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         atomic_store_explicit(&q->array, new_a, memory_order_release);
  83         printf("resize\n");
  84 }
  85
  86 /**
  87         @Begin
  88         @Interface_define: Push
  89         @End
  90 */
  91 void push(Deque *q, int x) {
  92         size_t b = atomic_load_explicit(&q->bottom, memory_order_relaxed);
  93         size_t t = atomic_load_explicit(&q->top, memory_order_acquire);
  94         Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
  95         if (b - t > atomic_load_explicit(&a->size, memory_order_relaxed) - 1) /* Full queue. */ {
  96                 resize(q);
  97                 //Bug in paper...should have next line...
  98                 a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
  99         }
 100         int size = atomic_load_explicit(&a->size, memory_order_relaxed);
 101         atomic_store_explicit(&a->buffer[b % size], x, memory_order_relaxed);
 102         /**
 103                 @Begin
 104                 @Commit_point_define_check: true
 105                 @Label: Push_Point
 106                 @End
 107         */
 108         atomic_thread_fence(memory_order_release);
 109
 110         atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
 111
 112 }
 113
 114 /**
 115         @Begin
 116         @Interface_define: Steal
 117         @End
 118 */
 119 int steal(Deque *q) {
 120         //FIXME: weaken the following acquire causes no spec problem
 121         size_t t = atomic_load_explicit(&q->top, memory_order_acquire);
 122         atomic_thread_fence(memory_order_seq_cst);
 123         size_t b = atomic_load_explicit(&q->bottom, memory_order_acquire);
 124         /**
 125                 @Begin
 126                 @Commit_point_define_check: t >= b
 127                 @Label: Steal_Point1
 128                 @End
 129         */
 130         int x = EMPTY;
 131         if (t < b) {
 132                 /* Non-empty queue. */
 133                 Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_acquire);
 134                 int size = atomic_load_explicit(&a->size, memory_order_relaxed);
 135                 x = atomic_load_explicit(&a->buffer[t % size], memory_order_relaxed);
 136                 /**
 137                         @Begin
 138                         @Potential_commit_point_define: true
 139                         @Label: Potential_Steal
 140                         @End
 141                 */
 142
 143                 bool succ = atomic_compare_exchange_strong_explicit(&q->top, &t, t + 1,
 144                         memory_order_seq_cst, memory_order_relaxed);
 145                 /**
 146                         @Begin
 147                         @Commit_point_define_check: !succ
 148                         @Label: Steal_Point2
 149                         @End
 150                 */
 151
 152                 /**
 153                         @Begin
 154                         @Commit_point_define: succ
 155                         @Potential_commit_point_label: Potential_Steal
 156                         @Label: Steal_Point3
 157                         @End
 158                 */
 159                 if (!succ) {
 160                         /* Failed race. */
 161                         return ABORT;
 162                 }
 163         }
 164         return x;
 165 }