benchmark/chase-lev-deque-bugfix/deque.c

   1 #include <stdatomic.h>
   2 #include <inttypes.h>
   3 #include "deque.h"
   4 #include <stdlib.h>
   5 #include <stdio.h>
   6
   7 Deque * create() {
   8         Deque * q = (Deque *) calloc(1, sizeof(Deque));
   9         Array * a = (Array *) calloc(1, sizeof(Array)+2*sizeof(atomic_int));
  10         atomic_store_explicit(&q->array, a, memory_order_relaxed);
  11         atomic_store_explicit(&q->top, 0, memory_order_relaxed);
  12         atomic_store_explicit(&q->bottom, 0, memory_order_relaxed);
  13         atomic_store_explicit(&a->size, 2, memory_order_relaxed);
  14         return q;
  15 }
  16
  17
  18 /**
  19         @Begin
  20         @Interface_define: Take
  21         @End
  22 */
  23 int take(Deque *q) {
  24         size_t b = atomic_load_explicit(&q->bottom, memory_order_relaxed) - 1;
  25         Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
  26         atomic_store_explicit(&q->bottom, b, memory_order_relaxed);
  27         atomic_thread_fence(memory_order_seq_cst);
  28         size_t t = atomic_load_explicit(&q->top, memory_order_relaxed);
  29         /**
  30                 @Begin
  31                 @Commit_point_define_check: t > b
  32                 @Label: Take_Point_1
  33                 @End
  34         */
  35         int x;
  36         if (t <= b) {
  37                 /* Non-empty queue. */
  38                 int size = atomic_load_explicit(&a->size, memory_order_relaxed);
  39                 if (size == 0)
  40                         model_print("take: size == 0\n");
  41                 // TODO: size can be zero here!!
  42                 x = atomic_load_explicit(&a->buffer[b % size], memory_order_relaxed);
  43                 /**
  44                         @Begin
  45                         @Commit_point_define_check: t != b
  46                         @Label: Take_Point2
  47                         @End
  48                 */
  49                 if (t == b) {
  50                         /* Single last element in queue. */
  51                         bool succ = atomic_compare_exchange_strong_explicit(&q->top, &t, t +
  52                                 1, memory_order_seq_cst, memory_order_relaxed);
  53                         /**
  54                                 @Begin
  55                                 @Commit_point_define_check: succ == true
  56                                 @Label: Take_Point3
  57                                 @End
  58                         */
  59
  60                         /**
  61                                 @Begin
  62                                 @Commit_point_define_check: succ == false
  63                                 @Label: Take_Point4
  64                                 @End
  65                         */
  66                         if (!succ) {
  67                                 /* Failed race. */
  68                                 x = EMPTY;
  69                         }
  70                         atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
  71                 }
  72         } else { /* Empty queue. */
  73                 x = EMPTY;
  74                 atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
  75         }
  76         return x;
  77 }
  78
  79 void resize(Deque *q) {
  80         Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
  81         size_t size=atomic_load_explicit(&a->size, memory_order_relaxed);
  82         size_t new_size=size << 1;
  83         Array *new_a = (Array *) calloc(1, new_size * sizeof(atomic_int) + sizeof(Array));
  84         size_t top=atomic_load_explicit(&q->top, memory_order_relaxed);
  85         size_t bottom=atomic_load_explicit(&q->bottom, memory_order_relaxed);
  86         atomic_store_explicit(&new_a->size, new_size, memory_order_relaxed);
  87         size_t i;
  88         for(i=top; i < bottom; i++) {
  89                 if (new_size == 0)
  90                         model_print("resize: new_size == 0\n");
  91                 if (size == 0)
  92                         model_print("resize: size == 0\n");
  93                 atomic_store_explicit(&new_a->buffer[i % new_size], atomic_load_explicit(&a->buffer[i % size], memory_order_relaxed), memory_order_relaxed);
  94         }
  95         atomic_store_explicit(&q->array, new_a, memory_order_release);
  96         printf("resize\n");
  97 }
  98
  99 /**
 100         @Begin
 101         @Interface_define: Push
 102         @End
 103 */
 104 void push(Deque *q, int x) {
 105         size_t b = atomic_load_explicit(&q->bottom, memory_order_relaxed);
 106         size_t t = atomic_load_explicit(&q->top, memory_order_acquire);
 107         Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
 108         if (b - t > atomic_load_explicit(&a->size, memory_order_relaxed) - 1) /* Full queue. */ {
 109                 resize(q);
 110                 //Bug in paper...should have next line...
 111                 a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
 112         }
 113         int size = atomic_load_explicit(&a->size, memory_order_relaxed);
 114         if (size == 0)
 115                 model_print("push: size == 0\n");
 116         atomic_store_explicit(&a->buffer[b % size], x, memory_order_relaxed);
 117         atomic_thread_fence(memory_order_release);
 118         /**
 119                 @Begin
 120                 @Commit_point_define_check: true
 121                 @Label: Push_Point
 122                 @End
 123         */
 124         atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
 125 }
 126
 127 /**
 128         @Begin
 129         @Interface_define: Steal
 130         @End
 131 */
 132 int steal(Deque *q) {
 133         size_t t = atomic_load_explicit(&q->top, memory_order_acquire);
 134         atomic_thread_fence(memory_order_seq_cst);
 135         size_t b = atomic_load_explicit(&q->bottom, memory_order_acquire);
 136         /**
 137                 @Begin
 138                 @Commit_point_define_check: t >= b
 139                 @Label: Steal_Point1
 140                 @End
 141         */
 142         int x = EMPTY;
 143         if (t < b) {
 144                 /* Non-empty queue. */
 145                 Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_acquire);
 146                 int size = atomic_load_explicit(&a->size, memory_order_relaxed);
 147                 if (size == 0)
 148                         model_print("steal: size == 0\n");
 149                 x = atomic_load_explicit(&a->buffer[t % size], memory_order_relaxed);
 150                 bool succ = atomic_compare_exchange_strong_explicit(&q->top, &t, t + 1,
 151                         memory_order_seq_cst, memory_order_relaxed);
 152                 /**
 153                         @Begin
 154                         @Commit_point_define_check: succ == true
 155                         @Label: Steal_Point2
 156                         @End
 157                 */
 158
 159                 /**
 160                         @Begin
 161                         @Commit_point_define_check: succ == false
 162                         @Label: Steal_Point3
 163                         @End
 164                 */
 165                 if (!succ) {
 166                         /* Failed race. */
 167                         return ABORT;
 168                 }
 169         }
 170         return x;
 171 }