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                 x = atomic_load_explicit(&a->buffer[b % size], memory_order_relaxed);
  40                 /**
  41                         @Begin
  42                         @Commit_point_define_check: t != b
  43                         @Label: Take_Point2
  44                         @End
  45                 */
  46                 if (t == b) {
  47                         /* Single last element in queue. */
  48                         //FIXME: weaken the following seq_cst causes no spec problem
  49                         bool succ = atomic_compare_exchange_strong_explicit(&q->top, &t, t +
  50                                 1, memory_order_seq_cst, memory_order_relaxed);
  51                         /**
  52                                 @Begin
  53                                 @Commit_point_define_check: true
  54                                 @Label: Take_Point3
  55                                 @End
  56                         */
  57                         if (!succ) {
  58                                 /* Failed race. */
  59                                 x = EMPTY;
  60                         }
  61                         atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
  62                 }
  63         } else { /* Empty queue. */
  64                 x = EMPTY;
  65                 atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
  66         }
  67         return x;
  68 }
  69
  70 void resize(Deque *q) {
  71         Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
  72         size_t size=atomic_load_explicit(&a->size, memory_order_relaxed);
  73         size_t new_size=size << 1;
  74         Array *new_a = (Array *) calloc(1, new_size * sizeof(atomic_int) + sizeof(Array));
  75         size_t top=atomic_load_explicit(&q->top, memory_order_relaxed);
  76         size_t bottom=atomic_load_explicit(&q->bottom, memory_order_relaxed);
  77         atomic_store_explicit(&new_a->size, new_size, memory_order_relaxed);
  78         size_t i;
  79         for(i=top; i < bottom; i++) {
  80                 atomic_store_explicit(&new_a->buffer[i % new_size], atomic_load_explicit(&a->buffer[i % size], memory_order_relaxed), memory_order_relaxed);
  81         }
  82         /**** FIXME: detected failure ****/
  83         atomic_store_explicit(&q->array, new_a, memory_order_release);
  84         printf("resize\n");
  85 }
  86
  87 /**
  88         @Begin
  89         @Interface_define: Push
  90         @End
  91 */
  92 void push(Deque *q, int x) {
  93         size_t b = atomic_load_explicit(&q->bottom, memory_order_relaxed);
  94         /**** FIXME: detected correctness ****/
  95         size_t t = atomic_load_explicit(&q->top, memory_order_acquire);
  96         Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
  97         if (b - t > atomic_load_explicit(&a->size, memory_order_relaxed) - 1) /* Full queue. */ {
  98                 resize(q);
  99                 //Bug in paper...should have next line...
 100                 a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
 101         }
 102         int size = atomic_load_explicit(&a->size, memory_order_relaxed);
 103         atomic_store_explicit(&a->buffer[b % size], x, memory_order_relaxed);
 104         /**
 105                 @Begin
 106                 @Commit_point_define_check: true
 107                 @Label: Push_Point
 108                 @End
 109         */
 110         atomic_thread_fence(memory_order_release);
 111
 112         atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
 113
 114 }
 115
 116 /**
 117         @Begin
 118         @Interface_define: Steal
 119         @End
 120 */
 121 int steal(Deque *q) {
 122         //FIXME: weaken the following acquire causes no spec problem
 123         size_t t = atomic_load_explicit(&q->top, memory_order_acquire);
 124         atomic_thread_fence(memory_order_seq_cst);
 125         size_t b = atomic_load_explicit(&q->bottom, memory_order_acquire);
 126         /**
 127                 @Begin
 128                 @Commit_point_define_check: t >= b
 129                 @Label: Steal_Point1
 130                 @End
 131         */
 132         int x = EMPTY;
 133         if (t < b) {
 134                 /* Non-empty queue. */
 135                 Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_acquire);
 136                 int size = atomic_load_explicit(&a->size, memory_order_relaxed);
 137                 x = atomic_load_explicit(&a->buffer[t % size], memory_order_relaxed);
 138                 /**
 139                         @Begin
 140                         @Potential_commit_point_define: true
 141                         @Label: Potential_Steal
 142                         @End
 143                 */
 144
 145                 bool succ = atomic_compare_exchange_strong_explicit(&q->top, &t, t + 1,
 146                         memory_order_seq_cst, memory_order_relaxed);
 147                 /**
 148                         @Begin
 149                         @Commit_point_define_check: !succ
 150                         @Label: Steal_Point2
 151                         @End
 152                 */
 153
 154                 /**
 155                         @Begin
 156                         @Commit_point_define: succ
 157                         @Potential_commit_point_label: Potential_Steal
 158                         @Label: Steal_Point3
 159                         @End
 160                 */
 161                 if (!succ) {
 162                         /* Failed race. */
 163                         return ABORT;
 164                 }
 165         }
 166         return x;
 167 }