| @@ -0,0 +1,75 @@ |
| 1 | +#include <stddef.h> |
| 2 | +#include <stdint.h> |
| 3 | +#include <stdlib.h> |
| 4 | +#include <stdio.h> |
| 5 | +#include <pthread.h> |
| 6 | +#include <stdatomic.h> |
| 7 | + |
| 8 | +#define NR_THREADS 16 |
| 9 | +#define NR_STEPS ((uint32_t)UINT16_MAX * 4) |
| 10 | + |
| 11 | +#define BUG_ON(COND) \ |
| 12 | + do { \ |
| 13 | + if (!!(COND)) \ |
| 14 | + abort(); \ |
| 15 | + } while (0) |
| 16 | + |
| 17 | +static |
| 18 | +void *adder_simple(void *arg) |
| 19 | +{ |
| 20 | + size_t step; |
| 21 | + atomic_size_t *counter = arg; |
| 22 | + |
| 23 | + for (step = 0; step < NR_STEPS; ++step) |
| 24 | + atomic_fetch_add_explicit(counter, 1, memory_order_relaxed); |
| 25 | + |
| 26 | + return NULL; |
| 27 | +} |
| 28 | + |
| 29 | +static |
| 30 | +void *adder_cmpxchg(void *arg) |
| 31 | +{ |
| 32 | + size_t step; |
| 33 | + atomic_size_t *counter = arg; |
| 34 | + |
| 35 | + for (step = 0; step < NR_STEPS; ++step) { |
| 36 | + size_t xchg; |
| 37 | + size_t cmp = atomic_load_explicit(counter, memory_order_relaxed); |
| 38 | + |
| 39 | + do { |
| 40 | + xchg = (cmp + 1); |
| 41 | + } while (!atomic_compare_exchange_strong_explicit(counter, |
| 42 | + &cmp, xchg, memory_order_relaxed, memory_order_relaxed)); |
| 43 | + } |
| 44 | + |
| 45 | + return NULL; |
| 46 | +} |
| 47 | + |
| 48 | +static |
| 49 | +void atomic_counter_test(void *(*adder)(void *arg)) |
| 50 | +{ |
| 51 | + size_t index; |
| 52 | + atomic_size_t counter; |
| 53 | + pthread_t thread[NR_THREADS]; |
| 54 | + |
| 55 | + atomic_init(&counter, 0); |
| 56 | + |
| 57 | + for (index = 0; index < NR_THREADS; ++index) |
| 58 | + BUG_ON(pthread_create(&thread[index], NULL, adder, (void *)&counter)); |
| 59 | + |
| 60 | + for (index = 0; index < NR_THREADS; ++index) |
| 61 | + BUG_ON(pthread_join(thread[index], NULL)); |
| 62 | + |
| 63 | + if (atomic_load(&counter) == (NR_THREADS * NR_STEPS)) |
| 64 | + printf("SUCCESS\n"); |
| 65 | + else |
| 66 | + printf("FAILURE\n"); |
| 67 | +} |
| 68 | + |
| 69 | +int main(void) |
| 70 | +{ |
| 71 | + atomic_counter_test(adder_simple); |
| 72 | + atomic_counter_test(adder_cmpxchg); |
| 73 | + |
| 74 | + return 0; |
| 75 | +} |