Intel(R) Threading Building Blocks Doxygen Documentation  version 4.2.3
tbb::internal::custom_scheduler< SchedulerTraits > Class Template Reference

A scheduler with a customized evaluation loop. More...

#include <custom_scheduler.h>

Inheritance diagram for tbb::internal::custom_scheduler< SchedulerTraits >:
Collaboration diagram for tbb::internal::custom_scheduler< SchedulerTraits >:

Public Member Functions

taskreceive_or_steal_task (__TBB_ISOLATION_ARG(__TBB_atomic reference_count &completion_ref_count, isolation_tag isolation)) __TBB_override
 Try getting a task from the mailbox or stealing from another scheduler. More...
 

Static Public Member Functions

static generic_schedulerallocate_scheduler (market &m)
 

Private Types

typedef custom_scheduler< SchedulerTraits > scheduler_type
 

Private Member Functions

 custom_scheduler (market &m)
 
void local_wait_for_all (task &parent, task *child) __TBB_override
 Scheduler loop that dispatches tasks. More...
 
void wait_for_all (task &parent, task *child) __TBB_override
 Entry point from client code to the scheduler loop that dispatches tasks. More...
 
void tally_completion_of_predecessor (task &s, __TBB_ISOLATION_ARG(task *&bypass_slot, isolation_tag isolation))
 Decrements ref_count of a predecessor. More...
 
- Private Member Functions inherited from tbb::internal::generic_scheduler
bool is_task_pool_published () const
 
bool is_local_task_pool_quiescent () const
 
bool is_quiescent_local_task_pool_empty () const
 
bool is_quiescent_local_task_pool_reset () const
 
void attach_mailbox (affinity_id id)
 
void init_stack_info ()
 Sets up the data necessary for the stealing limiting heuristics. More...
 
bool can_steal ()
 Returns true if stealing is allowed. More...
 
void publish_task_pool ()
 Used by workers to enter the task pool. More...
 
void leave_task_pool ()
 Leave the task pool. More...
 
void reset_task_pool_and_leave ()
 Resets head and tail indices to 0, and leaves task pool. More...
 
task ** lock_task_pool (arena_slot *victim_arena_slot) const
 Locks victim's task pool, and returns pointer to it. The pointer can be NULL. More...
 
void unlock_task_pool (arena_slot *victim_arena_slot, task **victim_task_pool) const
 Unlocks victim's task pool. More...
 
void acquire_task_pool () const
 Locks the local task pool. More...
 
void release_task_pool () const
 Unlocks the local task pool. More...
 
taskprepare_for_spawning (task *t)
 Checks if t is affinitized to another thread, and if so, bundles it as proxy. More...
 
void commit_spawned_tasks (size_t new_tail)
 Makes newly spawned tasks visible to thieves. More...
 
void commit_relocated_tasks (size_t new_tail)
 Makes relocated tasks visible to thieves and releases the local task pool. More...
 
taskget_task (__TBB_ISOLATION_EXPR(isolation_tag isolation))
 Get a task from the local pool. More...
 
taskget_task (size_t T)
 Get a task from the local pool at specified location T. More...
 
taskget_mailbox_task (__TBB_ISOLATION_EXPR(isolation_tag isolation))
 Attempt to get a task from the mailbox. More...
 
tasksteal_task (__TBB_ISOLATION_EXPR(isolation_tag isolation))
 Attempts to steal a task from a randomly chosen thread/scheduler. More...
 
tasksteal_task_from (__TBB_ISOLATION_ARG(arena_slot &victim_arena_slot, isolation_tag isolation))
 Steal task from another scheduler's ready pool. More...
 
size_t prepare_task_pool (size_t n)
 Makes sure that the task pool can accommodate at least n more elements. More...
 
bool cleanup_master (bool blocking_terminate)
 Perform necessary cleanup when a master thread stops using TBB. More...
 
void assert_task_pool_valid () const
 
void attach_arena (arena *, size_t index, bool is_master)
 
void nested_arena_entry (arena *, size_t)
 
void nested_arena_exit ()
 
void wait_until_empty ()
 
void spawn (task &first, task *&next) __TBB_override
 For internal use only. More...
 
void spawn_root_and_wait (task &first, task *&next) __TBB_override
 For internal use only. More...
 
void enqueue (task &, void *reserved) __TBB_override
 For internal use only. More...
 
void local_spawn (task *first, task *&next)
 
void local_spawn_root_and_wait (task *first, task *&next)
 
void free_scheduler ()
 Destroy and deallocate this scheduler object. More...
 
taskallocate_task (size_t number_of_bytes, __TBB_CONTEXT_ARG(task *parent, task_group_context *context))
 Allocate task object, either from the heap or a free list. More...
 
template<free_task_hint h>
void free_task (task &t)
 Put task on free list. More...
 
void deallocate_task (task &t)
 Return task object to the memory allocator. More...
 
bool is_worker () const
 True if running on a worker thread, false otherwise. More...
 
bool outermost_level () const
 True if the scheduler is on the outermost dispatch level. More...
 
bool master_outermost_level () const
 True if the scheduler is on the outermost dispatch level in a master thread. More...
 
bool worker_outermost_level () const
 True if the scheduler is on the outermost dispatch level in a worker thread. More...
 
unsigned max_threads_in_arena ()
 Returns the concurrency limit of the current arena. More...
 
void free_nonlocal_small_task (task &t)
 Free a small task t that that was allocated by a different scheduler. More...
 
 generic_scheduler (market &)
 
- Private Member Functions inherited from tbb::internal::scheduler
virtual ~scheduler ()=0
 Pure virtual destructor;. More...
 

Additional Inherited Members

- Static Private Member Functions inherited from tbb::internal::generic_scheduler
static bool is_version_3_task (task &t)
 
static bool is_proxy (const task &t)
 True if t is a task_proxy. More...
 
static generic_schedulercreate_master (arena *a)
 Initialize a scheduler for a master thread. More...
 
static generic_schedulercreate_worker (market &m, size_t index)
 Initialize a scheduler for a worker thread. More...
 
static void cleanup_worker (void *arg, bool worker)
 Perform necessary cleanup when a worker thread finishes. More...
 
static taskplugged_return_list ()
 Special value used to mark my_return_list as not taking any more entries. More...
 
- Private Attributes inherited from tbb::internal::generic_scheduler
uintptr_t my_stealing_threshold
 Position in the call stack specifying its maximal filling when stealing is still allowed. More...
 
marketmy_market
 The market I am in. More...
 
FastRandom my_random
 Random number generator used for picking a random victim from which to steal. More...
 
taskmy_free_list
 Free list of small tasks that can be reused. More...
 
taskmy_dummy_task
 Fake root task created by slave threads. More...
 
long my_ref_count
 Reference count for scheduler. More...
 
bool my_auto_initialized
 True if *this was created by automatic TBB initialization. More...
 
__TBB_atomic intptr_t my_small_task_count
 Number of small tasks that have been allocated by this scheduler. More...
 
taskmy_return_list
 List of small tasks that have been returned to this scheduler by other schedulers. More...
 
- Private Attributes inherited from tbb::internal::intrusive_list_node
intrusive_list_nodemy_prev_node
 
intrusive_list_nodemy_next_node
 
- Private Attributes inherited from tbb::internal::scheduler_state
size_t my_arena_index
 Index of the arena slot the scheduler occupies now, or occupied last time. More...
 
arena_slotmy_arena_slot
 Pointer to the slot in the arena we own at the moment. More...
 
arenamy_arena
 The arena that I own (if master) or am servicing at the moment (if worker) More...
 
taskmy_innermost_running_task
 Innermost task whose task::execute() is running. A dummy task on the outermost level. More...
 
mail_inbox my_inbox
 
affinity_id my_affinity_id
 The mailbox id assigned to this scheduler. More...
 
scheduler_properties my_properties
 
- Static Private Attributes inherited from tbb::internal::generic_scheduler
static const size_t quick_task_size = 256-task_prefix_reservation_size
 If sizeof(task) is <=quick_task_size, it is handled on a free list instead of malloc'd. More...
 
static const size_t null_arena_index = ~size_t(0)
 
static const size_t min_task_pool_size = 64
 

Detailed Description

template<typename SchedulerTraits>
class tbb::internal::custom_scheduler< SchedulerTraits >

A scheduler with a customized evaluation loop.

The customization can use SchedulerTraits to make decisions without needing a run-time check.

Definition at line 56 of file custom_scheduler.h.

Member Typedef Documentation

◆ scheduler_type

template<typename SchedulerTraits >
typedef custom_scheduler<SchedulerTraits> tbb::internal::custom_scheduler< SchedulerTraits >::scheduler_type
private

Definition at line 57 of file custom_scheduler.h.

Constructor & Destructor Documentation

◆ custom_scheduler()

template<typename SchedulerTraits >
tbb::internal::custom_scheduler< SchedulerTraits >::custom_scheduler ( market m)
inlineprivate

Definition at line 59 of file custom_scheduler.h.

Member Function Documentation

◆ allocate_scheduler()

template<typename SchedulerTraits >
static generic_scheduler* tbb::internal::custom_scheduler< SchedulerTraits >::allocate_scheduler ( market m)
inlinestatic

Definition at line 123 of file custom_scheduler.h.

123  {
124  void* p = NFS_Allocate(1, sizeof(scheduler_type), NULL);
125  std::memset(p, 0, sizeof(scheduler_type));
126  scheduler_type* s = new( p ) scheduler_type( m );
127  s->assert_task_pool_valid();
128  ITT_SYNC_CREATE(s, SyncType_Scheduler, SyncObj_TaskPoolSpinning);
129  return s;
130  }
void *__TBB_EXPORTED_FUNC NFS_Allocate(size_t n_element, size_t element_size, void *hint)
Allocate memory on cache/sector line boundary.
#define ITT_SYNC_CREATE(obj, type, name)
Definition: itt_notify.h:123
void const char const char int ITT_FORMAT __itt_group_sync p
void const char const char int ITT_FORMAT __itt_group_sync s
custom_scheduler< SchedulerTraits > scheduler_type

References ITT_SYNC_CREATE, tbb::internal::NFS_Allocate(), p, and s.

Here is the call graph for this function:

◆ local_wait_for_all()

template<typename SchedulerTraits >
void tbb::internal::custom_scheduler< SchedulerTraits >::local_wait_for_all ( task parent,
task child 
)
privatevirtual

Scheduler loop that dispatches tasks.

If child is non-NULL, it is dispatched first. Then, until "parent" has a reference count of 1, other task are dispatched or stolen.

Implements tbb::internal::generic_scheduler.

Definition at line 360 of file custom_scheduler.h.

360  {
361  __TBB_ASSERT( governor::is_set(this), NULL );
362  __TBB_ASSERT( parent.ref_count() >= (child && child->parent() == &parent ? 2 : 1), "ref_count is too small" );
365  // Using parent's refcount in sync_prepare (in the stealing loop below) is
366  // a workaround for TP. We need to name it here to display correctly in Ampl.
367  if( SchedulerTraits::itt_possible )
368  ITT_SYNC_CREATE(&parent.prefix().ref_count, SyncType_Scheduler, SyncObj_TaskStealingLoop);
369 #if __TBB_TASK_GROUP_CONTEXT
370  __TBB_ASSERT( parent.prefix().context, "parent task does not have context" );
371 #endif /* __TBB_TASK_GROUP_CONTEXT */
372  task* t = child;
373  // Constant all_local_work_done is an unreachable refcount value that prevents
374  // early quitting the dispatch loop. It is defined to be in the middle of the range
375  // of negative values representable by the reference_count type.
376  static const reference_count
377  // For normal dispatch loops
378  parents_work_done = 1,
379  // For termination dispatch loops in masters
380  all_local_work_done = (reference_count)3 << (sizeof(reference_count) * 8 - 2);
381  reference_count quit_point;
382 #if __TBB_TASK_PRIORITY
383  __TBB_ASSERT( (uintptr_t)*my_ref_top_priority < (uintptr_t)num_priority_levels, NULL );
384  volatile intptr_t *old_ref_top_priority = my_ref_top_priority;
385  // When entering nested parallelism level market level counter
386  // must be replaced with the one local to this arena.
387  volatile uintptr_t *old_ref_reload_epoch = my_ref_reload_epoch;
388 #endif /* __TBB_TASK_PRIORITY */
389  task* old_innermost_running_task = my_innermost_running_task;
390  scheduler_properties old_properties = my_properties;
391  // Remove outermost property to indicate nested level.
392  __TBB_ASSERT( my_properties.outermost || my_innermost_running_task!=my_dummy_task, "The outermost property should be set out of a dispatch loop" );
394 #if __TBB_TASK_ISOLATION
395  isolation_tag isolation = my_innermost_running_task->prefix().isolation;
396 #endif /* __TBB_TASK_ISOLATION */
397  if( master_outermost_level() ) {
398  // We are in the outermost task dispatch loop of a master thread or a worker which mimics master
399  quit_point = &parent == my_dummy_task ? all_local_work_done : parents_work_done;
400  } else {
401  quit_point = parents_work_done;
402 #if __TBB_TASK_PRIORITY
403  if ( &parent != my_dummy_task ) {
404  // We are in a nested dispatch loop.
405  // Market or arena priority must not prevent child tasks from being
406  // executed so that dynamic priority changes did not cause deadlock.
407  my_ref_top_priority = &parent.prefix().context->my_priority;
408  my_ref_reload_epoch = &my_arena->my_reload_epoch;
409  if(my_ref_reload_epoch != old_ref_reload_epoch)
410  my_local_reload_epoch = *my_ref_reload_epoch-1;
411  }
412 #endif /* __TBB_TASK_PRIORITY */
413  }
414 
415  context_guard_helper</*report_tasks=*/SchedulerTraits::itt_possible> context_guard;
416  if ( t ) {
417  context_guard.set_ctx( __TBB_CONTEXT_ARG1(t->prefix().context) );
418 #if __TBB_TASK_ISOLATION
419  if ( isolation != no_isolation ) {
420  __TBB_ASSERT( t->prefix().isolation == no_isolation, NULL );
421  // Propagate the isolation to the task executed without spawn.
422  t->prefix().isolation = isolation;
423  }
424 #endif /* __TBB_TASK_ISOLATION */
425  }
426 #if TBB_USE_EXCEPTIONS
427  // Infinite safeguard EH loop
428  for (;;) {
429  try {
430 #endif /* TBB_USE_EXCEPTIONS */
431  // Outer loop receives tasks from global environment (via mailbox, FIFO queue(s),
432  // and by stealing from other threads' task pools).
433  // All exit points from the dispatch loop are located in its immediate scope.
434  for(;;) {
435  // Middle loop retrieves tasks from the local task pool.
436  for(;;) {
437  // Inner loop evaluates tasks coming from nesting loops and those returned
438  // by just executed tasks (bypassing spawn or enqueue calls).
439  while(t) {
440  __TBB_ASSERT( my_inbox.is_idle_state(false), NULL );
441  __TBB_ASSERT(!is_proxy(*t),"unexpected proxy");
442  __TBB_ASSERT( t->prefix().owner, NULL );
443 #if __TBB_TASK_ISOLATION
444  __TBB_ASSERT( isolation == no_isolation || isolation == t->prefix().isolation,
445  "A task from another isolated region is going to be executed" );
446 #endif /* __TBB_TASK_ISOLATION */
448 #if __TBB_TASK_GROUP_CONTEXT && TBB_USE_ASSERT
449  assert_context_valid(t->prefix().context);
450  if ( !t->prefix().context->my_cancellation_requested )
451 #endif
452  // TODO: make the assert stronger by prohibiting allocated state.
453  __TBB_ASSERT( 1L<<t->state() & (1L<<task::allocated|1L<<task::ready|1L<<task::reexecute), NULL );
455 #if __TBB_PREVIEW_CRITICAL_TASKS
456  // TODO: check performance and optimize if needed for added conditions on the
457  // hot-path.
458  if( !internal::is_critical(*t) ) {
459  if( task* critical_task = get_critical_task( __TBB_ISOLATION_EXPR(isolation) ) ) {
460  __TBB_ASSERT( internal::is_critical(*critical_task),
461  "Received task must be critical one" );
462  ITT_NOTIFY(sync_acquired, &my_arena->my_critical_task_stream);
463  t->prefix().state = task::allocated;
464  my_innermost_running_task = t; // required during spawn to propagate isolation
465  local_spawn(t, t->prefix().next);
466  t = critical_task;
467  } else {
468 #endif /* __TBB_PREVIEW_CRITICAL_TASKS */
469 #if __TBB_TASK_PRIORITY
470  intptr_t p = priority(*t);
471  if ( p != *my_ref_top_priority
472  && (t->prefix().extra_state & es_task_enqueued) == 0 ) {
473  assert_priority_valid(p);
474  if ( p != my_arena->my_top_priority ) {
475  my_market->update_arena_priority( *my_arena, p );
476  }
477  if ( p < effective_reference_priority() ) {
478  if ( !my_offloaded_tasks ) {
479  my_offloaded_task_list_tail_link = &t->prefix().next_offloaded;
480  // Erase possible reference to the owner scheduler
481  // (next_offloaded is a union member)
482  *my_offloaded_task_list_tail_link = NULL;
483  }
484  offload_task( *t, p );
485  if ( is_task_pool_published() ) {
486  t = winnow_task_pool( __TBB_ISOLATION_EXPR( isolation ) );
487  if ( t )
488  continue;
489  } else {
490  // Mark arena as full to unlock arena priority level adjustment
491  // by arena::is_out_of_work(), and ensure worker's presence.
493  }
494  goto stealing_ground;
495  }
496  }
497 #endif /* __TBB_TASK_PRIORITY */
498 #if __TBB_PREVIEW_CRITICAL_TASKS
499  }
500  } // if is not critical
501 #endif
502  task* t_next = NULL;
504  t->prefix().owner = this;
505  t->prefix().state = task::executing;
506 #if __TBB_TASK_GROUP_CONTEXT
507  if ( !t->prefix().context->my_cancellation_requested )
508 #endif
509  {
510  GATHER_STATISTIC( ++my_counters.tasks_executed );
511  GATHER_STATISTIC( my_counters.avg_arena_concurrency += my_arena->num_workers_active() );
512  GATHER_STATISTIC( my_counters.avg_assigned_workers += my_arena->my_num_workers_allotted );
513 #if __TBB_TASK_PRIORITY
514  GATHER_STATISTIC( my_counters.avg_arena_prio += p );
515  GATHER_STATISTIC( my_counters.avg_market_prio += my_market->my_global_top_priority );
516 #endif /* __TBB_TASK_PRIORITY */
517  ITT_STACK(SchedulerTraits::itt_possible, callee_enter, t->prefix().context->itt_caller);
518 #if __TBB_PREVIEW_CRITICAL_TASKS
519  internal::critical_task_count_guard tc_guard(my_properties, *t);
520 #endif
521  t_next = t->execute();
522  ITT_STACK(SchedulerTraits::itt_possible, callee_leave, t->prefix().context->itt_caller);
523  if (t_next) {
524  __TBB_ASSERT( t_next->state()==task::allocated,
525  "if task::execute() returns task, it must be marked as allocated" );
526  reset_extra_state(t_next);
527  __TBB_ISOLATION_EXPR( t_next->prefix().isolation = t->prefix().isolation );
528 #if TBB_USE_ASSERT
529  affinity_id next_affinity=t_next->prefix().affinity;
530  if (next_affinity != 0 && next_affinity != my_affinity_id)
531  GATHER_STATISTIC( ++my_counters.affinity_ignored );
532 #endif
533  } // if there is bypassed task
534  }
536  switch( t->state() ) {
537  case task::executing: {
538  task* s = t->parent();
540  __TBB_ASSERT( t->prefix().ref_count==0, "Task still has children after it has been executed" );
541  t->~task();
542  if( s )
543  tally_completion_of_predecessor( *s, __TBB_ISOLATION_ARG( t_next, t->prefix().isolation ) );
544  free_task<no_hint>( *t );
547  break;
548  }
549 
550  case task::recycle: // set by recycle_as_safe_continuation()
551  t->prefix().state = task::allocated;
552 #if __TBB_RECYCLE_TO_ENQUEUE
554  case task::to_enqueue: // set by recycle_to_enqueue()
555 #endif
556  __TBB_ASSERT( t_next != t, "a task returned from method execute() can not be recycled in another way" );
558  // for safe continuation, need atomically decrement ref_count;
559  tally_completion_of_predecessor(*t, __TBB_ISOLATION_ARG( t_next, t->prefix().isolation ) );
561  break;
562 
563  case task::reexecute: // set by recycle_to_reexecute()
564  __TBB_ASSERT( t_next, "reexecution requires that method execute() return another task" );
565  __TBB_ASSERT( t_next != t, "a task returned from method execute() can not be recycled in another way" );
566  t->prefix().state = task::allocated;
568  local_spawn( t, t->prefix().next );
570  break;
571  case task::allocated:
573  break;
574 #if TBB_USE_ASSERT
575  case task::ready:
576  __TBB_ASSERT( false, "task is in READY state upon return from method execute()" );
577  break;
578  default:
579  __TBB_ASSERT( false, "illegal state" );
580 #else
581  default: // just to shut up some compilation warnings
582  break;
583 #endif /* TBB_USE_ASSERT */
584  }
585  GATHER_STATISTIC( t_next ? ++my_counters.spawns_bypassed : 0 );
586  t = t_next;
587  } // end of scheduler bypass loop
588 
590  if ( parent.prefix().ref_count == quit_point ) {
591  __TBB_ASSERT( quit_point != all_local_work_done, NULL );
592  __TBB_control_consistency_helper(); // on ref_count
593  ITT_NOTIFY(sync_acquired, &parent.prefix().ref_count);
594  goto done;
595  }
596  if ( is_task_pool_published() ) {
597  t = get_task( __TBB_ISOLATION_EXPR( isolation ) );
598  } else {
600  break;
601  }
603 
604  if ( !t ) break;
605 
606  context_guard.set_ctx( __TBB_CONTEXT_ARG1(t->prefix().context) );
607  }; // end of local task pool retrieval loop
608 
609 #if __TBB_TASK_PRIORITY
610 stealing_ground:
611 #endif /* __TBB_TASK_PRIORITY */
612 #if __TBB_HOARD_NONLOCAL_TASKS
613  // before stealing, previously stolen task objects are returned
614  for (; my_nonlocal_free_list; my_nonlocal_free_list = t ) {
615  t = my_nonlocal_free_list->prefix().next;
616  free_nonlocal_small_task( *my_nonlocal_free_list );
617  }
618 #endif
619  if ( quit_point == all_local_work_done ) {
622  my_innermost_running_task = old_innermost_running_task;
623  my_properties = old_properties;
624 #if __TBB_TASK_PRIORITY
625  my_ref_top_priority = old_ref_top_priority;
626  if(my_ref_reload_epoch != old_ref_reload_epoch)
627  my_local_reload_epoch = *old_ref_reload_epoch-1;
628  my_ref_reload_epoch = old_ref_reload_epoch;
629 #endif /* __TBB_TASK_PRIORITY */
630  return;
631  }
632 
633  t = receive_or_steal_task( __TBB_ISOLATION_ARG( parent.prefix().ref_count, isolation ) );
634  if ( !t )
635  goto done;
636  // The user can capture another the FPU settings to the context so the
637  // cached data in the helper can be out-of-date and we cannot do fast
638  // check.
639  context_guard.set_ctx( __TBB_CONTEXT_ARG1(t->prefix().context) );
640  } // end of infinite stealing loop
641 #if TBB_USE_EXCEPTIONS
642  __TBB_ASSERT( false, "Must never get here" );
643  } // end of try-block
644  TbbCatchAll( t->prefix().context );
645  // Complete post-processing ...
646  if( t->state() == task::recycle
647 #if __TBB_RECYCLE_TO_ENQUEUE
648  // TODO: the enqueue semantics gets lost below, consider reimplementing
649  || t->state() == task::to_enqueue
650 #endif
651  ) {
652  // ... for recycled tasks to atomically decrement ref_count
653  t->prefix().state = task::allocated;
654  if( SchedulerTraits::itt_possible )
655  ITT_NOTIFY(sync_releasing, &t->prefix().ref_count);
656  if( __TBB_FetchAndDecrementWrelease(&t->prefix().ref_count)==1 ) {
657  if( SchedulerTraits::itt_possible )
658  ITT_NOTIFY(sync_acquired, &t->prefix().ref_count);
659  }else{
660  t = NULL;
661  }
662  }
663  } // end of infinite EH loop
664  __TBB_ASSERT( false, "Must never get here too" );
665 #endif /* TBB_USE_EXCEPTIONS */
666 done:
667  my_innermost_running_task = old_innermost_running_task;
668  my_properties = old_properties;
669 #if __TBB_TASK_PRIORITY
670  my_ref_top_priority = old_ref_top_priority;
671  if(my_ref_reload_epoch != old_ref_reload_epoch)
672  my_local_reload_epoch = *old_ref_reload_epoch-1;
673  my_ref_reload_epoch = old_ref_reload_epoch;
674 #endif /* __TBB_TASK_PRIORITY */
675  if ( !ConcurrentWaitsEnabled(parent) ) {
676  if ( parent.prefix().ref_count != parents_work_done ) {
677  // This is a worker that was revoked by the market.
679  "Worker thread exits nested dispatch loop prematurely" );
680  return;
681  }
682  parent.prefix().ref_count = 0;
683  }
684 #if TBB_USE_ASSERT
685  parent.prefix().extra_state &= ~es_ref_count_active;
686 #endif /* TBB_USE_ASSERT */
687 #if __TBB_TASK_GROUP_CONTEXT
688  __TBB_ASSERT(parent.prefix().context && default_context(), NULL);
689  task_group_context* parent_ctx = parent.prefix().context;
690  if ( parent_ctx->my_cancellation_requested ) {
691  task_group_context::exception_container_type *pe = parent_ctx->my_exception;
692  if ( master_outermost_level() && parent_ctx == default_context() ) {
693  // We are in the outermost task dispatch loop of a master thread, and
694  // the whole task tree has been collapsed. So we may clear cancellation data.
695  parent_ctx->my_cancellation_requested = 0;
696  // TODO: Add assertion that master's dummy task context does not have children
697  parent_ctx->my_state &= ~(uintptr_t)task_group_context::may_have_children;
698  }
699  if ( pe ) {
700  // On Windows, FPU control settings changed in the helper destructor are not visible
701  // outside a catch block. So restore the default settings manually before rethrowing
702  // the exception.
703  context_guard.restore_default();
704  TbbRethrowException( pe );
705  }
706  }
707  __TBB_ASSERT(!is_worker() || !CancellationInfoPresent(*my_dummy_task),
708  "Worker's dummy task context modified");
709  __TBB_ASSERT(!master_outermost_level() || !CancellationInfoPresent(*my_dummy_task),
710  "Unexpected exception or cancellation data in the master's dummy task");
711 #endif /* __TBB_TASK_GROUP_CONTEXT */
713 }
#define ITT_STACK(precond, name, obj)
Definition: itt_notify.h:126
unsigned my_num_workers_allotted
The number of workers that have been marked out by the resource manager to service the arena.
Definition: arena.h:55
unsigned short affinity_id
An id as used for specifying affinity.
Definition: task.h:124
Set if ref_count might be changed by another thread. Used for debugging.
#define __TBB_FetchAndDecrementWrelease(P)
Definition: tbb_machine.h:315
#define __TBB_ASSERT(predicate, comment)
No-op version of __TBB_ASSERT.
Definition: tbb_stddef.h:169
const isolation_tag no_isolation
Definition: task.h:129
task object is freshly allocated or recycled.
Definition: task.h:620
#define __TBB_ISOLATION_EXPR(isolation)
#define ITT_SYNC_CREATE(obj, type, name)
Definition: itt_notify.h:123
bool is_quiescent_local_task_pool_reset() const
Definition: scheduler.h:566
void reset_extra_state(task *t)
bool is_worker() const
True if running on a worker thread, false otherwise.
Definition: scheduler.h:595
task * receive_or_steal_task(__TBB_ISOLATION_ARG(__TBB_atomic reference_count &completion_ref_count, isolation_tag isolation)) __TBB_override
Try getting a task from the mailbox or stealing from another scheduler.
task * my_innermost_running_task
Innermost task whose task::execute() is running. A dummy task on the outermost level.
Definition: scheduler.h:81
intptr_t isolation_tag
A tag for task isolation.
Definition: task.h:128
task is running, and will be destroyed after method execute() completes.
Definition: task.h:614
task * get_task(__TBB_ISOLATION_EXPR(isolation_tag isolation))
Get a task from the local pool.
Definition: scheduler.cpp:978
market * my_market
The market I am in.
Definition: scheduler.h:159
void const char const char int ITT_FORMAT __itt_group_sync p
bool is_critical(task &t)
Definition: task.h:953
#define __TBB_ISOLATION_ARG(arg1, isolation)
void const char const char int ITT_FORMAT __itt_group_sync x void const char ITT_FORMAT __itt_group_sync s void ITT_FORMAT __itt_group_sync p void ITT_FORMAT p void ITT_FORMAT p no args __itt_suppress_mode_t unsigned int void size_t ITT_FORMAT d void ITT_FORMAT p void ITT_FORMAT p __itt_model_site __itt_model_site_instance ITT_FORMAT p __itt_model_task * task
static const intptr_t num_priority_levels
void local_spawn(task *first, task *&next)
Definition: scheduler.cpp:618
#define GATHER_STATISTIC(x)
static bool is_proxy(const task &t)
True if t is a task_proxy.
Definition: scheduler.h:273
bool master_outermost_level() const
True if the scheduler is on the outermost dispatch level in a master thread.
Definition: scheduler.h:575
task to be recycled as continuation
Definition: task.h:624
void const char const char int ITT_FORMAT __itt_group_sync x void const char ITT_FORMAT __itt_group_sync s void ITT_FORMAT __itt_group_sync p void ITT_FORMAT p void ITT_FORMAT p no args __itt_suppress_mode_t unsigned int void size_t ITT_FORMAT d void ITT_FORMAT p void ITT_FORMAT p __itt_model_site __itt_model_site_instance ITT_FORMAT p __itt_model_task __itt_model_task_instance ITT_FORMAT p void ITT_FORMAT p void ITT_FORMAT p void size_t ITT_FORMAT d void ITT_FORMAT p const wchar_t ITT_FORMAT s const char ITT_FORMAT s const char ITT_FORMAT s const char ITT_FORMAT s no args void ITT_FORMAT p size_t ITT_FORMAT d no args const wchar_t const wchar_t ITT_FORMAT s __itt_heap_function void size_t int ITT_FORMAT d __itt_heap_function void ITT_FORMAT p __itt_heap_function void void size_t int ITT_FORMAT d no args no args unsigned int ITT_FORMAT u const __itt_domain __itt_id ITT_FORMAT lu const __itt_domain __itt_id __itt_id parent
void const char const char int ITT_FORMAT __itt_group_sync x void const char ITT_FORMAT __itt_group_sync s void ITT_FORMAT __itt_group_sync p void ITT_FORMAT p sync_releasing
internal::tbb_exception_ptr exception_container_type
Definition: task.h:344
task is in ready pool, or is going to be put there, or was just taken off.
Definition: task.h:618
bool outermost
Indicates that a scheduler is on outermost level.
Definition: scheduler.h:57
void poison_pointer(T *__TBB_atomic &)
Definition: tbb_stddef.h:309
scheduler_properties my_properties
Definition: scheduler.h:95
#define ITT_NOTIFY(name, obj)
Definition: itt_notify.h:120
void const char const char int ITT_FORMAT __itt_group_sync s
#define __TBB_CONTEXT_ARG1(context)
void tally_completion_of_predecessor(task &s, __TBB_ISOLATION_ARG(task *&bypass_slot, isolation_tag isolation))
Decrements ref_count of a predecessor.
task * my_dummy_task
Fake root task created by slave threads.
Definition: scheduler.h:173
static bool is_set(generic_scheduler *s)
Used to check validity of the local scheduler TLS contents.
Definition: governor.cpp:124
intptr_t reference_count
A reference count.
Definition: task.h:121
internal::task_prefix & prefix(internal::version_tag *=NULL) const
Get reference to corresponding task_prefix.
Definition: task.h:941
bool is_idle_state(bool value) const
Indicate whether thread that reads this mailbox is idle.
Definition: mailbox.h:222
void assert_task_valid(const task *)
bool ConcurrentWaitsEnabled(task &t)
#define __TBB_control_consistency_helper()
Definition: gcc_generic.h:64
unsigned num_workers_active()
The number of workers active in the arena.
Definition: arena.h:237
void advertise_new_work()
If necessary, raise a flag that there is new job in arena.
Definition: arena.h:393
#define __TBB_fallthrough
Definition: tbb_stddef.h:254
task to be rescheduled.
Definition: task.h:616
affinity_id my_affinity_id
The mailbox id assigned to this scheduler.
Definition: scheduler.h:93
bool worker_outermost_level() const
True if the scheduler is on the outermost dispatch level in a worker thread.
Definition: scheduler.h:579
void free_nonlocal_small_task(task &t)
Free a small task t that that was allocated by a different scheduler.
Definition: scheduler.cpp:379
arena * my_arena
The arena that I own (if master) or am servicing at the moment (if worker)
Definition: scheduler.h:78

References __TBB_ASSERT, __TBB_CONTEXT_ARG1, __TBB_control_consistency_helper, __TBB_fallthrough, __TBB_FetchAndDecrementWrelease, __TBB_ISOLATION_ARG, __TBB_ISOLATION_EXPR, tbb::task::allocated, tbb::internal::assert_task_valid(), tbb::internal::ConcurrentWaitsEnabled(), tbb::internal::es_ref_count_active, tbb::internal::es_task_enqueued, tbb::task::execute(), tbb::task::executing, GATHER_STATISTIC, tbb::internal::is_critical(), tbb::internal::governor::is_set(), ITT_NOTIFY, ITT_STACK, ITT_SYNC_CREATE, tbb::task_group_context::may_have_children, tbb::internal::no_isolation, tbb::internal::num_priority_levels, p, parent, tbb::task::parent(), tbb::internal::poison_pointer(), tbb::task::prefix(), tbb::task::ready, tbb::task::recycle, tbb::task::reexecute, tbb::internal::reset_extra_state(), s, tbb::internal::context_guard_helper< T >::set_ctx(), tbb::task::state(), sync_releasing, and tbb::internal::arena::wakeup.

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◆ receive_or_steal_task()

template<typename SchedulerTraits >
task * tbb::internal::custom_scheduler< SchedulerTraits >::receive_or_steal_task ( __TBB_ISOLATION_ARG(__TBB_atomic reference_count &completion_ref_count, isolation_tag isolation)  )
virtual

Try getting a task from the mailbox or stealing from another scheduler.

Returns the stolen task or NULL if all attempts fail.

Implements tbb::internal::generic_scheduler.

Definition at line 142 of file custom_scheduler.h.

142  {
143  task* t = NULL;
144  bool outermost_worker_level = worker_outermost_level();
145  bool outermost_dispatch_level = outermost_worker_level || master_outermost_level();
146  bool can_steal_here = can_steal();
147  my_inbox.set_is_idle( true );
148 #if __TBB_HOARD_NONLOCAL_TASKS
149  __TBB_ASSERT(!my_nonlocal_free_list, NULL);
150 #endif
151 #if __TBB_TASK_PRIORITY
152  if ( outermost_dispatch_level ) {
153  if ( intptr_t skipped_priority = my_arena->my_skipped_fifo_priority ) {
154  // This thread can dequeue FIFO tasks, and some priority levels of
155  // FIFO tasks have been bypassed (to prevent deadlock caused by
156  // dynamic priority changes in nested task group hierarchy).
157  if ( my_arena->my_skipped_fifo_priority.compare_and_swap(0, skipped_priority) == skipped_priority
158  && skipped_priority > my_arena->my_top_priority )
159  {
160  my_market->update_arena_priority( *my_arena, skipped_priority );
161  }
162  }
163  }
164 #endif /* !__TBB_TASK_PRIORITY */
165  // TODO: Try to find a place to reset my_limit (under market's lock)
166  // The number of slots potentially used in the arena. Updated once in a while, as my_limit changes rarely.
167  size_t n = my_arena->my_limit-1;
168  int yield_count = 0;
169  // The state "failure_count==-1" is used only when itt_possible is true,
170  // and denotes that a sync_prepare has not yet been issued.
171  for( int failure_count = -static_cast<int>(SchedulerTraits::itt_possible);; ++failure_count) {
172  __TBB_ASSERT( my_arena->my_limit > 0, NULL );
173  __TBB_ASSERT( my_arena_index <= n, NULL );
174  if( completion_ref_count==1 ) {
175  if( SchedulerTraits::itt_possible ) {
176  if( failure_count!=-1 ) {
177  ITT_NOTIFY(sync_prepare, &completion_ref_count);
178  // Notify Intel(R) Thread Profiler that thread has stopped spinning.
179  ITT_NOTIFY(sync_acquired, this);
180  }
181  ITT_NOTIFY(sync_acquired, &completion_ref_count);
182  }
183  __TBB_ASSERT( !t, NULL );
184  // A worker thread in its outermost dispatch loop (i.e. its execution stack is empty) should
185  // exit it either when there is no more work in the current arena, or when revoked by the market.
186  __TBB_ASSERT( !outermost_worker_level, NULL );
187  __TBB_control_consistency_helper(); // on ref_count
188  break; // exit stealing loop and return;
189  }
190  // Check if the resource manager requires our arena to relinquish some threads
191  if ( outermost_worker_level && (my_arena->my_num_workers_allotted < my_arena->num_workers_active()
192 #if __TBB_ENQUEUE_ENFORCED_CONCURRENCY
193  || my_arena->recall_by_mandatory_request()
194 #endif
195  ) ) {
196  if( SchedulerTraits::itt_possible && failure_count != -1 )
197  ITT_NOTIFY(sync_cancel, this);
198  return NULL;
199  }
200 #if __TBB_TASK_PRIORITY
201  const int p = int(my_arena->my_top_priority);
202 #else /* !__TBB_TASK_PRIORITY */
203  static const int p = 0;
204 #endif
205  // Check if there are tasks mailed to this thread via task-to-thread affinity mechanism.
207  if ( n && !my_inbox.empty() ) {
208  t = get_mailbox_task( __TBB_ISOLATION_EXPR( isolation ) );
209 #if __TBB_TASK_ISOLATION
210  // There is a race with a thread adding a new task (possibly with suitable isolation)
211  // to our mailbox, so the below conditions might result in a false positive.
212  // Then set_is_idle(false) allows that task to be stolen; it's OK.
213  if ( isolation != no_isolation && !t && !my_inbox.empty()
214  && my_inbox.is_idle_state( true ) ) {
215  // We have proxy tasks in our mailbox but the isolation blocks their execution.
216  // So publish the proxy tasks in mailbox to be available for stealing from owner's task pool.
217  my_inbox.set_is_idle( false );
218  }
219 #endif /* __TBB_TASK_ISOLATION */
220  }
221  if ( t ) {
222  GATHER_STATISTIC( ++my_counters.mails_received );
223  }
224  // Check if there are tasks in starvation-resistant stream.
225  // Only allowed at the outermost dispatch level without isolation.
226  else if (__TBB_ISOLATION_EXPR(isolation == no_isolation &&) outermost_dispatch_level &&
228 #if __TBB_PREVIEW_CRITICAL_TASKS && __TBB_CPF_BUILD
229  t = my_arena->my_task_stream.pop( p, subsequent_lane_selector(my_arena_slot->hint_for_pop) )
230 #else
232 #endif
233  ) ) {
234  ITT_NOTIFY(sync_acquired, &my_arena->my_task_stream);
235  // just proceed with the obtained task
236  }
237 #if __TBB_TASK_PRIORITY
238  // Check if any earlier offloaded non-top priority tasks become returned to the top level
239  else if ( my_offloaded_tasks && (t = reload_tasks( __TBB_ISOLATION_EXPR( isolation ) )) ) {
240  __TBB_ASSERT( !is_proxy(*t), "The proxy task cannot be offloaded" );
241  // just proceed with the obtained task
242  }
243 #endif /* __TBB_TASK_PRIORITY */
244  else if ( can_steal_here && n && (t = steal_task( __TBB_ISOLATION_EXPR(isolation) )) ) {
245  // just proceed with the obtained task
246  }
247 #if __TBB_PREVIEW_CRITICAL_TASKS
248  else if( (t = get_critical_task( __TBB_ISOLATION_EXPR(isolation) )) ) {
249  __TBB_ASSERT( internal::is_critical(*t), "Received task must be critical one" );
250  ITT_NOTIFY(sync_acquired, &my_arena->my_critical_task_stream);
251  // just proceed with the obtained task
252  }
253 #endif // __TBB_PREVIEW_CRITICAL_TASKS
254  else
255  goto fail;
256  // A task was successfully obtained somewhere
257  __TBB_ASSERT(t,NULL);
258 #if __TBB_ARENA_OBSERVER
259  my_arena->my_observers.notify_entry_observers( my_last_local_observer, is_worker() );
260 #endif
261 #if __TBB_SCHEDULER_OBSERVER
262  the_global_observer_list.notify_entry_observers( my_last_global_observer, is_worker() );
263 #endif /* __TBB_SCHEDULER_OBSERVER */
264  if ( SchedulerTraits::itt_possible && failure_count != -1 ) {
265  // FIXME - might be victim, or might be selected from a mailbox
266  // Notify Intel(R) Thread Profiler that thread has stopped spinning.
267  ITT_NOTIFY(sync_acquired, this);
268  }
269  break; // exit stealing loop and return
270 fail:
271  GATHER_STATISTIC( ++my_counters.steals_failed );
272  if( SchedulerTraits::itt_possible && failure_count==-1 ) {
273  // The first attempt to steal work failed, so notify Intel(R) Thread Profiler that
274  // the thread has started spinning. Ideally, we would do this notification
275  // *before* the first failed attempt to steal, but at that point we do not
276  // know that the steal will fail.
277  ITT_NOTIFY(sync_prepare, this);
278  failure_count = 0;
279  }
280  // Pause, even if we are going to yield, because the yield might return immediately.
281  prolonged_pause();
282  const int failure_threshold = 2*int(n+1);
283  if( failure_count>=failure_threshold ) {
284 #if __TBB_YIELD2P
285  failure_count = 0;
286 #else
287  failure_count = failure_threshold;
288 #endif
289  __TBB_Yield();
290 #if __TBB_TASK_PRIORITY
291  // Check if there are tasks abandoned by other workers
292  if ( my_arena->my_orphaned_tasks ) {
293  // Epoch must be advanced before seizing the list pointer
294  ++my_arena->my_abandonment_epoch;
295  task* orphans = (task*)__TBB_FetchAndStoreW( &my_arena->my_orphaned_tasks, 0 );
296  if ( orphans ) {
297  task** link = NULL;
298  // Get local counter out of the way (we've just brought in external tasks)
299  my_local_reload_epoch--;
300  t = reload_tasks( orphans, link, __TBB_ISOLATION_ARG( effective_reference_priority(), isolation ) );
301  if ( orphans ) {
302  *link = my_offloaded_tasks;
303  if ( !my_offloaded_tasks )
304  my_offloaded_task_list_tail_link = link;
305  my_offloaded_tasks = orphans;
306  }
307  __TBB_ASSERT( !my_offloaded_tasks == !my_offloaded_task_list_tail_link, NULL );
308  if ( t ) {
309  if( SchedulerTraits::itt_possible )
310  ITT_NOTIFY(sync_cancel, this);
311  __TBB_ASSERT( !is_proxy(*t), "The proxy task cannot be offloaded" );
312  break; // exit stealing loop and return
313  }
314  }
315  }
316 #endif /* __TBB_TASK_PRIORITY */
317  const int yield_threshold = 100;
318  if( yield_count++ >= yield_threshold ) {
319  // When a worker thread has nothing to do, return it to RML.
320  // For purposes of affinity support, the thread is considered idle while in RML.
321 #if __TBB_TASK_PRIORITY
322  if( outermost_worker_level || my_arena->my_top_priority > my_arena->my_bottom_priority ) {
323  if ( my_arena->is_out_of_work() && outermost_worker_level ) {
324 #else /* !__TBB_TASK_PRIORITY */
325  if ( outermost_worker_level && my_arena->is_out_of_work() ) {
326 #endif /* !__TBB_TASK_PRIORITY */
327  if( SchedulerTraits::itt_possible )
328  ITT_NOTIFY(sync_cancel, this);
329  return NULL;
330  }
331 #if __TBB_TASK_PRIORITY
332  }
333  if ( my_offloaded_tasks ) {
334  // Safeguard against any sloppiness in managing reload epoch
335  // counter (e.g. on the hot path because of performance reasons).
336  my_local_reload_epoch--;
337  // Break the deadlock caused by a higher priority dispatch loop
338  // stealing and offloading a lower priority task. Priority check
339  // at the stealing moment cannot completely preclude such cases
340  // because priorities can changes dynamically.
341  if ( !outermost_worker_level && *my_ref_top_priority > my_arena->my_top_priority ) {
342  GATHER_STATISTIC( ++my_counters.prio_ref_fixups );
343  my_ref_top_priority = &my_arena->my_top_priority;
344  // it's expected that only outermost workers can use global reload epoch
345  __TBB_ASSERT(my_ref_reload_epoch == &my_arena->my_reload_epoch, NULL);
346  }
347  }
348 #endif /* __TBB_TASK_PRIORITY */
349  } // end of arena snapshot branch
350  // If several attempts did not find work, re-read the arena limit.
351  n = my_arena->my_limit-1;
352  } // end of yielding branch
353  } // end of nonlocal task retrieval loop
354  if ( my_inbox.is_idle_state( true ) )
355  my_inbox.set_is_idle( false );
356  return t;
357 }
bool can_steal()
Returns true if stealing is allowed.
Definition: scheduler.h:195
unsigned my_num_workers_allotted
The number of workers that have been marked out by the resource manager to service the arena.
Definition: arena.h:55
task * steal_task(__TBB_ISOLATION_EXPR(isolation_tag isolation))
Attempts to steal a task from a randomly chosen thread/scheduler.
Definition: scheduler.cpp:1075
bool empty()
Return true if mailbox is empty.
Definition: mailbox.h:210
#define __TBB_ASSERT(predicate, comment)
No-op version of __TBB_ASSERT.
Definition: tbb_stddef.h:169
const isolation_tag no_isolation
Definition: task.h:129
#define __TBB_ISOLATION_EXPR(isolation)
bool is_worker() const
True if running on a worker thread, false otherwise.
Definition: scheduler.h:595
#define __TBB_Yield()
Definition: ibm_aix51.h:48
market * my_market
The market I am in.
Definition: scheduler.h:159
void const char const char int ITT_FORMAT __itt_group_sync p
task * get_mailbox_task(__TBB_ISOLATION_EXPR(isolation_tag isolation))
Attempt to get a task from the mailbox.
Definition: scheduler.cpp:1200
size_t my_arena_index
Index of the arena slot the scheduler occupies now, or occupied last time.
Definition: scheduler.h:72
bool is_critical(task &t)
Definition: task.h:953
arena_slot * my_arena_slot
Pointer to the slot in the arena we own at the moment.
Definition: scheduler.h:75
#define __TBB_ISOLATION_ARG(arg1, isolation)
bool empty(int level)
Checks existence of a task.
Definition: task_stream.h:142
bool is_out_of_work()
Check if there is job anywhere in arena.
Definition: arena.cpp:407
void const char const char int ITT_FORMAT __itt_group_sync x void const char ITT_FORMAT __itt_group_sync s void ITT_FORMAT __itt_group_sync p void ITT_FORMAT p void ITT_FORMAT p no args __itt_suppress_mode_t unsigned int void size_t ITT_FORMAT d void ITT_FORMAT p void ITT_FORMAT p __itt_model_site __itt_model_site_instance ITT_FORMAT p __itt_model_task * task
void const char const char int ITT_FORMAT __itt_group_sync x void const char ITT_FORMAT __itt_group_sync s void ITT_FORMAT __itt_group_sync p sync_cancel
#define GATHER_STATISTIC(x)
static bool is_proxy(const task &t)
True if t is a task_proxy.
Definition: scheduler.h:273
bool master_outermost_level() const
True if the scheduler is on the outermost dispatch level in a master thread.
Definition: scheduler.h:575
task * pop(int level, unsigned &last_used_lane)
Try finding and popping a task.
Definition: task_stream.h:120
atomic< unsigned > my_limit
The maximal number of currently busy slots.
Definition: arena.h:69
#define ITT_NOTIFY(name, obj)
Definition: itt_notify.h:120
void const char const char int ITT_FORMAT __itt_group_sync x void const char ITT_FORMAT __itt_group_sync s void ITT_FORMAT __itt_group_sync p void ITT_FORMAT p void ITT_FORMAT p no args __itt_suppress_mode_t unsigned int void size_t ITT_FORMAT d void ITT_FORMAT p void ITT_FORMAT p __itt_model_site __itt_model_site_instance ITT_FORMAT p __itt_model_task __itt_model_task_instance ITT_FORMAT p void ITT_FORMAT p void ITT_FORMAT p void size_t ITT_FORMAT d void ITT_FORMAT p const wchar_t ITT_FORMAT s const char ITT_FORMAT s const char ITT_FORMAT s const char ITT_FORMAT s no args void ITT_FORMAT p size_t ITT_FORMAT d no args const wchar_t const wchar_t ITT_FORMAT s __itt_heap_function void size_t int ITT_FORMAT d __itt_heap_function void ITT_FORMAT p __itt_heap_function void void size_t int ITT_FORMAT d no args no args unsigned int ITT_FORMAT u const __itt_domain __itt_id ITT_FORMAT lu const __itt_domain __itt_id __itt_id __itt_string_handle ITT_FORMAT p const __itt_domain __itt_id ITT_FORMAT p const __itt_domain __itt_id __itt_timestamp __itt_timestamp ITT_FORMAT lu const __itt_domain __itt_id __itt_id __itt_string_handle ITT_FORMAT p const __itt_domain ITT_FORMAT p const __itt_domain __itt_string_handle unsigned long long ITT_FORMAT lu const __itt_domain __itt_id __itt_string_handle __itt_metadata_type size_t void ITT_FORMAT p const __itt_domain __itt_id __itt_string_handle const wchar_t size_t ITT_FORMAT lu const __itt_domain __itt_id __itt_relation __itt_id ITT_FORMAT p const wchar_t int ITT_FORMAT __itt_group_mark d int
task_stream< num_priority_levels > my_task_stream
Task pool for the tasks scheduled via task::enqueue() method.
Definition: arena.h:80
void set_is_idle(bool value)
Indicate whether thread that reads this mailbox is idle.
Definition: mailbox.h:215
bool is_idle_state(bool value) const
Indicate whether thread that reads this mailbox is idle.
Definition: mailbox.h:222
#define __TBB_control_consistency_helper()
Definition: gcc_generic.h:64
unsigned num_workers_active()
The number of workers active in the arena.
Definition: arena.h:237
affinity_id my_affinity_id
The mailbox id assigned to this scheduler.
Definition: scheduler.h:93
unsigned hint_for_pop
Hint provided for operations with the container of starvation-resistant tasks.
bool worker_outermost_level() const
True if the scheduler is on the outermost dispatch level in a worker thread.
Definition: scheduler.h:579
arena * my_arena
The arena that I own (if master) or am servicing at the moment (if worker)
Definition: scheduler.h:78

References __TBB_ASSERT, __TBB_control_consistency_helper, __TBB_ISOLATION_ARG, __TBB_ISOLATION_EXPR, __TBB_Yield, GATHER_STATISTIC, int, tbb::internal::is_critical(), ITT_NOTIFY, tbb::internal::no_isolation, p, tbb::internal::prolonged_pause(), and sync_cancel.

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◆ tally_completion_of_predecessor()

template<typename SchedulerTraits >
void tbb::internal::custom_scheduler< SchedulerTraits >::tally_completion_of_predecessor ( task s,
__TBB_ISOLATION_ARG(task *&bypass_slot, isolation_tag isolation)   
)
inlineprivate

Decrements ref_count of a predecessor.

If it achieves 0, the predecessor is scheduled for execution. When changing, remember that this is a hot path function.

Definition at line 76 of file custom_scheduler.h.

76  {
77  task_prefix& p = s.prefix();
78  if( SchedulerTraits::itt_possible )
79  ITT_NOTIFY(sync_releasing, &p.ref_count);
80  if( SchedulerTraits::has_slow_atomic && p.ref_count==1 )
81  p.ref_count=0;
82  else if( __TBB_FetchAndDecrementWrelease(&p.ref_count) > 1 ) {// more references exist
83  // '__TBB_cl_evict(&p)' degraded performance of parallel_preorder example
84  return;
85  }
86 
87  // Ordering on p.ref_count (superfluous if SchedulerTraits::has_slow_atomic)
89  __TBB_ASSERT(p.ref_count==0, "completion of task caused predecessor's reference count to underflow");
90  if( SchedulerTraits::itt_possible )
91  ITT_NOTIFY(sync_acquired, &p.ref_count);
92 #if TBB_USE_ASSERT
93  p.extra_state &= ~es_ref_count_active;
94 #endif /* TBB_USE_ASSERT */
95 #if __TBB_TASK_ISOLATION
96  if ( isolation != no_isolation ) {
97  // The parent is allowed not to have isolation (even if a child has isolation) because it has never spawned.
98  __TBB_ASSERT(p.isolation == no_isolation || p.isolation == isolation, NULL);
99  p.isolation = isolation;
100  }
101 #endif /* __TBB_TASK_ISOLATION */
102 
103 #if __TBB_RECYCLE_TO_ENQUEUE
104  if (p.state==task::to_enqueue) {
105  // related to __TBB_TASK_ARENA TODO: try keep priority of the task
106  // e.g. rework task_prefix to remember priority of received task and use here
108  } else
109 #endif /*__TBB_RECYCLE_TO_ENQUEUE*/
110  if( bypass_slot==NULL )
111  bypass_slot = &s;
112 #if __TBB_PREVIEW_CRITICAL_TASKS
113  else if( internal::is_critical( s ) ) {
114  local_spawn( bypass_slot, bypass_slot->prefix().next );
115  bypass_slot = &s;
116  }
117 #endif /* __TBB_PREVIEW_CRITICAL_TASKS */
118  else
119  local_spawn( &s, s.prefix().next );
120  }
Set if ref_count might be changed by another thread. Used for debugging.
#define __TBB_FetchAndDecrementWrelease(P)
Definition: tbb_machine.h:315
#define __TBB_ASSERT(predicate, comment)
No-op version of __TBB_ASSERT.
Definition: tbb_stddef.h:169
const isolation_tag no_isolation
Definition: task.h:129
FastRandom my_random
Random number generator used for picking a random victim from which to steal.
Definition: scheduler.h:162
void enqueue_task(task &, intptr_t, FastRandom &)
enqueue a task into starvation-resistance queue
Definition: arena.cpp:558
void const char const char int ITT_FORMAT __itt_group_sync p
bool is_critical(task &t)
Definition: task.h:953
void local_spawn(task *first, task *&next)
Definition: scheduler.cpp:618
void const char const char int ITT_FORMAT __itt_group_sync x void const char ITT_FORMAT __itt_group_sync s void ITT_FORMAT __itt_group_sync p void ITT_FORMAT p sync_releasing
#define ITT_NOTIFY(name, obj)
Definition: itt_notify.h:120
void const char const char int ITT_FORMAT __itt_group_sync s
#define __TBB_control_consistency_helper()
Definition: gcc_generic.h:64
arena * my_arena
The arena that I own (if master) or am servicing at the moment (if worker)
Definition: scheduler.h:78

References __TBB_ASSERT, __TBB_control_consistency_helper, __TBB_FetchAndDecrementWrelease, tbb::internal::arena::enqueue_task(), tbb::internal::es_ref_count_active, tbb::internal::is_critical(), ITT_NOTIFY, tbb::internal::generic_scheduler::local_spawn(), tbb::internal::scheduler_state::my_arena, tbb::internal::generic_scheduler::my_random, tbb::internal::no_isolation, p, tbb::task::prefix(), s, and sync_releasing.

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◆ wait_for_all()

template<typename SchedulerTraits >
void tbb::internal::custom_scheduler< SchedulerTraits >::wait_for_all ( task parent,
task child 
)
inlineprivatevirtual

Entry point from client code to the scheduler loop that dispatches tasks.

The method is virtual, but the *this object is used only for sake of dispatching on the correct vtable, not necessarily the correct *this object. The correct *this object is looked up in TLS.

Implements tbb::internal::scheduler.

Definition at line 69 of file custom_scheduler.h.

69  {
70  static_cast<custom_scheduler*>(governor::local_scheduler())->scheduler_type::local_wait_for_all( parent, child );
71  }
static generic_scheduler * local_scheduler()
Obtain the thread-local instance of the TBB scheduler.
Definition: governor.h:126
void const char const char int ITT_FORMAT __itt_group_sync x void const char ITT_FORMAT __itt_group_sync s void ITT_FORMAT __itt_group_sync p void ITT_FORMAT p void ITT_FORMAT p no args __itt_suppress_mode_t unsigned int void size_t ITT_FORMAT d void ITT_FORMAT p void ITT_FORMAT p __itt_model_site __itt_model_site_instance ITT_FORMAT p __itt_model_task __itt_model_task_instance ITT_FORMAT p void ITT_FORMAT p void ITT_FORMAT p void size_t ITT_FORMAT d void ITT_FORMAT p const wchar_t ITT_FORMAT s const char ITT_FORMAT s const char ITT_FORMAT s const char ITT_FORMAT s no args void ITT_FORMAT p size_t ITT_FORMAT d no args const wchar_t const wchar_t ITT_FORMAT s __itt_heap_function void size_t int ITT_FORMAT d __itt_heap_function void ITT_FORMAT p __itt_heap_function void void size_t int ITT_FORMAT d no args no args unsigned int ITT_FORMAT u const __itt_domain __itt_id ITT_FORMAT lu const __itt_domain __itt_id __itt_id parent

References tbb::internal::governor::local_scheduler(), and parent.

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The documentation for this class was generated from the following file:

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