2 * mono-wsq.c: work-stealing queue
5 * Gonzalo Paniagua Javier (gonzalo@novell.com)
7 * Copyright (c) 2010 Novell, Inc (http://www.novell.com)
8 * Copyright 2011 Xamarin, Inc (http://www.xamarin.com)
12 #include <mono/metadata/object.h>
13 #include <mono/metadata/mono-wsq.h>
14 #include <mono/utils/mono-semaphore.h>
15 #include <mono/utils/mono-tls.h>
17 #define INITIAL_LENGTH 32
18 #define WSQ_DEBUG(...)
19 //#define WSQ_DEBUG(...) g_message(__VA_ARGS__)
29 #define NO_KEY ((guint32) -1)
30 static MonoNativeTlsKey wsq_tlskey;
31 static gboolean wsq_tlskey_inited = FALSE;
36 if (wsq_tlskey_inited)
39 mono_native_tls_alloc (&wsq_tlskey, NULL);
40 wsq_tlskey_inited = TRUE;
46 if (!wsq_tlskey_inited)
48 mono_native_tls_free (wsq_tlskey);
49 wsq_tlskey_inited = FALSE;
58 if (!wsq_tlskey_inited)
61 wsq = g_new0 (MonoWSQ, 1);
62 wsq->mask = INITIAL_LENGTH - 1;
63 MONO_GC_REGISTER_ROOT_SINGLE (wsq->queue);
64 root = mono_get_root_domain ();
65 wsq->queue = mono_array_new_cached (root, mono_defaults.object_class, INITIAL_LENGTH);
66 MONO_SEM_INIT (&wsq->lock, 1);
67 if (!mono_native_tls_set_value (wsq_tlskey, wsq)) {
68 mono_wsq_destroy (wsq);
75 mono_wsq_destroy (MonoWSQ *wsq)
77 if (wsq == NULL || wsq->queue == NULL)
80 g_assert (mono_wsq_count (wsq) == 0);
81 MONO_GC_UNREGISTER_ROOT (wsq->queue);
82 MONO_SEM_DESTROY (&wsq->lock);
83 memset (wsq, 0, sizeof (MonoWSQ));
84 if (wsq_tlskey_inited && mono_native_tls_get_value (wsq_tlskey) == wsq)
85 mono_native_tls_set_value (wsq_tlskey, NULL);
90 mono_wsq_count (MonoWSQ *wsq)
94 return ((wsq->tail - wsq->head) & wsq->mask);
98 mono_wsq_local_push (void *obj)
105 if (obj == NULL || !wsq_tlskey_inited)
108 wsq = (MonoWSQ *) mono_native_tls_get_value (wsq_tlskey);
110 WSQ_DEBUG ("local_push: no wsq\n");
115 if (tail < wsq->head + wsq->mask) {
116 mono_array_setref (wsq->queue, tail & wsq->mask, (MonoObject *) obj);
117 wsq->tail = tail + 1;
118 WSQ_DEBUG ("local_push: OK %p %p\n", wsq, obj);
122 MONO_SEM_WAIT (&wsq->lock);
124 count = wsq->tail - wsq->head;
125 if (count >= wsq->mask) {
126 MonoArray *new_array;
130 length = mono_array_length (wsq->queue);
131 new_array = mono_array_new_cached (mono_get_root_domain (), mono_defaults.object_class, length * 2);
132 for (i = 0; i < length; i++)
133 mono_array_setref (new_array, i, mono_array_get (wsq->queue, MonoObject*, (i + head) & wsq->mask));
135 mono_gc_bzero (mono_array_addr (wsq->queue, MonoObject *, 0), sizeof (MonoObject*) * length);
136 wsq->queue = new_array;
138 wsq->tail = tail = count;
139 wsq->mask = (wsq->mask << 1) | 1;
141 mono_array_setref (wsq->queue, tail & wsq->mask, obj);
142 wsq->tail = tail + 1;
143 MONO_SEM_POST (&wsq->lock);
144 WSQ_DEBUG ("local_push: LOCK %p %p\n", wsq, obj);
149 mono_wsq_local_pop (void **ptr)
155 if (ptr == NULL || !wsq_tlskey_inited)
158 wsq = (MonoWSQ *) mono_native_tls_get_value (wsq_tlskey);
160 WSQ_DEBUG ("local_pop: no wsq\n");
165 if (wsq->head >= tail) {
166 WSQ_DEBUG ("local_pop: empty\n");
170 InterlockedExchange (&wsq->tail, tail);
171 if (wsq->head <= tail) {
172 *ptr = mono_array_get (wsq->queue, void *, tail & wsq->mask);
173 mono_array_set (wsq->queue, void *, tail & wsq->mask, NULL);
174 WSQ_DEBUG ("local_pop: GOT ONE %p %p\n", wsq, *ptr);
178 MONO_SEM_WAIT (&wsq->lock);
179 if (wsq->head <= tail) {
180 *ptr = mono_array_get (wsq->queue, void *, tail & wsq->mask);
181 mono_array_set (wsq->queue, void *, tail & wsq->mask, NULL);
184 wsq->tail = tail + 1;
187 MONO_SEM_POST (&wsq->lock);
188 WSQ_DEBUG ("local_pop: LOCK %d %p %p\n", res, wsq, *ptr);
193 mono_wsq_try_steal (MonoWSQ *wsq, void **ptr, guint32 ms_timeout)
195 if (wsq == NULL || ptr == NULL || *ptr != NULL || !wsq_tlskey_inited)
198 if (mono_native_tls_get_value (wsq_tlskey) == wsq)
201 if (mono_sem_timedwait (&wsq->lock, ms_timeout, FALSE) == 0) {
205 InterlockedExchange (&wsq->head, head + 1);
206 if (head < wsq->tail) {
207 *ptr = mono_array_get (wsq->queue, void *, head & wsq->mask);
208 mono_array_set (wsq->queue, void *, head & wsq->mask, NULL);
209 WSQ_DEBUG ("STEAL %p %p\n", wsq, *ptr);
213 MONO_SEM_POST (&wsq->lock);