc_device_not_host.  */
 150       while (++d != _ACC_device_hwm)
 151         if (dispatchers[d] && dispatchers[d]->get_num_devices_func () > 0)
 152           goto found;
 153       if (d_arg == acc_device_default)
 154         {
 155           d = acc_device_host;
 156           goto found;
 157         }
 158       if (fail_is_error)
 159         {
 160           gomp_mutex_unlock (&acc_device_lock);
 161           gomp_fatal ("no device found");
 162         }
 163       else
 164         return NULL;
 165       break;
 166
 167     case acc_device_host:
 168       break;
 169
 170     default:
 171       if (d > _ACC_device_hwm)
 172         {
 173           if (fail_is_error)
 174             goto unsupported_device;
 175           else
 176             return NULL;
 177         }
 178       break;
 179     }
 180  found:
 181
 182   assert (d != acc_device_none
 183           && d != acc_device_default
 184           && d != acc_device_not_host);
 185
 186   if (dispatchers[d] == NULL && fail_is_error)
 187     {
 188     unsupported_device:
 189       gomp_mutex_unlock (&acc_device_lock);
 190       gomp_fatal ("device type %s not supported", name_of_acc_device_t (d));
 191     }
 192
 193   return dispatchers[d];
 194 }
 195
 196 /* Emit a suitable error if no device of a particular type is available, or
 197    the given device number is out-of-range.  */
 198 static void
 199 acc_dev_num_out_of_range (acc_device_t d, int ord, int ndevs)
 200 {
 201   if (ndevs == 0)
 202     gomp_fatal ("no devices of type %s available", name_of_acc_device_t (d));
 203   else
 204     gomp_fatal ("device %u out of range", ord);
 205 }
 206
 207 /* This is called when plugins have been initialized, and serves to call
 208    (indirectly) the target's device_init hook.  Calling multiple times without
 209    an intervening acc_shutdown_1 call is an error.  ACC_DEVICE_LOCK must be
 210    held before calling this function.  */
 211
 212 static struct gomp_device_descr *
 213 acc_init_1 (acc_device_t d)
 214 {
 215   struct gomp_device_descr *base_dev, *acc_dev;
 216   int ndevs;
 217
 218   base_dev = resolve_device (d, true);
 219
 220   ndevs = base_dev->get_num_devices_func ();
 221
 222   if (ndevs <= 0 || goacc_device_num >= ndevs)
 223     acc_dev_num_out_of_range (d, goacc_device_num, ndevs);
 224
 225   acc_dev = &base_dev[goacc_device_num];
 226
 227   gomp_mutex_lock (&acc_dev->lock);
 228   if (acc_dev->is_initialized)
 229     {
 230       gomp_mutex_unlock (&acc_dev->lock);
 231       gomp_fatal ("device already active");
 232     }
 233
 234   gomp_init_device (acc_dev);
 235   gomp_mutex_unlock (&acc_dev->lock);
 236
 237   return base_dev;
 238 }
 239
 240 /* ACC_DEVICE_LOCK must be held before calling this function.  */
 241
 242 static void
 243 acc_shutdown_1 (acc_device_t d)
 244 {
 245   struct gomp_device_descr *base_dev;
 246   struct goacc_thread *walk;
 247   int ndevs, i;
 248   bool devices_active = false;
 249
 250   /* Get the base device for this device type.  */
 251   base_dev = resolve_device (d, true);
 252
 253   ndevs = base_dev->get_num_devices_func ();
 254
 255   /* Unload all the devices of this type that have been opened.  */
 256   for (i = 0; i < ndevs; i++)
 257     {
 258       struct gomp_device_descr *acc_dev = &base_dev[i];
 259
 260       gomp_mutex_lock (&acc_dev->lock);
 261       gomp_unload_device (acc_dev);
 262       gomp_mutex_unlock (&acc_dev->lock);
 263     }
 264
 265   gomp_mutex_lock (&goacc_thread_lock);
 266
 267   /* Free target-specific TLS data and close all devices.  */
 268   for (walk = goacc_threads; walk != NULL; walk = walk->next)
 269     {
 270       if (walk->target_tls)
 271         base_dev->openacc.destroy_thread_data_func (walk->target_tls);
 272
 273       walk->target_tls = NULL;
 274
 275       /* This would mean the user is shutting down OpenACC in the middle of an
 276          "acc data" pragma.  Likely not intentional.  */
 277       if (walk->mapped_data)
 278         {
 279           gomp_mutex_unlock (&goacc_thread_lock);
 280           gomp_fatal ("shutdown in 'acc data' region");
 281         }
 282
 283       /* Similarly, if this happens then user code has done something weird.  */
 284       if (walk->saved_bound_dev)
 285         {
 286           gomp_mutex_unlock (&goacc_thread_lock);
 287           gomp_fatal ("shutdown during host fallback");
 288         }
 289
 290       if (walk->dev)
 291         {
 292           gomp_mutex_lock (&walk->dev->lock);
 293           gomp_free_memmap (&walk->dev->mem_map);
 294           gomp_mutex_unlock (&walk->dev->lock);
 295
 296           walk->dev = NULL;
 297           walk->base_dev = NULL;
 298         }
 299     }
 300
 301   gomp_mutex_unlock (&goacc_thread_lock);
 302
 303
 304   /* Close all the devices of this type that have been opened.  */
 305   for (i = 0; i < ndevs; i++)
 306     {
 307       struct gomp_device_descr *acc_dev = &base_dev[i];
 308       gomp_mutex_lock (&acc_dev->lock);
 309       if (acc_dev->is_initialized)
 310         {
 311           devices_active = true;
 312           gomp_fini_device (acc_dev);
 313         }
 314       gomp_mutex_unlock (&acc_dev->lock);
 315     }
 316
 317   if (!devices_active)
 318     gomp_fatal ("no device initialized");
 319 }
 320
 321 static struct goacc_thread *
 322 goacc_new_thread (void)
 323 {
 324   struct goacc_thread *thr = gomp_malloc (sizeof (struct gomp_thread));
 325
 326 #if defined HAVE_TLS || defined USE_EMUTLS
 327   goacc_tls_data = thr;
 328 #else
 329   pthread_setspecific (goacc_tls_key, thr);
 330 #endif
 331
 332   pthread_setspecific (goacc_cleanup_key, thr);
 333
 334   gomp_mutex_lock (&goacc_thread_lock);
 335   thr->next = goacc_threads;
 336   goacc_threads = thr;
 337   gomp_mutex_unlock (&goacc_thread_lock);
 338
 339   return thr;
 340 }
 341
 342 static void
 343 goacc_destroy_thread (void *data)
 344 {
 345   struct goacc_thread *thr = data, *walk, *prev;
 346
 347   gomp_mutex_lock (&goacc_thread_lock);
 348
 349   if (thr)
 350     {
 351       struct gomp_device_descr *acc_dev = thr->dev;
 352
 353       if (acc_dev && thr->target_tls)
 354         {
 355           acc_dev->openacc.destroy_thread_data_func (thr->target_tls);
 356           thr->target_tls = NULL;
 357         }
 358
 359       assert (!thr->mapped_data);
 360
 361       /* Remove from thread list.  */
 362       for (prev = NULL, walk = goacc_threads; walk;
 363            prev = walk, walk = walk->next)
 364         if (walk == thr)
 365           {
 366             if (prev == NULL)
 367               goacc_threads = walk->next;
 368             else
 369               prev->next = walk->next;
 370
 371             free (thr);
 372
 373             break;
 374           }
 375
 376       assert (walk);
 377     }
 378
 379   gomp_mutex_unlock (&goacc_thread_lock);
 380 }
 381
 382 /* Use the ORD'th device instance for the current host thread (or -1 for the
 383    current global default).  The device (and the runtime) must be initialised
 384    before calling this function.  */
 385
 386 void
 387 goacc_attach_host_thread_to_device (int ord)
 388 {
 389   struct goacc_thread *thr = goacc_thread ();
 390   struct gomp_device_descr *acc_dev = NULL, *base_dev = NULL;
 391   int num_devices;
 392
 393   if (thr && thr->dev && (thr->dev->target_id == ord || ord < 0))
 394     return;
 395
 396   if (ord < 0)
 397     ord = goacc_device_num;
 398
 399   /* Decide which type of device to use.  If the current thread has a device
 400      type already (e.g. set by acc_set_device_type), use that, else use the
 401      global default.  */
 402   if (thr && thr->base_dev)
 403     base_dev = thr->base_dev;
 404   else
 405     {
 406       assert (cached_base_dev);
 407       base_dev = cached_base_dev;
 408     }
 409
 410   num_devices = base_dev->get_num_devices_func ();
 411   if (num_devices <= 0 || ord >= num_devices)
 412     acc_dev_num_out_of_range (acc_device_type (base_dev->type), ord,
 413                               num_devices);
 414
 415   if (!thr)
 416     thr = goacc_new_thread ();
 417
 418   thr->base_dev = base_dev;
 419   thr->dev = acc_dev = &base_dev[ord];
 420   thr->saved_bound_dev = NULL;
 421   thr->mapped_data = NULL;
 422
 423   thr->target_tls
 424     = acc_dev->openacc.create_thread_data_func (ord);
 425
 426   acc_dev->openacc.async_set_async_func (acc_async_sync);
 427 }
 428
 429 /* OpenACC 2.0a (3.2.12, 3.2.13) doesn't specify whether the serialization of
 430    init/shutdown is per-process or per-thread.  We choose per-process.  */
 431
 432 void
 433 acc_init (acc_device_t d)
 434 {
 435   if (!cached_base_dev)
 436     gomp_init_targets_once ();
 437
 438   gomp_mutex_lock (&acc_device_lock);
 439
 440   cached_base_dev = acc_init_1 (d);
 441
 442   gomp_mutex_unlock (&acc_device_lock);
 443
 444   goacc_attach_host_thread_to_device (-1);
 445 }
 446
 447 ialias (acc_init)
 448
 449 void
 450 acc_shutdown (acc_device_t d)
 451 {
 452   gomp_mutex_lock (&acc_device_lock);
 453
 454   acc_shutdown_1 (d);
 455
 456   gomp_mutex_unlock (&acc_device_lock);
 457 }
 458
 459 ialias (acc_shutdown)
 460
 461 int
 462 acc_get_num_devices (acc_device_t d)
 463 {
 464   int n = 0;
 465   struct gomp_device_descr *acc_dev;
 466
 467   if (d == acc_device_none)
 468     return 0;
 469
 470   gomp_init_targets_once ();
 471
 472   gomp_mutex_lock (&acc_device_lock);
 473   acc_dev = resolve_device (d, false);
 474   gomp_mutex_unlock (&acc_device_lock);
 475
 476   if (!acc_dev)
 477     return 0;
 478
 479   n = acc_dev->get_num_devices_func ();
 480   if (n < 0)
 481     n = 0;
 482
 483   return n;
 484 }
 485
 486 ialias (acc_get_num_devices)
 487
 488 /* Set the device type for the current thread only (using the current global
 489    default device number), initialising that device if necessary.  Also set the
 490    default device type for new threads to D.  */
 491
 492 void
 493 acc_set_device_type (acc_device_t d)
 494 {
 495   struct gomp_device_descr *base_dev, *acc_dev;
 496   struct goacc_thread *thr = goacc_thread ();
 497
 498   gomp_mutex_lock (&acc_device_lock);
 499
 500   if (!cached_base_dev)
 501     gomp_init_targets_once ();
 502
 503   cached_base_dev = base_dev = resolve_device (d, true);
 504   acc_dev = &base_dev[goacc_device_num];
 505
 506   gomp_mutex_lock (&acc_dev->lock);
 507   if (!acc_dev->is_initialized)
 508     gomp_init_device (acc_dev);
 509   gomp_mutex_unlock (&acc_dev->lock);
 510
 511   gomp_mutex_unlock (&acc_device_lock);
 512
 513   /* We're changing device type: invalidate the current thread's dev and
 514      base_dev pointers.  */
 515   if (thr && thr->base_dev != base_dev)
 516     {
 517       thr->base_dev = thr->dev = NULL;
 518       if (thr->mapped_data)
 519         gomp_fatal ("acc_set_device_type in 'acc data' region");
 520     }
 521
 522   goacc_attach_host_thread_to_device (-1);
 523 }
 524
 525 ialias (acc_set_device_type)
 526
 527 acc_device_t
 528 acc_get_device_type (void)
 529 {
 530   acc_device_t res = acc_device_none;
 531   struct gomp_device_descr *dev;
 532   struct goacc_thread *thr = goacc_thread ();
 533
 534   if (thr && thr->base_dev)
 535     res = acc_device_type (thr->base_dev->type);
 536   else
 537     {
 538       gomp_init_targets_once ();
 539
 540       gomp_mutex_lock (&acc_device_lock);
 541       dev = resolve_device (acc_device_default, true);
 542       gomp_mutex_unlock (&acc_device_lock);
 543       res = acc_device_type (dev->type);
 544     }
 545
 546   assert (res != acc_device_default
 547           && res != acc_device_not_host);
 548
 549   return res;
 550 }
 551
 552 ialias (acc_get_device_type)
 553
 554 int
 555 acc_get_device_num (acc_device_t d)
 556 {
 557   const struct gomp_device_descr *dev;
 558   struct goacc_thread *thr = goacc_thread ();
 559
 560   if (d >= _ACC_device_hwm)
 561     gomp_fatal ("unknown device type %u", (unsigned) d);
 562
 563   if (!cached_base_dev)
 564     gomp_init_targets_once ();
 565
 566   gomp_mutex_lock (&acc_device_lock);
 567   dev = resolve_device (d, true);
 568   gomp_mutex_unlock (&acc_device_lock);
 569
 570   if (thr && thr->base_dev == dev && thr->dev)
 571     return thr->dev->target_id;
 572
 573   return goacc_device_num;
 574 }
 575
 576 ialias (acc_get_device_num)
 577
 578 void
 579 acc_set_device_num (int ord, acc_device_t d)
 580 {
 581   struct gomp_device_descr *base_dev, *acc_dev;
 582   int num_devices;
 583
 584   if (!cached_base_dev)
 585     gomp_init_targets_once ();
 586
 587   if (ord < 0)
 588     ord = goacc_device_num;
 589
 590   if ((int) d == 0)
 591     /* Set whatever device is being used by the current host thread to use
 592        device instance ORD.  It's unclear if this is supposed to affect other
 593        host threads too (OpenACC 2.0 (3.2.4) acc_set_device_num).  */
 594     goacc_attach_host_thread_to_device (ord);
 595   else
 596     {
 597       gomp_mutex_lock (&acc_device_lock);
 598
 599       cached_base_dev = base_dev = resolve_device (d, true);
 600
 601       num_devices = base_dev->get_num_devices_func ();
 602
 603       if (num_devices <= 0 || ord >= num_devices)
 604         acc_dev_num_out_of_range (d, ord, num_devices);
 605
 606       acc_dev = &base_dev[ord];
 607
 608       gomp_mutex_lock (&acc_dev->lock);
 609       if (!acc_dev->is_initialized)
 610         gomp_init_device (acc_dev);
 611       gomp_mutex_unlock (&acc_dev->lock);
 612
 613       gomp_mutex_unlock (&acc_device_lock);
 614
 615       goacc_attach_host_thread_to_device (ord);
 616     }
 617
 618   goacc_device_num = ord;
 619 }
 620
 621 ialias (acc_set_device_num)
 622
 623 /* Compile on_device with optimization, so that the compiler expands
 624    this, rather than generating infinitely recursive code.  */
 625
 626 int __attribute__ ((__optimize__ ("O2")))
 627 acc_on_device (acc_device_t dev)
 628 {
 629   return __builtin_acc_on_device (dev);
 630 }
 631
 632 ialias (acc_on_device)
 633
 634 attribute_hidden void
 635 goacc_runtime_initialize (void)
 636 {
 637   gomp_mutex_init (&acc_device_lock);
 638
 639 #if !(defined HAVE_TLS || defined USE_EMUTLS)
 640   pthread_key_create (&goacc_tls_key, NULL);
 641 #endif
 642
 643   pthread_key_create (&goacc_cleanup_key, goacc_destroy_thread);
 644
 645   cached_base_dev = NULL;
 646
 647   goacc_threads = NULL;
 648   gomp_mutex_init (&goacc_thread_lock);
 649
 650   /* Initialize and register the 'host' device type.  */
 651   goacc_host_init ();
 652 }
 653
 654 /* Compiler helper functions */
 655
 656 attribute_hidden void
 657 goacc_save_and_set_bind (acc_device_t d)
 658 {
 659   struct goacc_thread *thr = goacc_thread ();
 660
 661   assert (!thr->saved_bound_dev);
 662
 663   thr->saved_bound_dev = thr->dev;
 664   thr->dev = dispatchers[d];
 665 }
 666
 667 attribute_hidden void
 668 goacc_restore_bind (void)
 669 {
 670   struct goacc_thread *thr = goacc_thread ();
 671
 672   thr->dev = thr->saved_bound_dev;
 673   thr->saved_bound_dev = NULL;
 674 }
 675
 676 /* This is called from any OpenACC support function that may need to implicitly
 677    initialize the libgomp runtime, either globally or from a new host thread.
 678    On exit "goacc_thread" will return a valid & populated thread block.  */
 679
 680 attribute_hidden void
 681 goacc_lazy_initialize (void)
 682 {
 683   struct goacc_thread *thr = goacc_thread ();
 684
 685   if (thr && thr->dev)
 686     return;
 687
 688   if (!cached_base_dev)
 689     acc_init (acc_device_default);
 690   else
 691     goacc_attach_host_thread_to_device (-1);
 692 }