#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
}
}
/* 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 */
}
}
/* free list is full? */
- MODEL_ASSERT(0);
+ //MODEL_ASSERT(0);
}
void init_queue(queue_t *q, int num_threads)
{
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 */
atomic_store_explicit(&q->nodes[node].next, tmp, relaxed);
while (!success) {
- /****FIXME: detected UL ****/
+
+ /**
+ @Begin
+ @Commit_point_clear: true
+ @Label: Enqueue_Clear
+ @End
+ */
+ /**** detected UL ****/
tail = atomic_load_explicit(&q->tail, acquire);
/****FIXME: miss ****/
next = atomic_load_explicit(&q->nodes[get_ptr(tail)].next, acquire);
- printf("miss1_enqueue\n");
+ //printf("miss1_enqueue\n");
if (tail == atomic_load_explicit(&q->tail, relaxed)) {
/* Check for uninitialized 'next' */
if (get_ptr(next) == 0) { // == NULL
pointer value = MAKE_POINTER(node, get_count(next) + 1);
- /****FIXME: first release UL ****/
+ /**** detected UL ****/
// Second release can be just relaxed
success = atomic_compare_exchange_strong_explicit(&q->nodes[get_ptr(tail)].next,
&next, value, release, relaxed);
/**
@Begin
- @Commit_point_define_check: success == true
- @Label: Enqueue_Success_Point
+ @Commit_point_define_check: success
+ @Label: EnqueueUpdateNext
@End
*/
}
if (!success) {
- /****FIXME: detected UL ****/
+ // This routine helps the other enqueue to update the tail
+ /**** detected UL ****/
unsigned int ptr = get_ptr(atomic_load_explicit(&q->nodes[get_ptr(tail)].next, acquire));
pointer value = MAKE_POINTER(ptr,
get_count(tail) + 1);
/****FIXME: miss ****/
- // Seconde release can be just relaxed
- atomic_compare_exchange_strong_explicit(&q->tail,
+ // Second release can be just relaxed
+ bool succ = false;
+ succ = atomic_compare_exchange_strong_explicit(&q->tail,
&tail, value, release, relaxed);
- printf("miss2_enqueue\n");
+ if (succ) {
+ //printf("miss2_enqueue CAS succ\n");
+ }
+ //printf("miss2_enqueue\n");
thrd_yield();
}
}
}
- /****FIXME: first UL ****/
- // Seconde release can be just relaxed
- atomic_compare_exchange_strong_explicit(&q->tail,
+ /**** dectected UL ****/
+ // Second release can be just relaxed
+ bool succ = atomic_compare_exchange_strong_explicit(&q->tail,
&tail,
MAKE_POINTER(node, get_count(tail) + 1),
release, relaxed);
@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) {
- /****FIXME: detected correctness error ****/
+ /**
+ @Begin
+ @Commit_point_clear: true
+ @Label: Dequeue_Clear
+ @End
+ */
+ /**** detected correctness error ****/
head = atomic_load_explicit(&q->head, acquire);
- tail = atomic_load_explicit(&q->tail, relaxed);
- /****FIXME: miss ****/
+ /** 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!!
+ */
+ tail = atomic_load_explicit(&q->tail, acquire);
+
+ /**** Detected UL/DR (testcase1.c) ****/
next = atomic_load_explicit(&q->nodes[get_ptr(head)].next, acquire);
- printf("miss3_dequeue\n");
+ /**
+ @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);
-
- if (get_ptr(next) == 0) { // NULL
- /**
- @Begin
- @Commit_point_define_check: true
- @Label: Dequeue_Empty_Point
- @End
- */
- return 0; // NULL
+ //MODEL_ASSERT(get_ptr(next) != POISON_IDX);
+
+ if (get_ptr(next) == 0) { // NULL
+ return false; // NULL
}
- /****FIXME: miss (not reached) ****/
- // Seconde release can be just relaxed
- atomic_compare_exchange_strong_explicit(&q->tail,
+ /**** Detected UL (testcase1.c) ****/
+ // 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, relaxed);
- printf("miss4_dequeue\n");
+ 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 = q->nodes[get_ptr(next)].value;
- /****FIXME: correctness error ****/
- // Seconde release can be just relaxed
+ /**** correctness error ****/
success = atomic_compare_exchange_strong_explicit(&q->head,
&head,
MAKE_POINTER(get_ptr(next), get_count(head) + 1),
release, relaxed);
/**
@Begin
- @Commit_point_define_check: success == true
- @Label: Dequeue_Success_Point
+ @Commit_point_define_check: success
+ @Label: DequeueUpdateHead
+ @End
+ */
+
+ /**
+ @Begin
+ @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