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                 x = atomic_load_explicit(&a->buffer[b % atomic_load_explicit(&a->size,memory_order_relaxed)], memory_order_relaxed);
  39                 /**
  40                         @Begin
  41                         @Commit_point_define_check: t != b
  42                         @Label: Take_Point2
  43                         @End
  44                 */
  45                 if (t == b) {
  46                         /* Single last element in queue. */
  47                         bool succ = atomic_compare_exchange_strong_explicit(&q->top, &t, t +
  48                                 1, memory_order_seq_cst, memory_order_relaxed);
  49                         /**
  50                                 @Begin
  51                                 @Commit_point_define_check: succ == true
  52                                 @Label: Take_Point3
  53                                 @End
  54                         */
  55
  56                         /**
  57                                 @Begin
  58                                 @Commit_point_define_check: succ == false
  59                                 @Label: Take_Point4
  60                                 @End
  61                         */
  62                         if (!succ) {
  63                                 /* Failed race. */
  64                                 x = EMPTY;
  65                         }
  66                         atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
  67                 }
  68         } else { /* Empty queue. */
  69                 x = EMPTY;
  70                 atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
  71         }
  72         return x;
  73 }
  74
  75 void resize(Deque *q) {
  76         Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
  77         size_t size=atomic_load_explicit(&a->size, memory_order_relaxed);
  78         size_t new_size=size << 1;
  79         Array *new_a = (Array *) calloc(1, new_size * sizeof(atomic_int) + sizeof(Array));
  80         size_t top=atomic_load_explicit(&q->top, memory_order_relaxed);
  81         size_t bottom=atomic_load_explicit(&q->bottom, memory_order_relaxed);
  82         atomic_store_explicit(&new_a->size, new_size, memory_order_relaxed);
  83         size_t i;
  84         for(i=top; i < bottom; i++) {
  85                 atomic_store_explicit(&new_a->buffer[i % new_size], atomic_load_explicit(&a->buffer[i % size], memory_order_relaxed), memory_order_relaxed);
  86         }
  87         atomic_store_explicit(&q->array, new_a, memory_order_release);
  88         printf("resize\n");
  89 }
  90
  91 /**
  92         @Begin
  93         @Interface_define: Push
  94         @End
  95 */
  96 void push(Deque *q, int x) {
  97         size_t b = atomic_load_explicit(&q->bottom, memory_order_relaxed);
  98         size_t t = atomic_load_explicit(&q->top, memory_order_acquire);
  99         Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
 100         if (b - t > atomic_load_explicit(&a->size, memory_order_relaxed) - 1) /* Full queue. */ {
 101                 resize(q);
 102                 //Bug in paper...should have next line...
 103                 a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
 104         }
 105         atomic_store_explicit(&a->buffer[b % atomic_load_explicit(&a->size, memory_order_relaxed)], x, memory_order_relaxed);
 106         atomic_thread_fence(memory_order_release);
 107         /**
 108                 @Begin
 109                 @Commit_point_define_check: true
 110                 @Label: Push_Point
 111                 @End
 112         */
 113         atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
 114 }
 115
 116 /**
 117         @Begin
 118         @Interface_define: Steal
 119         @End
 120 */
 121 int steal(Deque *q) {
 122         size_t t = atomic_load_explicit(&q->top, memory_order_acquire);
 123         atomic_thread_fence(memory_order_seq_cst);
 124         size_t b = atomic_load_explicit(&q->bottom, memory_order_acquire);
 125         /**
 126                 @Begin
 127                 @Commit_point_define_check: t >= b
 128                 @Label: Steal_Point1
 129                 @End
 130         */
 131         int x = EMPTY;
 132         if (t < b) {
 133                 /* Non-empty queue. */
 134                 Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_acquire);
 135                 x = atomic_load_explicit(&a->buffer[t % atomic_load_explicit(&a->size, memory_order_relaxed)], memory_order_relaxed);
 136                 bool succ = atomic_compare_exchange_strong_explicit(&q->top, &t, t + 1,
 137                         memory_order_seq_cst, memory_order_relaxed);
 138                 /**
 139                         @Begin
 140                         @Commit_point_define_check: succ == true
 141                         @Label: Steal_Point2
 142                         @End
 143                 */
 144
 145                 /**
 146                         @Begin
 147                         @Commit_point_define_check: succ == false
 148                         @Label: Steal_Point3
 149                         @End
 150                 */
 151                 if (!succ) {
 152                         /* Failed race. */
 153                         return ABORT;
 154                 }
 155         }
 156         return x;
 157 }