ms-queue: fixups, add simple race detection

[model-checker-benchmarks.git] / ms-queue / my_queue.c

diff --git a/ms-queue/my_queue.c b/ms-queue/my_queue.c
index 1f8a4461e87e7688d1ca73c32b2b4503b1b0955b..67ec68090545aa2eabf2114dc1bfeed880d74d6d 100644 (file)
--- a/ms-queue/my_queue.c
+++ b/ms-queue/my_queue.c
@@ -1,130 +1,120 @@
-#include "main.h"
+#include <threads.h>
+#include <stdlib.h>
+#include "librace.h"
 
-extern unsigned pid;
-extern unsigned iterations;
-extern unsigned initial_nodes;
-extern private_t private;
-extern shared_mem_t* smp;
+#include "my_queue.h"
 
-void init_private()
-{
-       private.node = 2 + initial_nodes + pid;
-       private.value = 1 + initial_nodes + (pid * iterations);
-
-}
+static unsigned int *node_nums;
 
-void init_memory()
+static unsigned int new_node()
 {
+       return node_nums[get_thread_num()];
 }
 
-static unsigned new_node()
+static void reclaim(unsigned int node)
 {
-       return private.node;
+       node_nums[get_thread_num()] = node;
 }
 
-static void reclaim(unsigned node)
+void init_queue(queue_t *q, int num_threads)
 {
-       private.node = node;
-}
+       unsigned int i;
+       pointer head;
+       pointer tail;
+       pointer next;
 
-void init_queue()
-{
-       unsigned i;
+       node_nums = malloc(num_threads * sizeof(*node_nums));
+       for (i = 0; i < num_threads; i++)
+               node_nums[i] = 2 + i;
 
        /* initialize queue */
-       smp->head.sep.ptr = 1;
-       smp->head.sep.count = 0;
-       smp->tail.sep.ptr = 1;
-       smp->tail.sep.count = 0;
-       smp->nodes[1].next.sep.ptr = NULL;
-       smp->nodes[1].next.sep.count = 0;
+       head = MAKE_POINTER(1, 0);
+       tail = MAKE_POINTER(1, 0);
+       next = MAKE_POINTER(0, 0); // (NULL, 0)
+
+       atomic_store(&q->head, head);
+       atomic_store(&q->tail, tail);
+       atomic_store(&q->nodes[1].next, next);
 
        /* initialize avail list */
-       for (i=2; i<MAX_NODES; i++) {
-               smp->nodes[i].next.sep.ptr = i+1;
-               smp->nodes[i].next.sep.count = 0;
+       for (i = 2; i < MAX_NODES; i++) {
+               next = MAKE_POINTER(i + 1, 0);
+               atomic_store(&q->nodes[i].next, next);
        }
-       smp->nodes[MAX_NODES].next.sep.ptr = NULL;
-       smp->nodes[MAX_NODES].next.sep.count = 0;
 
-       /* initialize queue contents */
-       if (initial_nodes > 0) {
-               for (i=2; i<initial_nodes+2; i++) {
-                       smp->nodes[i].value = i;
-                       smp->nodes[i-1].next.sep.ptr = i;
-                       smp->nodes[i].next.sep.ptr = NULL;
-               }
-               smp->head.sep.ptr = 1;
-               smp->tail.sep.ptr = 1 + initial_nodes;    
-       }
+       next = MAKE_POINTER(0, 0); // (NULL, 0)
+       atomic_store(&q->nodes[MAX_NODES].next, next);
 }
 
-void enqueue(unsigned val)
+void enqueue(queue_t *q, unsigned int val)
 {
-       unsigned success;
-       unsigned node;
-       pointer_t tail;
-       pointer_t next;
+       int success = 0;
+       unsigned int node;
+       pointer tail;
+       pointer next;
+       pointer tmp;
 
        node = new_node();
-       smp->nodes[node].value = val;
-       smp->nodes[node].next.sep.ptr = NULL;
+       store_32(&q->nodes[node].value, val);
+       tmp = atomic_load(&q->nodes[node].next);
+       set_ptr(&tmp, 0); // NULL
+       atomic_store(&q->nodes[node].next, tmp);
 
-       for (success = FALSE; success == FALSE; ) {
-               tail.con = smp->tail.con;
-               next.con = smp->nodes[tail.sep.ptr].next.con;
-               if (tail.con == smp->tail.con) {
-                       if (next.sep.ptr == NULL) {
-                               success = cas(&smp->nodes[tail.sep.ptr].next, 
-                                               next.con,
-                                               MAKE_LONG(node, next.sep.count+1));
+       while (!success) {
+               tail = atomic_load(&q->tail);
+               next = atomic_load(&q->nodes[get_ptr(tail)].next);
+               if (tail == atomic_load(&q->tail)) {
+                       if (get_ptr(next) == 0) { // == NULL
+                               pointer value = MAKE_POINTER(node, get_count(next) + 1);
+                               success = atomic_compare_exchange_weak(&q->nodes[get_ptr(tail)].next,
+                                               &next, value);
                        }
-                       if (success == FALSE) {
-                               cas(&smp->tail,
-                                               tail.con,
-                                               MAKE_LONG(smp->nodes[tail.sep.ptr].next.sep.ptr,
-                                                       tail.sep.count+1));
+                       if (!success) {
+                               unsigned int ptr = get_ptr(atomic_load(&q->nodes[get_ptr(tail)].next));
+                               pointer value = MAKE_POINTER(ptr,
+                                               get_count(tail) + 1);
+                               atomic_compare_exchange_strong(&q->tail,
+                                               &tail, value);
                                thrd_yield();
                        }
                }
        }
-       cas(&smp->tail, 
-                       tail.con,
-                       MAKE_LONG(node, tail.sep.count+1));
+       atomic_compare_exchange_strong(&q->tail,
+                       &tail,
+                       MAKE_POINTER(node, get_count(tail) + 1));
 }
 
-unsigned dequeue()
+unsigned int dequeue(queue_t *q)
 {
-       unsigned value;
-       unsigned success;
-       pointer_t head;
-       pointer_t tail;
-       pointer_t next;
+       unsigned int value;
+       int success = 0;
+       pointer head;
+       pointer tail;
+       pointer next;
 
-       for (success = FALSE; success == FALSE; ) {
-               head.con = smp->head.con;
-               tail.con = smp->tail.con;
-               next.con = smp->nodes[head.sep.ptr].next.con;
-               if (smp->head.con == head.con) {
-                       if (head.sep.ptr == tail.sep.ptr) {
-                               if (next.sep.ptr == NULL) {
-                                       return NULL;
+       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) {
+                       if (get_ptr(head) == get_ptr(tail)) {
+                               if (get_ptr(next) == 0) { // NULL
+                                       return 0; // NULL
                                }
-                               cas(&smp->tail,
-                                               tail.con,
-                                               MAKE_LONG(next.sep.ptr, tail.sep.count+1));
+                               atomic_compare_exchange_strong(&q->tail,
+                                               &tail,
+                                               MAKE_POINTER(get_ptr(next), get_count(tail) + 1));
                                thrd_yield();
                        } else {
-                               value = smp->nodes[next.sep.ptr].value;
-                               success = cas(&smp->head,
-                                               head.con,
-                                               MAKE_LONG(next.sep.ptr, head.sep.count+1));
-                               if (success == FALSE) {
+                               value = load_32(&q->nodes[get_ptr(next)].value);
+                               success = atomic_compare_exchange_weak(&q->head,
+                                               &head,
+                                               MAKE_POINTER(get_ptr(next), get_count(head) + 1));
+                               if (!success)
                                        thrd_yield();
-                               }
                        }
                }
        }
-       reclaim(head.sep.ptr);
+       reclaim(get_ptr(head));
        return value;
 }