1 /* GLIB - Library of useful routines for C programming
2 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
4 * GThreadPool: thread pool implementation.
5 * Copyright (C) 2000 Sebastian Wilhelmi; University of Karlsruhe
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 * Boston, MA 02111-1307, USA.
29 #include "gthreadpool.h"
31 #include "gasyncqueue.h"
32 #include "gasyncqueueprivate.h"
34 #include "gtestutils.h"
38 * SECTION:thread_pools
39 * @title: Thread Pools
40 * @short_description: pools of threads to execute work concurrently
43 * Sometimes you wish to asynchronously fork out the execution of work
44 * and continue working in your own thread. If that will happen often,
45 * the overhead of starting and destroying a thread each time might be
46 * too high. In such cases reusing already started threads seems like a
47 * good idea. And it indeed is, but implementing this can be tedious
50 * Therefore GLib provides thread pools for your convenience. An added
51 * advantage is, that the threads can be shared between the different
52 * subsystems of your program, when they are using GLib.
54 * To create a new thread pool, you use g_thread_pool_new().
55 * It is destroyed by g_thread_pool_free().
57 * If you want to execute a certain task within a thread pool,
58 * you call g_thread_pool_push().
60 * To get the current number of running threads you call
61 * g_thread_pool_get_num_threads(). To get the number of still
62 * unprocessed tasks you call g_thread_pool_unprocessed(). To control
63 * the maximal number of threads for a thread pool, you use
64 * g_thread_pool_get_max_threads() and g_thread_pool_set_max_threads().
66 * Finally you can control the number of unused threads, that are kept
67 * alive by GLib for future use. The current number can be fetched with
68 * g_thread_pool_get_num_unused_threads(). The maximal number can be
69 * controlled by g_thread_pool_get_max_unused_threads() and
70 * g_thread_pool_set_max_unused_threads(). All currently unused threads
71 * can be stopped by calling g_thread_pool_stop_unused_threads().
75 /* #define DEBUG_MSG(args) g_printerr args ; g_printerr ("\n"); */
77 typedef struct _GRealThreadPool GRealThreadPool
;
81 * @func: the function to execute in the threads of this pool
82 * @user_data: the user data for the threads of this pool
83 * @exclusive: are all threads exclusive to this pool
85 * The #GThreadPool struct represents a thread pool. It has three
86 * public read-only members, but the underlying struct is bigger,
87 * so you must not copy this struct.
89 struct _GRealThreadPool
99 GCompareDataFunc sort_func
;
100 gpointer sort_user_data
;
103 /* The following is just an address to mark the wakeup order for a
104 * thread, it could be any address (as long, as it isn't a valid
105 * GThreadPool address)
107 static const gpointer wakeup_thread_marker
= (gpointer
) &g_thread_pool_new
;
108 static gint wakeup_thread_serial
= 0;
110 /* Here all unused threads are waiting */
111 static GAsyncQueue
*unused_thread_queue
= NULL
;
112 static gint unused_threads
= 0;
113 static gint max_unused_threads
= 0;
114 static gint kill_unused_threads
= 0;
115 static guint max_idle_time
= 0;
117 static void g_thread_pool_queue_push_unlocked (GRealThreadPool
*pool
,
119 static void g_thread_pool_free_internal (GRealThreadPool
*pool
);
120 static gpointer
g_thread_pool_thread_proxy (gpointer data
);
121 static gboolean
g_thread_pool_start_thread (GRealThreadPool
*pool
,
123 static void g_thread_pool_wakeup_and_stop_all (GRealThreadPool
*pool
);
124 static GRealThreadPool
* g_thread_pool_wait_for_new_pool (void);
125 static gpointer
g_thread_pool_wait_for_new_task (GRealThreadPool
*pool
);
128 g_thread_pool_queue_push_unlocked (GRealThreadPool
*pool
,
132 g_async_queue_push_sorted_unlocked (pool
->queue
,
135 pool
->sort_user_data
);
137 g_async_queue_push_unlocked (pool
->queue
, data
);
140 static GRealThreadPool
*
141 g_thread_pool_wait_for_new_pool (void)
143 GRealThreadPool
*pool
;
144 gint local_wakeup_thread_serial
;
145 guint local_max_unused_threads
;
146 gint local_max_idle_time
;
147 gint last_wakeup_thread_serial
;
148 gboolean have_relayed_thread_marker
= FALSE
;
150 local_max_unused_threads
= g_atomic_int_get (&max_unused_threads
);
151 local_max_idle_time
= g_atomic_int_get (&max_idle_time
);
152 last_wakeup_thread_serial
= g_atomic_int_get (&wakeup_thread_serial
);
154 g_atomic_int_inc (&unused_threads
);
158 if (g_atomic_int_get (&unused_threads
) >= local_max_unused_threads
)
160 /* If this is a superfluous thread, stop it. */
163 else if (local_max_idle_time
> 0)
165 /* If a maximal idle time is given, wait for the given time. */
166 DEBUG_MSG (("thread %p waiting in global pool for %f seconds.",
167 g_thread_self (), local_max_idle_time
/ 1000.0));
169 pool
= g_async_queue_timeout_pop (unused_thread_queue
,
170 local_max_idle_time
* 1000);
174 /* If no maximal idle time is given, wait indefinitely. */
175 DEBUG_MSG (("thread %p waiting in global pool.", g_thread_self ()));
176 pool
= g_async_queue_pop (unused_thread_queue
);
179 if (pool
== wakeup_thread_marker
)
181 local_wakeup_thread_serial
= g_atomic_int_get (&wakeup_thread_serial
);
182 if (last_wakeup_thread_serial
== local_wakeup_thread_serial
)
184 if (!have_relayed_thread_marker
)
186 /* If this wakeup marker has been received for
187 * the second time, relay it.
189 DEBUG_MSG (("thread %p relaying wakeup message to "
190 "waiting thread with lower serial.",
193 g_async_queue_push (unused_thread_queue
, wakeup_thread_marker
);
194 have_relayed_thread_marker
= TRUE
;
196 /* If a wakeup marker has been relayed, this thread
197 * will get out of the way for 100 microseconds to
198 * avoid receiving this marker again.
205 if (g_atomic_int_add (&kill_unused_threads
, -1) > 0)
211 DEBUG_MSG (("thread %p updating to new limits.",
214 local_max_unused_threads
= g_atomic_int_get (&max_unused_threads
);
215 local_max_idle_time
= g_atomic_int_get (&max_idle_time
);
216 last_wakeup_thread_serial
= local_wakeup_thread_serial
;
218 have_relayed_thread_marker
= FALSE
;
222 while (pool
== wakeup_thread_marker
);
224 g_atomic_int_add (&unused_threads
, -1);
230 g_thread_pool_wait_for_new_task (GRealThreadPool
*pool
)
232 gpointer task
= NULL
;
234 if (pool
->running
|| (!pool
->immediate
&&
235 g_async_queue_length_unlocked (pool
->queue
) > 0))
237 /* This thread pool is still active. */
238 if (pool
->num_threads
> pool
->max_threads
&& pool
->max_threads
!= -1)
240 /* This is a superfluous thread, so it goes to the global pool. */
241 DEBUG_MSG (("superfluous thread %p in pool %p.",
242 g_thread_self (), pool
));
244 else if (pool
->pool
.exclusive
)
246 /* Exclusive threads stay attached to the pool. */
247 task
= g_async_queue_pop_unlocked (pool
->queue
);
249 DEBUG_MSG (("thread %p in exclusive pool %p waits for task "
250 "(%d running, %d unprocessed).",
251 g_thread_self (), pool
, pool
->num_threads
,
252 g_async_queue_length_unlocked (pool
->queue
)));
256 /* A thread will wait for new tasks for at most 1/2
257 * second before going to the global pool.
259 DEBUG_MSG (("thread %p in pool %p waits for up to a 1/2 second for task "
260 "(%d running, %d unprocessed).",
261 g_thread_self (), pool
, pool
->num_threads
,
262 g_async_queue_length_unlocked (pool
->queue
)));
264 task
= g_async_queue_timeout_pop_unlocked (pool
->queue
,
270 /* This thread pool is inactive, it will no longer process tasks. */
271 DEBUG_MSG (("pool %p not active, thread %p will go to global pool "
272 "(running: %s, immediate: %s, len: %d).",
273 pool
, g_thread_self (),
274 pool
->running
? "true" : "false",
275 pool
->immediate
? "true" : "false",
276 g_async_queue_length_unlocked (pool
->queue
)));
284 g_thread_pool_thread_proxy (gpointer data
)
286 GRealThreadPool
*pool
;
290 DEBUG_MSG (("thread %p started for pool %p.", g_thread_self (), pool
));
292 g_async_queue_lock (pool
->queue
);
298 task
= g_thread_pool_wait_for_new_task (pool
);
301 if (pool
->running
|| !pool
->immediate
)
303 /* A task was received and the thread pool is active,
304 * so execute the function.
306 g_async_queue_unlock (pool
->queue
);
307 DEBUG_MSG (("thread %p in pool %p calling func.",
308 g_thread_self (), pool
));
309 pool
->pool
.func (task
, pool
->pool
.user_data
);
310 g_async_queue_lock (pool
->queue
);
315 /* No task was received, so this thread goes to the global pool. */
316 gboolean free_pool
= FALSE
;
318 DEBUG_MSG (("thread %p leaving pool %p for global pool.",
319 g_thread_self (), pool
));
326 if (pool
->num_threads
== 0)
328 /* If the pool is not running and no other
329 * thread is waiting for this thread pool to
330 * finish and this is the last thread of this
331 * pool, free the pool.
337 /* If the pool is not running and no other
338 * thread is waiting for this thread pool to
339 * finish and this is not the last thread of
340 * this pool and there are no tasks left in the
341 * queue, wakeup the remaining threads.
343 if (g_async_queue_length_unlocked (pool
->queue
) ==
345 g_thread_pool_wakeup_and_stop_all (pool
);
348 else if (pool
->immediate
||
349 g_async_queue_length_unlocked (pool
->queue
) <= 0)
351 /* If the pool is not running and another thread is
352 * waiting for this thread pool to finish and there
353 * are either no tasks left or the pool shall stop
354 * immediately, inform the waiting thread of a change
355 * of the thread pool state.
357 g_cond_broadcast (&pool
->cond
);
361 g_async_queue_unlock (pool
->queue
);
364 g_thread_pool_free_internal (pool
);
366 if ((pool
= g_thread_pool_wait_for_new_pool ()) == NULL
)
369 g_async_queue_lock (pool
->queue
);
371 DEBUG_MSG (("thread %p entering pool %p from global pool.",
372 g_thread_self (), pool
));
374 /* pool->num_threads++ is not done here, but in
375 * g_thread_pool_start_thread to make the new started
376 * thread known to the pool before itself can do it.
385 g_thread_pool_start_thread (GRealThreadPool
*pool
,
388 gboolean success
= FALSE
;
390 if (pool
->num_threads
>= pool
->max_threads
&& pool
->max_threads
!= -1)
391 /* Enough threads are already running */
394 g_async_queue_lock (unused_thread_queue
);
396 if (g_async_queue_length_unlocked (unused_thread_queue
) < 0)
398 g_async_queue_push_unlocked (unused_thread_queue
, pool
);
402 g_async_queue_unlock (unused_thread_queue
);
408 /* No thread was found, we have to start a new one */
409 thread
= g_thread_try_new ("pool", g_thread_pool_thread_proxy
, pool
, error
);
414 g_thread_unref (thread
);
417 /* See comment in g_thread_pool_thread_proxy as to why this is done
427 * @func: a function to execute in the threads of the new thread pool
428 * @user_data: user data that is handed over to @func every time it
430 * @max_threads: the maximal number of threads to execute concurrently
431 * in the new thread pool, -1 means no limit
432 * @exclusive: should this thread pool be exclusive?
433 * @error: return location for error, or %NULL
435 * This function creates a new thread pool.
437 * Whenever you call g_thread_pool_push(), either a new thread is
438 * created or an unused one is reused. At most @max_threads threads
439 * are running concurrently for this thread pool. @max_threads = -1
440 * allows unlimited threads to be created for this thread pool. The
441 * newly created or reused thread now executes the function @func
442 * with the two arguments. The first one is the parameter to
443 * g_thread_pool_push() and the second one is @user_data.
445 * The parameter @exclusive determines whether the thread pool owns
446 * all threads exclusive or shares them with other thread pools.
447 * If @exclusive is %TRUE, @max_threads threads are started
448 * immediately and they will run exclusively for this thread pool
449 * until it is destroyed by g_thread_pool_free(). If @exclusive is
450 * %FALSE, threads are created when needed and shared between all
451 * non-exclusive thread pools. This implies that @max_threads may
452 * not be -1 for exclusive thread pools.
454 * @error can be %NULL to ignore errors, or non-%NULL to report
455 * errors. An error can only occur when @exclusive is set to %TRUE
456 * and not all @max_threads threads could be created.
458 * Return value: the new #GThreadPool
461 g_thread_pool_new (GFunc func
,
467 GRealThreadPool
*retval
;
468 G_LOCK_DEFINE_STATIC (init
);
470 g_return_val_if_fail (func
, NULL
);
471 g_return_val_if_fail (!exclusive
|| max_threads
!= -1, NULL
);
472 g_return_val_if_fail (max_threads
>= -1, NULL
);
474 retval
= g_new (GRealThreadPool
, 1);
476 retval
->pool
.func
= func
;
477 retval
->pool
.user_data
= user_data
;
478 retval
->pool
.exclusive
= exclusive
;
479 retval
->queue
= g_async_queue_new ();
480 g_cond_init (&retval
->cond
);
481 retval
->max_threads
= max_threads
;
482 retval
->num_threads
= 0;
483 retval
->running
= TRUE
;
484 retval
->immediate
= FALSE
;
485 retval
->waiting
= FALSE
;
486 retval
->sort_func
= NULL
;
487 retval
->sort_user_data
= NULL
;
490 if (!unused_thread_queue
)
491 unused_thread_queue
= g_async_queue_new ();
494 if (retval
->pool
.exclusive
)
496 g_async_queue_lock (retval
->queue
);
498 while (retval
->num_threads
< retval
->max_threads
)
500 GError
*local_error
= NULL
;
502 if (!g_thread_pool_start_thread (retval
, &local_error
))
504 g_propagate_error (error
, local_error
);
509 g_async_queue_unlock (retval
->queue
);
512 return (GThreadPool
*) retval
;
516 * g_thread_pool_push:
517 * @pool: a #GThreadPool
518 * @data: a new task for @pool
519 * @error: return location for error, or %NULL
521 * Inserts @data into the list of tasks to be executed by @pool.
523 * When the number of currently running threads is lower than the
524 * maximal allowed number of threads, a new thread is started (or
525 * reused) with the properties given to g_thread_pool_new().
526 * Otherwise, @data stays in the queue until a thread in this pool
527 * finishes its previous task and processes @data.
529 * @error can be %NULL to ignore errors, or non-%NULL to report
530 * errors. An error can only occur when a new thread couldn't be
531 * created. In that case @data is simply appended to the queue of
534 * Before version 2.32, this function did not return a success status.
536 * Return value: %TRUE on success, %FALSE if an error occurred
539 g_thread_pool_push (GThreadPool
*pool
,
543 GRealThreadPool
*real
;
546 real
= (GRealThreadPool
*) pool
;
548 g_return_val_if_fail (real
, FALSE
);
549 g_return_val_if_fail (real
->running
, FALSE
);
553 g_async_queue_lock (real
->queue
);
555 if (g_async_queue_length_unlocked (real
->queue
) >= 0)
557 /* No thread is waiting in the queue */
558 GError
*local_error
= NULL
;
560 if (!g_thread_pool_start_thread (real
, &local_error
))
562 g_propagate_error (error
, local_error
);
567 g_thread_pool_queue_push_unlocked (real
, data
);
568 g_async_queue_unlock (real
->queue
);
574 * g_thread_pool_set_max_threads:
575 * @pool: a #GThreadPool
576 * @max_threads: a new maximal number of threads for @pool,
577 * or -1 for unlimited
578 * @error: return location for error, or %NULL
580 * Sets the maximal allowed number of threads for @pool.
581 * A value of -1 means that the maximal number of threads
582 * is unlimited. If @pool is an exclusive thread pool, setting
583 * the maximal number of threads to -1 is not allowed.
585 * Setting @max_threads to 0 means stopping all work for @pool.
586 * It is effectively frozen until @max_threads is set to a non-zero
589 * A thread is never terminated while calling @func, as supplied by
590 * g_thread_pool_new(). Instead the maximal number of threads only
591 * has effect for the allocation of new threads in g_thread_pool_push().
592 * A new thread is allocated, whenever the number of currently
593 * running threads in @pool is smaller than the maximal number.
595 * @error can be %NULL to ignore errors, or non-%NULL to report
596 * errors. An error can only occur when a new thread couldn't be
599 * Before version 2.32, this function did not return a success status.
601 * Return value: %TRUE on success, %FALSE if an error occurred
604 g_thread_pool_set_max_threads (GThreadPool
*pool
,
608 GRealThreadPool
*real
;
612 real
= (GRealThreadPool
*) pool
;
614 g_return_val_if_fail (real
, FALSE
);
615 g_return_val_if_fail (real
->running
, FALSE
);
616 g_return_val_if_fail (!real
->pool
.exclusive
|| max_threads
!= -1, FALSE
);
617 g_return_val_if_fail (max_threads
>= -1, FALSE
);
621 g_async_queue_lock (real
->queue
);
623 real
->max_threads
= max_threads
;
626 to_start
= real
->max_threads
- real
->num_threads
;
628 to_start
= g_async_queue_length_unlocked (real
->queue
);
630 for ( ; to_start
> 0; to_start
--)
632 GError
*local_error
= NULL
;
634 if (!g_thread_pool_start_thread (real
, &local_error
))
636 g_propagate_error (error
, local_error
);
642 g_async_queue_unlock (real
->queue
);
648 * g_thread_pool_get_max_threads:
649 * @pool: a #GThreadPool
651 * Returns the maximal number of threads for @pool.
653 * Return value: the maximal number of threads
656 g_thread_pool_get_max_threads (GThreadPool
*pool
)
658 GRealThreadPool
*real
;
661 real
= (GRealThreadPool
*) pool
;
663 g_return_val_if_fail (real
, 0);
664 g_return_val_if_fail (real
->running
, 0);
666 g_async_queue_lock (real
->queue
);
667 retval
= real
->max_threads
;
668 g_async_queue_unlock (real
->queue
);
674 * g_thread_pool_get_num_threads:
675 * @pool: a #GThreadPool
677 * Returns the number of threads currently running in @pool.
679 * Return value: the number of threads currently running
682 g_thread_pool_get_num_threads (GThreadPool
*pool
)
684 GRealThreadPool
*real
;
687 real
= (GRealThreadPool
*) pool
;
689 g_return_val_if_fail (real
, 0);
690 g_return_val_if_fail (real
->running
, 0);
692 g_async_queue_lock (real
->queue
);
693 retval
= real
->num_threads
;
694 g_async_queue_unlock (real
->queue
);
700 * g_thread_pool_unprocessed:
701 * @pool: a #GThreadPool
703 * Returns the number of tasks still unprocessed in @pool.
705 * Return value: the number of unprocessed tasks
708 g_thread_pool_unprocessed (GThreadPool
*pool
)
710 GRealThreadPool
*real
;
713 real
= (GRealThreadPool
*) pool
;
715 g_return_val_if_fail (real
, 0);
716 g_return_val_if_fail (real
->running
, 0);
718 unprocessed
= g_async_queue_length (real
->queue
);
720 return MAX (unprocessed
, 0);
724 * g_thread_pool_free:
725 * @pool: a #GThreadPool
726 * @immediate: should @pool shut down immediately?
727 * @wait_: should the function wait for all tasks to be finished?
729 * Frees all resources allocated for @pool.
731 * If @immediate is %TRUE, no new task is processed for @pool.
732 * Otherwise @pool is not freed before the last task is processed.
733 * Note however, that no thread of this pool is interrupted while
734 * processing a task. Instead at least all still running threads
735 * can finish their tasks before the @pool is freed.
737 * If @wait_ is %TRUE, the functions does not return before all
738 * tasks to be processed (dependent on @immediate, whether all
739 * or only the currently running) are ready.
740 * Otherwise the function returns immediately.
742 * After calling this function @pool must not be used anymore.
745 g_thread_pool_free (GThreadPool
*pool
,
749 GRealThreadPool
*real
;
751 real
= (GRealThreadPool
*) pool
;
753 g_return_if_fail (real
);
754 g_return_if_fail (real
->running
);
756 /* If there's no thread allowed here, there is not much sense in
757 * not stopping this pool immediately, when it's not empty
759 g_return_if_fail (immediate
||
760 real
->max_threads
!= 0 ||
761 g_async_queue_length (real
->queue
) == 0);
763 g_async_queue_lock (real
->queue
);
765 real
->running
= FALSE
;
766 real
->immediate
= immediate
;
767 real
->waiting
= wait_
;
771 while (g_async_queue_length_unlocked (real
->queue
) != -real
->num_threads
&&
772 !(immediate
&& real
->num_threads
== 0))
773 g_cond_wait (&real
->cond
, _g_async_queue_get_mutex (real
->queue
));
776 if (immediate
|| g_async_queue_length_unlocked (real
->queue
) == -real
->num_threads
)
778 /* No thread is currently doing something (and nothing is left
779 * to process in the queue)
781 if (real
->num_threads
== 0)
783 /* No threads left, we clean up */
784 g_async_queue_unlock (real
->queue
);
785 g_thread_pool_free_internal (real
);
789 g_thread_pool_wakeup_and_stop_all (real
);
792 /* The last thread should cleanup the pool */
793 real
->waiting
= FALSE
;
794 g_async_queue_unlock (real
->queue
);
798 g_thread_pool_free_internal (GRealThreadPool
* pool
)
800 g_return_if_fail (pool
);
801 g_return_if_fail (pool
->running
== FALSE
);
802 g_return_if_fail (pool
->num_threads
== 0);
804 g_async_queue_unref (pool
->queue
);
805 g_cond_clear (&pool
->cond
);
811 g_thread_pool_wakeup_and_stop_all (GRealThreadPool
*pool
)
815 g_return_if_fail (pool
);
816 g_return_if_fail (pool
->running
== FALSE
);
817 g_return_if_fail (pool
->num_threads
!= 0);
819 pool
->immediate
= TRUE
;
821 for (i
= 0; i
< pool
->num_threads
; i
++)
822 g_thread_pool_queue_push_unlocked (pool
, GUINT_TO_POINTER (1));
826 * g_thread_pool_set_max_unused_threads:
827 * @max_threads: maximal number of unused threads
829 * Sets the maximal number of unused threads to @max_threads.
830 * If @max_threads is -1, no limit is imposed on the number
834 g_thread_pool_set_max_unused_threads (gint max_threads
)
836 g_return_if_fail (max_threads
>= -1);
838 g_atomic_int_set (&max_unused_threads
, max_threads
);
840 if (max_threads
!= -1)
842 max_threads
-= g_atomic_int_get (&unused_threads
);
845 g_atomic_int_set (&kill_unused_threads
, -max_threads
);
846 g_atomic_int_inc (&wakeup_thread_serial
);
848 g_async_queue_lock (unused_thread_queue
);
852 g_async_queue_push_unlocked (unused_thread_queue
,
853 wakeup_thread_marker
);
855 while (++max_threads
);
857 g_async_queue_unlock (unused_thread_queue
);
863 * g_thread_pool_get_max_unused_threads:
865 * Returns the maximal allowed number of unused threads.
867 * Return value: the maximal number of unused threads
870 g_thread_pool_get_max_unused_threads (void)
872 return g_atomic_int_get (&max_unused_threads
);
876 * g_thread_pool_get_num_unused_threads:
878 * Returns the number of currently unused threads.
880 * Return value: the number of currently unused threads
883 g_thread_pool_get_num_unused_threads (void)
885 return g_atomic_int_get (&unused_threads
);
889 * g_thread_pool_stop_unused_threads:
891 * Stops all currently unused threads. This does not change the
892 * maximal number of unused threads. This function can be used to
893 * regularly stop all unused threads e.g. from g_timeout_add().
896 g_thread_pool_stop_unused_threads (void)
900 oldval
= g_thread_pool_get_max_unused_threads ();
902 g_thread_pool_set_max_unused_threads (0);
903 g_thread_pool_set_max_unused_threads (oldval
);
907 * g_thread_pool_set_sort_function:
908 * @pool: a #GThreadPool
909 * @func: the #GCompareDataFunc used to sort the list of tasks.
910 * This function is passed two tasks. It should return
911 * 0 if the order in which they are handled does not matter,
912 * a negative value if the first task should be processed before
913 * the second or a positive value if the second task should be
915 * @user_data: user data passed to @func
917 * Sets the function used to sort the list of tasks. This allows the
918 * tasks to be processed by a priority determined by @func, and not
919 * just in the order in which they were added to the pool.
921 * Note, if the maximum number of threads is more than 1, the order
922 * that threads are executed cannot be guaranteed 100%. Threads are
923 * scheduled by the operating system and are executed at random. It
924 * cannot be assumed that threads are executed in the order they are
930 g_thread_pool_set_sort_function (GThreadPool
*pool
,
931 GCompareDataFunc func
,
934 GRealThreadPool
*real
;
936 real
= (GRealThreadPool
*) pool
;
938 g_return_if_fail (real
);
939 g_return_if_fail (real
->running
);
941 g_async_queue_lock (real
->queue
);
943 real
->sort_func
= func
;
944 real
->sort_user_data
= user_data
;
947 g_async_queue_sort_unlocked (real
->queue
,
949 real
->sort_user_data
);
951 g_async_queue_unlock (real
->queue
);
955 * g_thread_pool_set_max_idle_time:
956 * @interval: the maximum @interval (in milliseconds)
957 * a thread can be idle
959 * This function will set the maximum @interval that a thread
960 * waiting in the pool for new tasks can be idle for before
961 * being stopped. This function is similar to calling
962 * g_thread_pool_stop_unused_threads() on a regular timeout,
963 * except this is done on a per thread basis.
965 * By setting @interval to 0, idle threads will not be stopped.
967 * This function makes use of g_async_queue_timed_pop () using
973 g_thread_pool_set_max_idle_time (guint interval
)
977 g_atomic_int_set (&max_idle_time
, interval
);
979 i
= g_atomic_int_get (&unused_threads
);
982 g_atomic_int_inc (&wakeup_thread_serial
);
983 g_async_queue_lock (unused_thread_queue
);
987 g_async_queue_push_unlocked (unused_thread_queue
,
988 wakeup_thread_marker
);
992 g_async_queue_unlock (unused_thread_queue
);
997 * g_thread_pool_get_max_idle_time:
999 * This function will return the maximum @interval that a
1000 * thread will wait in the thread pool for new tasks before
1003 * If this function returns 0, threads waiting in the thread
1004 * pool for new work are not stopped.
1006 * Return value: the maximum @interval (milliseconds) to wait
1007 * for new tasks in the thread pool before stopping the
1013 g_thread_pool_get_max_idle_time (void)
1015 return g_atomic_int_get (&max_idle_time
);