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                         bool succ = atomic_compare_exchange_strong_explicit(&q->top, &t, t +
  49                                 1, memory_order_seq_cst, memory_order_relaxed);
  50                         /**
  51                                 @Begin
  52                                 @Commit_point_define_check: succ
  53                                 @Label: Take_Point3
  54                                 @End
  55                         */
  56                         if (!succ) {
  57                                 /* Failed race. */
  58                                 x = EMPTY;
  59                         }
  60                         atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
  61                 }
  62         } else { /* Empty queue. */
  63                 x = EMPTY;
  64                 atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
  65         }
  66         return x;
  67 }
  68
  69 void resize(Deque *q) {
  70         Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
  71         size_t size=atomic_load_explicit(&a->size, memory_order_relaxed);
  72         size_t new_size=size << 1;
  73         Array *new_a = (Array *) calloc(1, new_size * sizeof(atomic_int) + sizeof(Array));
  74         size_t top=atomic_load_explicit(&q->top, memory_order_relaxed);
  75         size_t bottom=atomic_load_explicit(&q->bottom, memory_order_relaxed);
  76         atomic_store_explicit(&new_a->size, new_size, memory_order_relaxed);
  77         size_t i;
  78         for(i=top; i < bottom; i++) {
  79                 atomic_store_explicit(&new_a->buffer[i % new_size], atomic_load_explicit(&a->buffer[i % size], memory_order_relaxed), memory_order_relaxed);
  80         }
  81         atomic_store_explicit(&q->array, new_a, memory_order_release);
  82         printf("resize\n");
  83 }
  84
  85 /**
  86         @Begin
  87         @Interface_define: Push
  88         @End
  89 */
  90 void push(Deque *q, int x) {
  91         size_t b = atomic_load_explicit(&q->bottom, memory_order_relaxed);
  92         size_t t = atomic_load_explicit(&q->top, memory_order_acquire);
  93         Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
  94         if (b - t > atomic_load_explicit(&a->size, memory_order_relaxed) - 1) /* Full queue. */ {
  95                 resize(q);
  96                 //Bug in paper...should have next line...
  97                 a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
  98         }
  99         int size = atomic_load_explicit(&a->size, memory_order_relaxed);
 100         atomic_store_explicit(&a->buffer[b % size], x, memory_order_relaxed);
 101         /**
 102                 @Begin
 103                 @Commit_point_define_check: true
 104                 @Label: Push_Point
 105                 @End
 106         */
 107         atomic_thread_fence(memory_order_release);
 108
 109         atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
 110
 111 }
 112
 113 /**
 114         @Begin
 115         @Interface_define: Steal
 116         @End
 117 */
 118 int steal(Deque *q) {
 119         size_t t = atomic_load_explicit(&q->top, memory_order_acquire);
 120         atomic_thread_fence(memory_order_seq_cst);
 121         size_t b = atomic_load_explicit(&q->bottom, memory_order_acquire);
 122         /**
 123                 @Begin
 124                 @Commit_point_define_check: t >= b
 125                 @Label: Steal_Point1
 126                 @End
 127         */
 128         int x = EMPTY;
 129         if (t < b) {
 130                 /* Non-empty queue. */
 131                 Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_acquire);
 132                 int size = atomic_load_explicit(&a->size, memory_order_relaxed);
 133                 x = atomic_load_explicit(&a->buffer[t % size], memory_order_relaxed);
 134                 /**
 135                         @Begin
 136                         @Potential_commit_point_define: true
 137                         @Label: Potential_Steal
 138                         @End
 139                 */
 140
 141                 bool succ = atomic_compare_exchange_strong_explicit(&q->top, &t, t + 1,
 142                         memory_order_seq_cst, memory_order_relaxed);
 143                 /**
 144                         @Begin
 145                         @Commit_point_define_check: !succ
 146                         @Label: Steal_Point4
 147                         @End
 148                 */
 149
 150                 /**
 151                         @Begin
 152                         @Commit_point_define: succ
 153                         @Potential_commit_point_label: Potential_Steal
 154                         @Label: Steal_Point3
 155                         @End
 156                 */
 157                 if (!succ) {
 158                         /* Failed race. */
 159                         return ABORT;
 160                 }
 161         }
 162         return x;
 163 }