benchmark/ms-queue/my_queue.c

   1 #include <threads.h>
   2 #include <stdlib.h>
   3 #include "librace.h"
   4 #include "model-assert.h"
   5
   6 #include "my_queue.h"
   7
   8 #define relaxed memory_order_relaxed
   9 #define release memory_order_release
  10 #define acquire memory_order_acquire
  11
  12 #define MAX_FREELIST 4 /* Each thread can own up to MAX_FREELIST free nodes */
  13 #define INITIAL_FREE 3 /* Each thread starts with INITIAL_FREE free nodes */
  14
  15 #define POISON_IDX 0x666
  16
  17 static unsigned int (*free_lists)[MAX_FREELIST];
  18
  19 /* Search this thread's free list for a "new" node */
  20 static unsigned int new_node()
  21 {
  22         int i;
  23         int t = get_thread_num();
  24         for (i = 0; i < MAX_FREELIST; i++) {
  25                 //unsigned int node = load_32(&free_lists[t][i]);
  26                 unsigned int node = free_lists[t][i];
  27                 //unsigned int node = free_lists[t][i];
  28                 if (node) {
  29                         //store_32(&free_lists[t][i], 0);
  30                         free_lists[t][i] = 0;
  31                         //free_lists[t][i] = 0;
  32                         return node;
  33                 }
  34         }
  35         /* free_list is empty? */
  36         //MODEL_ASSERT(0);
  37         return 0;
  38 }
  39
  40 /* Place this node index back on this thread's free list */
  41 static void reclaim(unsigned int node)
  42 {
  43         int i;
  44         int t = get_thread_num();
  45
  46         /* Don't reclaim NULL node */
  47         //MODEL_ASSERT(node);
  48
  49         for (i = 0; i < MAX_FREELIST; i++) {
  50                 /* Should never race with our own thread here */
  51                 //unsigned int idx = load_32(&free_lists[t][i]);
  52                 unsigned int idx = free_lists[t][i];
  53                 //unsigned int idx = free_lists[t][i];
  54
  55                 /* Found empty spot in free list */
  56                 if (idx == 0) {
  57                         //store_32(&free_lists[t][i], node);
  58                         free_lists[t][i] = node;
  59                         //free_lists[t][i] = node;
  60                         return;
  61                 }
  62         }
  63         /* free list is full? */
  64         //MODEL_ASSERT(0);
  65 }
  66
  67 void init_queue(queue_t *q, int num_threads)
  68 {
  69         int i, j;
  70
  71         /* Initialize each thread's free list with INITIAL_FREE pointers */
  72         /* The actual nodes are initialized with poison indexes */
  73         free_lists = malloc(num_threads * sizeof(*free_lists));
  74         for (i = 0; i < num_threads; i++) {
  75                 for (j = 0; j < INITIAL_FREE; j++) {
  76                         free_lists[i][j] = 2 + i * MAX_FREELIST + j;
  77                         atomic_init(&q->nodes[free_lists[i][j]].next, MAKE_POINTER(POISON_IDX, 0));
  78                 }
  79         }
  80
  81         /* initialize queue */
  82         atomic_init(&q->head, MAKE_POINTER(1, 0));
  83         atomic_init(&q->tail, MAKE_POINTER(1, 0));
  84         atomic_init(&q->nodes[1].next, MAKE_POINTER(0, 0));
  85 }
  86
  87 /**
  88         @Begin
  89         @Interface_define: Enqueue
  90         @End
  91 */
  92 void enqueue(queue_t *q, unsigned int val)
  93 {
  94         int success = 0;
  95         unsigned int node;
  96         pointer tail;
  97         pointer next;
  98         pointer tmp;
  99
 100         node = new_node();
 101         //store_32(&q->nodes[node].value, val);
 102         q->nodes[node].value = val;
 103         //q->nodes[node].value = val;
 104         tmp = atomic_load_explicit(&q->nodes[node].next, relaxed);
 105         set_ptr(&tmp, 0); // NULL
 106         atomic_store_explicit(&q->nodes[node].next, tmp, relaxed);
 107
 108         while (!success) {
 109                 /**** detected UL (2 threads, 1 enqueue & 1 dequeue)  ****/
 110                 tail = atomic_load_explicit(&q->tail, acquire);
 111                 /****FIXME: miss ****/
 112                 next = atomic_load_explicit(&q->nodes[get_ptr(tail)].next, acquire);
 113                 if (tail == atomic_load_explicit(&q->tail, relaxed)) {
 114
 115                         /* Check for uninitialized 'next' */
 116                         //MODEL_ASSERT(get_ptr(next) != POISON_IDX);
 117
 118                         if (get_ptr(next) == 0) { // == NULL
 119                                 pointer value = MAKE_POINTER(node, get_count(next) + 1);
 120                                 /**** correctness error (1 dequeue & 1 enqueue) ****/
 121                                 success = atomic_compare_exchange_strong_explicit(&q->nodes[get_ptr(tail)].next,
 122                                                 &next, value, release, relaxed);
 123                                 /**
 124                                         @Begin
 125                                         @Commit_point_define_check: success == true
 126                                         @Label: Enqueue_Success_Point
 127                                         @End
 128                                 */
 129                         }
 130                         if (!success) {
 131                                 // This routine helps the other enqueue to update the tail
 132                                 /**** detected UL (2 threads, 1 enqueue & 1 dequeue) ****/
 133                                 unsigned int ptr = get_ptr(atomic_load_explicit(&q->nodes[get_ptr(tail)].next, acquire));
 134                                 pointer value = MAKE_POINTER(ptr,
 135                                                 get_count(tail) + 1);
 136                                 /****FIXME: miss ****/
 137                                 bool succ = false;
 138                                 succ = atomic_compare_exchange_strong_explicit(&q->tail,
 139                                                 &tail, value, release, relaxed);
 140                                 if (succ) {
 141                                         //printf("miss2_enqueue CAS succ\n");
 142                                 }
 143                                 //printf("miss2_enqueue\n");
 144                                 thrd_yield();
 145                         }
 146                 }
 147         }
 148         /**** correctness error (1 dequeue & 1 enqueue) ****/
 149         atomic_compare_exchange_strong_explicit(&q->tail,
 150                         &tail,
 151                         MAKE_POINTER(node, get_count(tail) + 1),
 152                         release, relaxed);
 153 }
 154
 155 /**
 156         @Begin
 157         @Interface_define: Dequeue
 158         @End
 159 */
 160 bool dequeue(queue_t *q, unsigned int *retVal)
 161 {
 162         unsigned int value;
 163         int success = 0;
 164         pointer head;
 165         pointer tail;
 166         pointer next;
 167
 168         while (!success) {
 169                 /**** FIXME: miss ****/
 170                 head = atomic_load_explicit(&q->head, acquire);
 171                 // This must be acquire otherwise we have a bug with 1 enqueue &
 172                 // 1 dequeue
 173                 /**** correctness error (1 dequeue & 1 enqueue) ****/
 174                 tail = atomic_load_explicit(&q->tail, acquire);
 175                 /**** correctness error (1 dequeue & 1 enqueue) ****/
 176                 next = atomic_load_explicit(&q->nodes[get_ptr(head)].next, acquire);
 177                 //printf("miss3_dequeue\n");
 178                 if (atomic_load_explicit(&q->head, relaxed) == head) {
 179                         if (get_ptr(head) == get_ptr(tail)) {
 180
 181                                 /* Check for uninitialized 'next' */
 182                                 //MODEL_ASSERT(get_ptr(next) != POISON_IDX);
 183
 184                                 if (get_ptr(next) == 0) { // NULL
 185                                         /**
 186                                                 @Begin
 187                                                 @Commit_point_define_check: true
 188                                                 @Label: Dequeue_Empty_Point
 189                                                 @End
 190                                         */
 191                                         return false; // NULL
 192                                 }
 193                                 /****FIXME: miss (not reached) ****/
 194                                 bool succ = false;
 195                                 succ = atomic_compare_exchange_strong_explicit(&q->tail,
 196                                                 &tail,
 197                                                 MAKE_POINTER(get_ptr(next), get_count(tail) + 1),
 198                                                 release, relaxed);
 199                                 if (succ) {
 200                                         //printf("miss4_dequeue CAS succ\n");
 201                                 }
 202                                 //printf("miss4_dequeue\n");
 203                                 thrd_yield();
 204                         } else {
 205                                 //*retVal = load_32(&q->nodes[get_ptr(next)].value);
 206                                 *retVal = q->nodes[get_ptr(next)].value;
 207                                 //value = q->nodes[get_ptr(next)].value;
 208                                 /**** FIXME: miss (not reached) ****/
 209                                 success = atomic_compare_exchange_strong_explicit(&q->head,
 210                                                 &head,
 211                                                 MAKE_POINTER(get_ptr(next), get_count(head) + 1),
 212                                                 release, relaxed);
 213                                 /**
 214                                         @Begin
 215                                         @Commit_point_define_check: success == true
 216                                         @Label: Dequeue_Success_Point
 217                                         @End
 218                                 */
 219                                 if (!success)
 220                                         thrd_yield();
 221                         }
 222                 }
 223         }
 224         reclaim(get_ptr(head));
 225         return true;
 226 }