2 * mono-wsq.c: work-stealing queue
5 * Gonzalo Paniagua Javier (gonzalo@novell.com)
7 * Copyright (c) 2010 Novell, Inc (http://www.novell.com)
11 #include <mono/metadata/object.h>
12 #include <mono/metadata/mono-wsq.h>
13 #include <mono/utils/mono-semaphore.h>
14 #include <mono/utils/mono-tls.h>
16 #define INITIAL_LENGTH 32
17 #define WSQ_DEBUG(...)
18 //#define WSQ_DEBUG(...) g_message(__VA_ARGS__)
28 #define NO_KEY ((guint32) -1)
29 static MonoNativeTlsKey wsq_tlskey;
30 static gboolean wsq_tlskey_inited = FALSE;
35 if (wsq_tlskey_inited)
38 mono_native_tls_alloc (wsq_tlskey, NULL);
39 wsq_tlskey_inited = TRUE;
45 if (!wsq_tlskey_inited)
47 mono_native_tls_free (wsq_tlskey);
48 wsq_tlskey_inited = FALSE;
57 if (!wsq_tlskey_inited)
60 wsq = g_new0 (MonoWSQ, 1);
61 wsq->mask = INITIAL_LENGTH - 1;
62 MONO_GC_REGISTER_ROOT_SINGLE (wsq->queue);
63 root = mono_get_root_domain ();
64 wsq->queue = mono_array_new_cached (root, mono_defaults.object_class, INITIAL_LENGTH);
65 MONO_SEM_INIT (&wsq->lock, 1);
66 if (!mono_native_tls_set_value (wsq_tlskey, wsq)) {
67 mono_wsq_destroy (wsq);
74 mono_wsq_destroy (MonoWSQ *wsq)
76 if (wsq == NULL || wsq->queue == NULL)
79 g_assert (mono_wsq_count (wsq) == 0);
80 MONO_GC_UNREGISTER_ROOT (wsq->queue);
81 MONO_SEM_DESTROY (&wsq->lock);
82 memset (wsq, 0, sizeof (MonoWSQ));
83 if (wsq_tlskey_inited && mono_native_tls_get_value (wsq_tlskey) == wsq)
84 mono_native_tls_set_value (wsq_tlskey, NULL);
89 mono_wsq_count (MonoWSQ *wsq)
93 return ((wsq->tail - wsq->head) & wsq->mask);
97 mono_wsq_local_push (void *obj)
104 if (obj == NULL || !wsq_tlskey_inited)
107 wsq = (MonoWSQ *) mono_native_tls_get_value (wsq_tlskey);
109 WSQ_DEBUG ("local_push: no wsq\n");
114 if (tail < wsq->head + wsq->mask) {
115 mono_array_setref (wsq->queue, tail & wsq->mask, (MonoObject *) obj);
116 wsq->tail = tail + 1;
117 WSQ_DEBUG ("local_push: OK %p %p\n", wsq, obj);
121 MONO_SEM_WAIT (&wsq->lock);
123 count = wsq->tail - wsq->head;
124 if (count >= wsq->mask) {
125 MonoArray *new_array;
129 length = mono_array_length (wsq->queue);
130 new_array = mono_array_new_cached (mono_get_root_domain (), mono_defaults.object_class, length * 2);
131 for (i = 0; i < length; i++)
132 mono_array_setref (new_array, i, mono_array_get (wsq->queue, MonoObject*, (i + head) & wsq->mask));
134 mono_gc_bzero (mono_array_addr (wsq->queue, MonoObject *, 0), sizeof (MonoObject*) * length);
135 wsq->queue = new_array;
137 wsq->tail = tail = count;
138 wsq->mask = (wsq->mask << 1) | 1;
140 mono_array_setref (wsq->queue, tail & wsq->mask, obj);
141 wsq->tail = tail + 1;
142 MONO_SEM_POST (&wsq->lock);
143 WSQ_DEBUG ("local_push: LOCK %p %p\n", wsq, obj);
148 mono_wsq_local_pop (void **ptr)
154 if (ptr == NULL || !wsq_tlskey_inited)
157 wsq = (MonoWSQ *) mono_native_tls_get_value (wsq_tlskey);
159 WSQ_DEBUG ("local_pop: no wsq\n");
164 if (wsq->head >= tail) {
165 WSQ_DEBUG ("local_pop: empty\n");
169 InterlockedExchange (&wsq->tail, tail);
170 if (wsq->head <= tail) {
171 *ptr = mono_array_get (wsq->queue, void *, tail & wsq->mask);
172 mono_array_set (wsq->queue, void *, tail & wsq->mask, NULL);
173 WSQ_DEBUG ("local_pop: GOT ONE %p %p\n", wsq, *ptr);
177 MONO_SEM_WAIT (&wsq->lock);
178 if (wsq->head <= tail) {
179 *ptr = mono_array_get (wsq->queue, void *, tail & wsq->mask);
180 mono_array_set (wsq->queue, void *, tail & wsq->mask, NULL);
183 wsq->tail = tail + 1;
186 MONO_SEM_POST (&wsq->lock);
187 WSQ_DEBUG ("local_pop: LOCK %d %p %p\n", res, wsq, *ptr);
192 mono_wsq_try_steal (MonoWSQ *wsq, void **ptr, guint32 ms_timeout)
194 if (wsq == NULL || ptr == NULL || *ptr != NULL || !wsq_tlskey_inited)
197 if (mono_native_tls_get_value (wsq_tlskey) == wsq)
200 if (mono_sem_timedwait (&wsq->lock, ms_timeout, FALSE) == 0) {
204 InterlockedExchange (&wsq->head, head + 1);
205 if (head < wsq->tail) {
206 *ptr = mono_array_get (wsq->queue, void *, head & wsq->mask);
207 mono_array_set (wsq->queue, void *, head & wsq->mask, NULL);
208 WSQ_DEBUG ("STEAL %p %p\n", wsq, *ptr);
212 MONO_SEM_POST (&wsq->lock);