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/*************************************************************************/
/* worker_thread_pool.cpp */
/*************************************************************************/
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/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md). */
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/* the following conditions: */
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/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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# include "worker_thread_pool.h"
# include "core/os/os.h"
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void WorkerThreadPool : : Task : : free_template_userdata ( ) {
ERR_FAIL_COND ( ! template_userdata ) ;
ERR_FAIL_COND ( native_func_userdata = = nullptr ) ;
BaseTemplateUserdata * btu = ( BaseTemplateUserdata * ) native_func_userdata ;
memdelete ( btu ) ;
}
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WorkerThreadPool * WorkerThreadPool : : singleton = nullptr ;
void WorkerThreadPool : : _process_task_queue ( ) {
task_mutex . lock ( ) ;
Task * task = task_queue . first ( ) - > self ( ) ;
task_queue . remove ( task_queue . first ( ) ) ;
task_mutex . unlock ( ) ;
_process_task ( task ) ;
}
void WorkerThreadPool : : _process_task ( Task * p_task ) {
bool low_priority = p_task - > low_priority ;
if ( p_task - > group ) {
// Handling a group
bool do_post = false ;
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Callable : : CallError ce ;
Variant ret ;
Variant arg ;
Variant * argptr = & arg ;
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while ( true ) {
uint32_t work_index = p_task - > group - > index . postincrement ( ) ;
if ( work_index > = p_task - > group - > max ) {
break ;
}
if ( p_task - > native_group_func ) {
p_task - > native_group_func ( p_task - > native_func_userdata , work_index ) ;
} else if ( p_task - > template_userdata ) {
p_task - > template_userdata - > callback_indexed ( work_index ) ;
} else {
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arg = work_index ;
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p_task - > callable . callp ( ( const Variant * * ) & argptr , 1 , ret , ce ) ;
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}
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// This is the only way to ensure posting is done when all tasks are really complete.
uint32_t completed_amount = p_task - > group - > completed_index . increment ( ) ;
if ( completed_amount = = p_task - > group - > max ) {
do_post = true ;
}
}
if ( do_post & & p_task - > template_userdata ) {
memdelete ( p_task - > template_userdata ) ; // This is no longer needed at this point, so get rid of it.
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}
if ( low_priority & & use_native_low_priority_threads ) {
p_task - > completed = true ;
p_task - > done_semaphore . post ( ) ;
if ( do_post ) {
p_task - > group - > completed . set_to ( true ) ;
}
} else {
if ( do_post ) {
p_task - > group - > done_semaphore . post ( ) ;
p_task - > group - > completed . set_to ( true ) ;
}
uint32_t max_users = p_task - > group - > tasks_used + 1 ; // Add 1 because the thread waiting for it is also user. Read before to avoid another thread freeing task after increment.
uint32_t finished_users = p_task - > group - > finished . increment ( ) ;
if ( finished_users = = max_users ) {
// Get rid of the group, because nobody else is using it.
task_mutex . lock ( ) ;
group_allocator . free ( p_task - > group ) ;
task_mutex . unlock ( ) ;
}
// For groups, tasks get rid of themselves.
task_mutex . lock ( ) ;
task_allocator . free ( p_task ) ;
task_mutex . unlock ( ) ;
}
} else {
if ( p_task - > native_func ) {
p_task - > native_func ( p_task - > native_func_userdata ) ;
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} else if ( p_task - > template_userdata ) {
p_task - > template_userdata - > callback ( ) ;
memdelete ( p_task - > template_userdata ) ;
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} else {
Callable : : CallError ce ;
Variant ret ;
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p_task - > callable . callp ( nullptr , 0 , ret , ce ) ;
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}
p_task - > completed = true ;
p_task - > done_semaphore . post ( ) ;
}
if ( ! use_native_low_priority_threads & & low_priority ) {
// A low prioriry task was freed, so see if we can move a pending one to the high priority queue.
bool post = false ;
task_mutex . lock ( ) ;
if ( low_priority_task_queue . first ( ) ) {
Task * low_prio_task = low_priority_task_queue . first ( ) - > self ( ) ;
low_priority_task_queue . remove ( low_priority_task_queue . first ( ) ) ;
task_queue . add_last ( & low_prio_task - > task_elem ) ;
post = true ;
} else {
low_priority_threads_used . decrement ( ) ;
}
task_mutex . lock ( ) ;
if ( post ) {
task_available_semaphore . post ( ) ;
}
}
}
void WorkerThreadPool : : _thread_function ( void * p_user ) {
while ( true ) {
singleton - > task_available_semaphore . wait ( ) ;
if ( singleton - > exit_threads . is_set ( ) ) {
break ;
}
singleton - > _process_task_queue ( ) ;
}
}
void WorkerThreadPool : : _native_low_priority_thread_function ( void * p_user ) {
Task * task = ( Task * ) p_user ;
singleton - > _process_task ( task ) ;
}
void WorkerThreadPool : : _post_task ( Task * p_task , bool p_high_priority ) {
task_mutex . lock ( ) ;
p_task - > low_priority = ! p_high_priority ;
if ( ! p_high_priority & & use_native_low_priority_threads ) {
task_mutex . unlock ( ) ;
p_task - > low_priority_thread = native_thread_allocator . alloc ( ) ;
p_task - > low_priority_thread - > start ( _native_low_priority_thread_function , p_task ) ; // Pask task directly to thread.
} else if ( p_high_priority | | low_priority_threads_used . get ( ) < max_low_priority_threads ) {
task_queue . add_last ( & p_task - > task_elem ) ;
if ( ! p_high_priority ) {
low_priority_threads_used . increment ( ) ;
}
task_mutex . unlock ( ) ;
task_available_semaphore . post ( ) ;
} else {
// Too many threads using low priority, must go to queue.
low_priority_task_queue . add_last ( & p_task - > task_elem ) ;
task_mutex . unlock ( ) ;
}
}
WorkerThreadPool : : TaskID WorkerThreadPool : : add_native_task ( void ( * p_func ) ( void * ) , void * p_userdata , bool p_high_priority , const String & p_description ) {
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return _add_task ( Callable ( ) , p_func , p_userdata , nullptr , p_high_priority , p_description ) ;
}
WorkerThreadPool : : TaskID WorkerThreadPool : : _add_task ( const Callable & p_callable , void ( * p_func ) ( void * ) , void * p_userdata , BaseTemplateUserdata * p_template_userdata , bool p_high_priority , const String & p_description ) {
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task_mutex . lock ( ) ;
// Get a free task
Task * task = task_allocator . alloc ( ) ;
TaskID id = last_task + + ;
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task - > callable = p_callable ;
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task - > native_func = p_func ;
task - > native_func_userdata = p_userdata ;
task - > description = p_description ;
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task - > template_userdata = p_template_userdata ;
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tasks . insert ( id , task ) ;
task_mutex . unlock ( ) ;
_post_task ( task , p_high_priority ) ;
return id ;
}
WorkerThreadPool : : TaskID WorkerThreadPool : : add_task ( const Callable & p_action , bool p_high_priority , const String & p_description ) {
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return _add_task ( p_action , nullptr , nullptr , nullptr , p_high_priority , p_description ) ;
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}
bool WorkerThreadPool : : is_task_completed ( TaskID p_task_id ) const {
task_mutex . lock ( ) ;
const Task * const * taskp = tasks . getptr ( p_task_id ) ;
if ( ! taskp ) {
task_mutex . unlock ( ) ;
ERR_FAIL_V_MSG ( false , " Invalid Task ID " ) ; // Invalid task
}
bool completed = ( * taskp ) - > completed ;
task_mutex . unlock ( ) ;
return completed ;
}
void WorkerThreadPool : : wait_for_task_completion ( TaskID p_task_id ) {
task_mutex . lock ( ) ;
Task * * taskp = tasks . getptr ( p_task_id ) ;
if ( ! taskp ) {
task_mutex . unlock ( ) ;
ERR_FAIL_MSG ( " Invalid Task ID " ) ; // Invalid task
}
Task * task = * taskp ;
if ( task - > waiting ) {
String description = task - > description ;
task_mutex . unlock ( ) ;
if ( description . is_empty ( ) ) {
ERR_FAIL_MSG ( " Another thread is waiting on this task: " + itos ( p_task_id ) ) ; // Invalid task
} else {
ERR_FAIL_MSG ( " Another thread is waiting on this task: " + description + " ( " + itos ( p_task_id ) + " ) " ) ; // Invalid task
}
}
task - > waiting = true ;
task_mutex . unlock ( ) ;
if ( use_native_low_priority_threads & & task - > low_priority ) {
task - > low_priority_thread - > wait_to_finish ( ) ;
native_thread_allocator . free ( task - > low_priority_thread ) ;
} else {
int * index = thread_ids . getptr ( Thread : : get_caller_id ( ) ) ;
if ( index ) {
// We are an actual process thread, we must not be blocked so continue processing stuff if available.
while ( true ) {
if ( task - > done_semaphore . try_wait ( ) ) {
// If done, exit
break ;
}
if ( task_available_semaphore . try_wait ( ) ) {
// Solve tasks while they are around.
_process_task_queue ( ) ;
continue ;
}
OS : : get_singleton ( ) - > delay_usec ( 1 ) ; // Microsleep, this could be converted to waiting for multiple objects in supported platforms for a bit more performance.
}
} else {
task - > done_semaphore . wait ( ) ;
}
}
task_mutex . lock ( ) ;
tasks . erase ( p_task_id ) ;
task_allocator . free ( task ) ;
task_mutex . unlock ( ) ;
}
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WorkerThreadPool : : GroupID WorkerThreadPool : : _add_group_task ( const Callable & p_callable , void ( * p_func ) ( void * , uint32_t ) , void * p_userdata , BaseTemplateUserdata * p_template_userdata , int p_elements , int p_tasks , bool p_high_priority , const String & p_description ) {
ERR_FAIL_COND_V ( p_elements < 0 , INVALID_TASK_ID ) ;
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if ( p_tasks < 0 ) {
p_tasks = threads . size ( ) ;
}
task_mutex . lock ( ) ;
Group * group = group_allocator . alloc ( ) ;
GroupID id = last_task + + ;
group - > max = p_elements ;
group - > self = id ;
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Task * * tasks_posted = nullptr ;
if ( p_elements = = 0 ) {
// Should really not call it with zero Elements, but at least it should work.
group - > completed . set_to ( true ) ;
group - > done_semaphore . post ( ) ;
group - > tasks_used = 0 ;
p_tasks = 0 ;
if ( p_template_userdata ) {
memdelete ( p_template_userdata ) ;
}
} else {
group - > tasks_used = p_tasks ;
tasks_posted = ( Task * * ) alloca ( sizeof ( Task * ) * p_tasks ) ;
for ( int i = 0 ; i < p_tasks ; i + + ) {
Task * task = task_allocator . alloc ( ) ;
task - > native_group_func = p_func ;
task - > native_func_userdata = p_userdata ;
task - > description = p_description ;
task - > group = group ;
task - > callable = p_callable ;
task - > template_userdata = p_template_userdata ;
tasks_posted [ i ] = task ;
// No task ID is used.
}
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}
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groups [ id ] = group ;
task_mutex . unlock ( ) ;
if ( ! p_high_priority & & use_native_low_priority_threads ) {
group - > low_priority_native_tasks . resize ( p_tasks ) ;
}
for ( int i = 0 ; i < p_tasks ; i + + ) {
_post_task ( tasks_posted [ i ] , p_high_priority ) ;
if ( ! p_high_priority & & use_native_low_priority_threads ) {
group - > low_priority_native_tasks [ i ] = tasks_posted [ i ] ;
}
}
return id ;
}
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WorkerThreadPool : : GroupID WorkerThreadPool : : add_native_group_task ( void ( * p_func ) ( void * , uint32_t ) , void * p_userdata , int p_elements , int p_tasks , bool p_high_priority , const String & p_description ) {
return _add_group_task ( Callable ( ) , p_func , p_userdata , nullptr , p_elements , p_tasks , p_high_priority , p_description ) ;
}
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WorkerThreadPool : : GroupID WorkerThreadPool : : add_group_task ( const Callable & p_action , int p_elements , int p_tasks , bool p_high_priority , const String & p_description ) {
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return _add_group_task ( p_action , nullptr , nullptr , nullptr , p_elements , p_tasks , p_high_priority , p_description ) ;
}
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uint32_t WorkerThreadPool : : get_group_processed_element_count ( GroupID p_group ) const {
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task_mutex . lock ( ) ;
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const Group * const * groupp = groups . getptr ( p_group ) ;
if ( ! groupp ) {
task_mutex . unlock ( ) ;
ERR_FAIL_V_MSG ( 0 , " Invalid Group ID " ) ;
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}
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uint32_t elements = ( * groupp ) - > completed_index . get ( ) ;
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task_mutex . unlock ( ) ;
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return elements ;
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}
bool WorkerThreadPool : : is_group_task_completed ( GroupID p_group ) const {
task_mutex . lock ( ) ;
const Group * const * groupp = groups . getptr ( p_group ) ;
if ( ! groupp ) {
task_mutex . unlock ( ) ;
ERR_FAIL_V_MSG ( false , " Invalid Group ID " ) ;
}
bool completed = ( * groupp ) - > completed . is_set ( ) ;
task_mutex . unlock ( ) ;
return completed ;
}
void WorkerThreadPool : : wait_for_group_task_completion ( GroupID p_group ) {
task_mutex . lock ( ) ;
Group * * groupp = groups . getptr ( p_group ) ;
task_mutex . unlock ( ) ;
if ( ! groupp ) {
ERR_FAIL_MSG ( " Invalid Group ID " ) ;
}
Group * group = * groupp ;
if ( group - > low_priority_native_tasks . size ( ) > 0 ) {
for ( uint32_t i = 0 ; i < group - > low_priority_native_tasks . size ( ) ; i + + ) {
group - > low_priority_native_tasks [ i ] - > low_priority_thread - > wait_to_finish ( ) ;
native_thread_allocator . free ( group - > low_priority_native_tasks [ i ] - > low_priority_thread ) ;
task_mutex . lock ( ) ;
task_allocator . free ( group - > low_priority_native_tasks [ i ] ) ;
task_mutex . unlock ( ) ;
}
task_mutex . lock ( ) ;
group_allocator . free ( group ) ;
task_mutex . unlock ( ) ;
} else {
group - > done_semaphore . wait ( ) ;
uint32_t max_users = group - > tasks_used + 1 ; // Add 1 because the thread waiting for it is also user. Read before to avoid another thread freeing task after increment.
uint32_t finished_users = group - > finished . increment ( ) ; // fetch happens before inc, so increment later.
if ( finished_users = = max_users ) {
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// All tasks using this group are gone (finished before the group), so clear the group too.
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task_mutex . lock ( ) ;
group_allocator . free ( group ) ;
task_mutex . unlock ( ) ;
}
}
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task_mutex . lock ( ) ; // This mutex is needed when Physics 2D and/or 3D is selected to run on a separate thread.
groups . erase ( p_group ) ;
task_mutex . unlock ( ) ;
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}
void WorkerThreadPool : : init ( int p_thread_count , bool p_use_native_threads_low_priority , float p_low_priority_task_ratio ) {
ERR_FAIL_COND ( threads . size ( ) > 0 ) ;
if ( p_thread_count < 0 ) {
p_thread_count = OS : : get_singleton ( ) - > get_default_thread_pool_size ( ) ;
}
if ( p_use_native_threads_low_priority ) {
max_low_priority_threads = 0 ;
} else {
max_low_priority_threads = CLAMP ( p_thread_count * p_low_priority_task_ratio , 1 , p_thread_count ) ;
}
use_native_low_priority_threads = p_use_native_threads_low_priority ;
threads . resize ( p_thread_count ) ;
for ( uint32_t i = 0 ; i < threads . size ( ) ; i + + ) {
threads [ i ] . index = i ;
threads [ i ] . thread . start ( & WorkerThreadPool : : _thread_function , & threads [ i ] ) ;
thread_ids . insert ( threads [ i ] . thread . get_id ( ) , i ) ;
}
}
void WorkerThreadPool : : finish ( ) {
if ( threads . size ( ) = = 0 ) {
return ;
}
task_mutex . lock ( ) ;
SelfList < Task > * E = low_priority_task_queue . first ( ) ;
while ( E ) {
print_error ( " Task waiting was never re-claimed: " + E - > self ( ) - > description ) ;
E = E - > next ( ) ;
}
task_mutex . unlock ( ) ;
exit_threads . set_to ( true ) ;
for ( uint32_t i = 0 ; i < threads . size ( ) ; i + + ) {
task_available_semaphore . post ( ) ;
}
for ( uint32_t i = 0 ; i < threads . size ( ) ; i + + ) {
threads [ i ] . thread . wait_to_finish ( ) ;
}
threads . clear ( ) ;
}
void WorkerThreadPool : : _bind_methods ( ) {
ClassDB : : bind_method ( D_METHOD ( " add_task " , " action " , " high_priority " , " description " ) , & WorkerThreadPool : : add_task , DEFVAL ( false ) , DEFVAL ( String ( ) ) ) ;
ClassDB : : bind_method ( D_METHOD ( " is_task_completed " , " task_id " ) , & WorkerThreadPool : : is_task_completed ) ;
ClassDB : : bind_method ( D_METHOD ( " wait_for_task_completion " , " task_id " ) , & WorkerThreadPool : : wait_for_task_completion ) ;
ClassDB : : bind_method ( D_METHOD ( " add_group_task " , " action " , " elements " , " tasks_needed " , " high_priority " , " description " ) , & WorkerThreadPool : : add_group_task , DEFVAL ( - 1 ) , DEFVAL ( false ) , DEFVAL ( String ( ) ) ) ;
ClassDB : : bind_method ( D_METHOD ( " is_group_task_completed " , " group_id " ) , & WorkerThreadPool : : is_group_task_completed ) ;
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ClassDB : : bind_method ( D_METHOD ( " get_group_processed_element_count " , " group_id " ) , & WorkerThreadPool : : get_group_processed_element_count ) ;
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ClassDB : : bind_method ( D_METHOD ( " wait_for_group_task_completion " , " group_id " ) , & WorkerThreadPool : : wait_for_group_task_completion ) ;
}
WorkerThreadPool : : WorkerThreadPool ( ) {
singleton = this ;
}
WorkerThreadPool : : ~ WorkerThreadPool ( ) {
finish ( ) ;
}