X-Git-Url: http://plrg.eecs.uci.edu/git/?p=model-checker-benchmarks.git;a=blobdiff_plain;f=ms-queue%2Fmy_queue.c;h=c63f25497b775ce23332a3b807c84c4fd9b6bd08;hp=eb5d54ad7352f9be434bd9b76b06063963d81727;hb=fad3891f3158a4285984bb60415c1e4ebc2b767b;hpb=bead5206c1935e3b499300c7e8b5b41a259a04c6

diff --git a/ms-queue/my_queue.c b/ms-queue/my_queue.c
index eb5d54a..c63f254 100644
--- a/ms-queue/my_queue.c
+++ b/ms-queue/my_queue.c
@@ -1,50 +1,56 @@
 #include <threads.h>
+#include <stdlib.h>
+#include "librace.h"
 
 #include "my_queue.h"
 
-extern private_t private;
+#define relaxed memory_order_relaxed
+#define release memory_order_release
+#define acquire memory_order_acquire
 
-void init_private(int pid)
-{
-	private.node = 2 + pid;
-}
+static unsigned int *node_nums;
 
 static unsigned int new_node()
 {
-	return private.node;
+	return node_nums[get_thread_num()];
 }
 
 static void reclaim(unsigned int node)
 {
-	private.node = node;
+	node_nums[get_thread_num()] = node;
 }
 
-void init_queue(queue_t *q)
+void init_queue(queue_t *q, int num_threads)
 {
 	unsigned int i;
 	pointer head;
 	pointer tail;
 	pointer next;
 
+	node_nums = malloc(num_threads * sizeof(*node_nums));
+	for (i = 0; i < num_threads; i++)
+		node_nums[i] = 2 + i;
+
+	/* Note: needed to add this init manually */
+	atomic_init(&q->nodes[0].next, 0);
+
 	/* initialize queue */
 	head = MAKE_POINTER(1, 0);
 	tail = MAKE_POINTER(1, 0);
 	next = MAKE_POINTER(0, 0); // (NULL, 0)
 
-	atomic_init(&q->nodes[0].next, 0); // assumed inititalized in original example
-
-	atomic_store(&q->head, head);
-	atomic_store(&q->tail, tail);
-	atomic_store(&q->nodes[1].next, next);
+	atomic_init(&q->head, head);
+	atomic_init(&q->tail, tail);
+	atomic_init(&q->nodes[1].next, next);
 
 	/* initialize avail list */
 	for (i = 2; i < MAX_NODES; i++) {
 		next = MAKE_POINTER(i + 1, 0);
-		atomic_store(&q->nodes[i].next, next);
+		atomic_init(&q->nodes[i].next, next);
 	}
 
 	next = MAKE_POINTER(0, 0); // (NULL, 0)
-	atomic_store(&q->nodes[MAX_NODES].next, next);
+	atomic_init(&q->nodes[MAX_NODES].next, next);
 }
 
 void enqueue(queue_t *q, unsigned int val)
@@ -55,36 +61,38 @@ void enqueue(queue_t *q, unsigned int val)
 	pointer next;
 	pointer tmp;
 
+	/* Get a fresh node, set its value field, then set it's next reference to null */
 	node = new_node();
-	q->nodes[node].value = val;
-	tmp = atomic_load(&q->nodes[node].next);
+	store_32(&q->nodes[node].value, val);
+	tmp = atomic_load_explicit(&q->nodes[node].next, relaxed);
 	set_ptr(&tmp, 0); // NULL
-	atomic_store(&q->nodes[node].next, tmp);
+	atomic_store_explicit(&q->nodes[node].next, tmp, relaxed);
 
 	while (!success) {
-		tail = atomic_load(&q->tail);
-		next = atomic_load(&q->nodes[get_ptr(tail)].next);
-		if (tail == atomic_load(&q->tail)) {
+		//tail isn't actually synchronization point
+		tail = atomic_load_explicit(&q->tail, relaxed);
+		//acquire reference
+		next = atomic_load_explicit(&q->nodes[get_ptr(tail)].next, relaxed);
+		if (tail == atomic_load_explicit(&q->tail, relaxed)) {
 			if (get_ptr(next) == 0) { // == NULL
-				pointer val = MAKE_POINTER(node, get_count(next) + 1);
-				success = atomic_compare_exchange_weak(&q->nodes[get_ptr(tail)].next,
-						&next,
-						val);
+				pointer value = MAKE_POINTER(node, get_count(next) + 1);
+				success = atomic_compare_exchange_strong_explicit(&q->nodes[get_ptr(tail)].next,
+						&next, value, memory_order_release, memory_order_release);
 			}
 			if (!success) {
-				unsigned int ptr = get_ptr(atomic_load(&q->nodes[get_ptr(tail)].next));
-				pointer val = MAKE_POINTER(ptr,
+				unsigned int ptr = get_ptr(atomic_load_explicit(&q->nodes[get_ptr(tail)].next, memory_order_relaxed));
+				pointer value = MAKE_POINTER(ptr,
 						get_count(tail) + 1);
-				atomic_compare_exchange_strong(&q->tail,
-						&tail,
-						val);
-				thrd_yield();
+				atomic_compare_exchange_strong_explicit(&q->tail,
+						&tail, value,
+						memory_order_relaxed, memory_order_relaxed);
 			}
 		}
 	}
-	atomic_compare_exchange_strong(&q->tail,
+	atomic_compare_exchange_strong_explicit(&q->tail,
 			&tail,
-			MAKE_POINTER(node, get_count(tail) + 1));
+			MAKE_POINTER(node, get_count(tail) + 1),
+			memory_order_relaxed, memory_order_relaxed);
 }
 
 unsigned int dequeue(queue_t *q)
@@ -96,25 +104,24 @@ unsigned int dequeue(queue_t *q)
 	pointer next;
 
 	while (!success) {
-		head = atomic_load(&q->head);
-		tail = atomic_load(&q->tail);
-		next = atomic_load(&q->nodes[get_ptr(head)].next);
-		if (atomic_load(&q->head) == head) {
+		head = atomic_load_explicit(&q->head, relaxed);
+		tail = atomic_load_explicit(&q->tail, relaxed);
+		next = atomic_load_explicit(&q->nodes[get_ptr(head)].next, acquire);
+		if (atomic_load_explicit(&q->head, relaxed) == head) {
 			if (get_ptr(head) == get_ptr(tail)) {
 				if (get_ptr(next) == 0) { // NULL
 					return 0; // NULL
 				}
-				atomic_compare_exchange_weak(&q->tail,
+				atomic_compare_exchange_strong_explicit(&q->tail,
 						&tail,
-						MAKE_POINTER(get_ptr(next), get_count(tail) + 1));
-				thrd_yield();
+						MAKE_POINTER(get_ptr(next), get_count(tail) + 1),
+						memory_order_relaxed, memory_order_relaxed);
 			} else {
-				value = q->nodes[get_ptr(next)].value;
-				success = atomic_compare_exchange_weak(&q->head,
+				value = load_32(&q->nodes[get_ptr(next)].value);
+				success = atomic_compare_exchange_strong_explicit(&q->head,
 						&head,
-						MAKE_POINTER(get_ptr(next), get_count(head) + 1));
-				if (!success)
-					thrd_yield();
+						MAKE_POINTER(get_ptr(next), get_count(head) + 1),
+						memory_order_relaxed, memory_order_relaxed);
 			}
 		}
 	}