#define acquire memory_order_acquire
#define MAX_FREELIST 4 /* Each thread can own up to MAX_FREELIST free nodes */
-#define INITIAL_FREE 2 /* Each thread starts with INITIAL_FREE free nodes */
+#define INITIAL_FREE 3 /* Each thread starts with INITIAL_FREE free nodes */
#define POISON_IDX 0x666
int i;
int t = get_thread_num();
for (i = 0; i < MAX_FREELIST; i++) {
- unsigned int node = load_32(&free_lists[t][i]);
+ //unsigned int node = load_32(&free_lists[t][i]);
+ unsigned int node = free_lists[t][i];
if (node) {
- store_32(&free_lists[t][i], 0);
+ //store_32(&free_lists[t][i], 0);
+ free_lists[t][i] = 0;
return node;
}
}
/* free_list is empty? */
- MODEL_ASSERT(0);
+ //MODEL_ASSERT(0);
return 0;
}
int t = get_thread_num();
/* Don't reclaim NULL node */
- MODEL_ASSERT(node);
+ //MODEL_ASSERT(node);
for (i = 0; i < MAX_FREELIST; i++) {
/* Should never race with our own thread here */
- unsigned int idx = load_32(&free_lists[t][i]);
+ //unsigned int idx = load_32(&free_lists[t][i]);
+ unsigned int idx = free_lists[t][i];
/* Found empty spot in free list */
if (idx == 0) {
store_32(&free_lists[t][i], node);
+ //free_lists[t][i] = node;
return;
}
}
/* free list is full? */
- MODEL_ASSERT(0);
+ //MODEL_ASSERT(0);
}
void init_queue(queue_t *q, int num_threads)
{
- /**
- @Begin
- @Entry_point
- @End
- */
-
int i, j;
+ for (i = 0; i < MAX_NODES; i++) {
+ atomic_init(&q->nodes[i].next, MAKE_POINTER(POISON_IDX, 0));
+ }
/* Initialize each thread's free list with INITIAL_FREE pointers */
/* The actual nodes are initialized with poison indexes */
pointer tmp;
node = new_node();
- store_32(&q->nodes[node].value, val);
+ //store_32(&q->nodes[node].value, val);
+ q->nodes[node].value = val;
tmp = atomic_load_explicit(&q->nodes[node].next, relaxed);
set_ptr(&tmp, 0); // NULL
atomic_store_explicit(&q->nodes[node].next, tmp, relaxed);
while (!success) {
+
+ /**
+ @Begin
+ @Commit_point_clear: true
+ @Label: Enqueue_Clear
+ @End
+ */
+ /**** UL & inadmissible ****/
tail = atomic_load_explicit(&q->tail, acquire);
+ /****FIXME: miss ****/
next = atomic_load_explicit(&q->nodes[get_ptr(tail)].next, acquire);
+ //printf("miss1_enqueue\n");
if (tail == atomic_load_explicit(&q->tail, relaxed)) {
/* Check for uninitialized 'next' */
- MODEL_ASSERT(get_ptr(next) != POISON_IDX);
+ //MODEL_ASSERT(get_ptr(next) != POISON_IDX);
if (get_ptr(next) == 0) { // == NULL
pointer value = MAKE_POINTER(node, get_count(next) + 1);
+ /**** SPEC Error (testcase1.c) ****/
+ // Second release can be just relaxed
success = atomic_compare_exchange_strong_explicit(&q->nodes[get_ptr(tail)].next,
- &next, value, release, release);
+ &next, value, release, relaxed);
+ /**
+ @Begin
+ @Commit_point_define_check: success
+ @Label: EnqueueUpdateNext
+ @End
+ */
}
if (!success) {
+ // This routine helps the other enqueue to update the tail
+ /**** UL & Inadmissible ****/
unsigned int ptr = get_ptr(atomic_load_explicit(&q->nodes[get_ptr(tail)].next, acquire));
pointer value = MAKE_POINTER(ptr,
get_count(tail) + 1);
- int commit_success = 0;
- commit_success = atomic_compare_exchange_strong_explicit(&q->tail,
- &tail, value, release, release);
- /**
- @Begin
- @Commit_point_define_check: __ATOMIC_RET__ == true
- @Label: Enqueue_Success_Point
- @End
- */
+ /****FIXME: miss ****/
+ // Second release can be just relaxed
+ bool succ = false;
+ succ = atomic_compare_exchange_strong_explicit(&q->tail,
+ &tail, value, release, relaxed);
+ if (succ) {
+ //printf("miss2_enqueue CAS succ\n");
+ }
+ //printf("miss2_enqueue\n");
thrd_yield();
}
}
}
- atomic_compare_exchange_strong_explicit(&q->tail,
+ /**** UL & Inadmissible ****/
+ // Second release can be just relaxed
+ bool succ = atomic_compare_exchange_strong_explicit(&q->tail,
&tail,
MAKE_POINTER(node, get_count(tail) + 1),
- release, release);
+ release, relaxed);
}
-
/**
@Begin
@Interface_define: Dequeue
@End
*/
-unsigned int dequeue(queue_t *q)
+bool dequeue(queue_t *q, int *retVal)
{
- unsigned int value;
+ unsigned int value = 0;
int success = 0;
pointer head;
pointer tail;
pointer next;
while (!success) {
+ /**
+ @Begin
+ @Commit_point_clear: true
+ @Label: Dequeue_Clear
+ @End
+ */
+ /**** Inadmissible ****/
head = atomic_load_explicit(&q->head, acquire);
- tail = atomic_load_explicit(&q->tail, relaxed);
+ /**
+ @Begin
+ @Commit_point_define_check: true
+ @Label: DequeueReadHead
+ @End
+ */
+
+ /** A new bug has been found here!!! It should be acquire instead of
+ * relaxed (it introduces a bug when there's two dequeuers and one
+ * enqueuer) correctness bug!!
+ */
+ /**** New bug ****/
+ tail = atomic_load_explicit(&q->tail, acquire);
+
+ /**** SPEC Error (testcase1.c) ****/
next = atomic_load_explicit(&q->nodes[get_ptr(head)].next, acquire);
+ /**
+ @Begin
+ @Potential_commit_point_define: true
+ @Label: DequeueReadNext
+ @End
+ */
if (atomic_load_explicit(&q->head, relaxed) == head) {
if (get_ptr(head) == get_ptr(tail)) {
/* Check for uninitialized 'next' */
- MODEL_ASSERT(get_ptr(next) != POISON_IDX);
+ //MODEL_ASSERT(get_ptr(next) != POISON_IDX);
- if (get_ptr(next) == 0) { // NULL
- return 0; // NULL
+ if (get_ptr(next) == 0) { // NULL
+ return false; // NULL
}
- atomic_compare_exchange_strong_explicit(&q->tail,
+ /**** FIXME: miss ****/
+ // Second release can be just relaxed
+ bool succ = false;
+ succ = atomic_compare_exchange_strong_explicit(&q->tail,
&tail,
MAKE_POINTER(get_ptr(next), get_count(tail) + 1),
- release, release);
+ release, relaxed);
+ if (succ) {
+ //printf("miss4_dequeue CAS succ\n");
+ }
+ //printf("miss4_dequeue\n");
thrd_yield();
} else {
- value = load_32(&q->nodes[get_ptr(next)].value);
+ //value = load_32(&q->nodes[get_ptr(next)].value);
+ value = q->nodes[get_ptr(next)].value;
+ /**** inadmissibility ****/
success = atomic_compare_exchange_strong_explicit(&q->head,
&head,
MAKE_POINTER(get_ptr(next), get_count(head) + 1),
- release, release);
+ release, relaxed);
+ /**
+ @Begin
+ @Commit_point_define_check: success
+ @Label: DequeueUpdateHead
+ @End
+ */
+
/**
@Begin
- @Commit_point_define_check: __ATOMIC_RET__ == true
- @Label: Dequeue_Success_Point
+ @Commit_point_define: success
+ @Potential_commit_point_label: DequeueReadNext
+ @Label: DequeueReadNextVerify
@End
*/
if (!success)
}
}
reclaim(get_ptr(head));
- return value;
+ *retVal = value;
+ return true;
}
projects / cdsspec-compiler.git / blobdiff