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>
15 #define INITIAL_LENGTH 32
16 #define WSQ_DEBUG(...)
17 //#define WSQ_DEBUG(...) g_message(__VA_ARGS__)
27 #define NO_KEY ((guint32) -1)
28 static guint32 wsq_tlskey = NO_KEY;
33 wsq_tlskey = TlsAlloc ();
39 if (wsq_tlskey == NO_KEY)
51 if (wsq_tlskey == NO_KEY)
54 wsq = g_new0 (MonoWSQ, 1);
55 wsq->mask = INITIAL_LENGTH - 1;
56 MONO_GC_REGISTER_ROOT_SINGLE (wsq->queue);
57 root = mono_get_root_domain ();
58 wsq->queue = mono_array_new_cached (root, mono_defaults.object_class, INITIAL_LENGTH);
59 MONO_SEM_INIT (&wsq->lock, 1);
60 if (!TlsSetValue (wsq_tlskey, wsq)) {
61 mono_wsq_destroy (wsq);
68 mono_wsq_destroy (MonoWSQ *wsq)
70 if (wsq == NULL || wsq->queue == NULL)
73 g_assert (mono_wsq_count (wsq) == 0);
74 MONO_GC_UNREGISTER_ROOT (wsq->queue);
75 MONO_SEM_DESTROY (&wsq->lock);
76 memset (wsq, 0, sizeof (MonoWSQ));
77 if (wsq_tlskey != NO_KEY && TlsGetValue (wsq_tlskey) == wsq)
78 TlsSetValue (wsq_tlskey, NULL);
83 mono_wsq_count (MonoWSQ *wsq)
87 return ((wsq->tail - wsq->head) & wsq->mask);
91 mono_wsq_local_push (void *obj)
98 if (obj == NULL || wsq_tlskey == NO_KEY)
101 wsq = (MonoWSQ *) TlsGetValue (wsq_tlskey);
103 WSQ_DEBUG ("local_push: no wsq\n");
108 if (tail < wsq->head + wsq->mask) {
109 mono_array_setref (wsq->queue, tail & wsq->mask, (MonoObject *) obj);
110 wsq->tail = tail + 1;
111 WSQ_DEBUG ("local_push: OK %p %p\n", wsq, obj);
115 MONO_SEM_WAIT (&wsq->lock);
117 count = wsq->tail - wsq->head;
118 if (count >= wsq->mask) {
119 MonoArray *new_array;
123 length = mono_array_length (wsq->queue);
124 new_array = mono_array_new_cached (mono_get_root_domain (), mono_defaults.object_class, length * 2);
125 for (i = 0; i < length; i++)
126 mono_array_setref (new_array, i, mono_array_get (wsq->queue, MonoObject*, (i + head) & wsq->mask));
128 memset (mono_array_addr (wsq->queue, MonoObject *, 0), 0, sizeof (MonoObject*) * length);
129 wsq->queue = new_array;
131 wsq->tail = tail = count;
132 wsq->mask = (wsq->mask << 1) | 1;
134 mono_array_setref (wsq->queue, tail & wsq->mask, obj);
135 wsq->tail = tail + 1;
136 MONO_SEM_POST (&wsq->lock);
137 WSQ_DEBUG ("local_push: LOCK %p %p\n", wsq, obj);
142 mono_wsq_local_pop (void **ptr)
148 if (ptr == NULL || wsq_tlskey == NO_KEY)
151 wsq = (MonoWSQ *) TlsGetValue (wsq_tlskey);
153 WSQ_DEBUG ("local_pop: no wsq\n");
158 if (wsq->head >= tail) {
159 WSQ_DEBUG ("local_pop: empty\n");
163 InterlockedExchange (&wsq->tail, tail);
164 if (wsq->head <= tail) {
165 *ptr = mono_array_get (wsq->queue, void *, tail & wsq->mask);
166 mono_array_set (wsq->queue, void *, tail & wsq->mask, NULL);
167 WSQ_DEBUG ("local_pop: GOT ONE %p %p\n", wsq, *ptr);
171 MONO_SEM_WAIT (&wsq->lock);
172 if (wsq->head <= tail) {
173 *ptr = mono_array_get (wsq->queue, void *, tail & wsq->mask);
174 mono_array_set (wsq->queue, void *, tail & wsq->mask, NULL);
177 wsq->tail = tail + 1;
180 MONO_SEM_POST (&wsq->lock);
181 WSQ_DEBUG ("local_pop: LOCK %d %p %p\n", res, wsq, *ptr);
186 mono_wsq_try_steal (MonoWSQ *wsq, void **ptr, guint32 ms_timeout)
188 if (wsq == NULL || ptr == NULL || *ptr != NULL || wsq_tlskey == NO_KEY)
191 if (TlsGetValue (wsq_tlskey) == wsq)
194 if (mono_sem_timedwait (&wsq->lock, ms_timeout, FALSE) == 0) {
198 InterlockedExchange (&wsq->head, head + 1);
199 if (head < wsq->tail) {
200 *ptr = mono_array_get (wsq->queue, void *, head & wsq->mask);
201 mono_array_set (wsq->queue, void *, head & wsq->mask, NULL);
202 WSQ_DEBUG ("STEAL %p %p\n", wsq, *ptr);
206 MONO_SEM_POST (&wsq->lock);