mop.cpp revision 360784 
1// Synthetic benchmark for __tsan_read/write{1,2,4,8}.
2// As compared to mini_bench_local/shared.cc this benchmark passes through
3// deduplication logic (ContainsSameAccess).
4// First argument is access size (1, 2, 4, 8). Second optional arg switches
5// from writes to reads.
6
7#include <pthread.h>
8#include <stdlib.h>
9#include <stdio.h>
10#include <unistd.h>
11#include <linux/futex.h>
12#include <sys/syscall.h>
13#include <sys/time.h>
14
15template<typename T, bool write>
16void* thread(void *arg) {
17  const int kSize = 2 << 10;
18  static volatile long data[kSize];
19  static volatile long turn;
20  const int kRepeat = 1 << 17;
21  const int id = !!arg;
22  for (int i = 0; i < kRepeat; i++) {
23    for (;;) {
24      int t = __atomic_load_n(&turn, __ATOMIC_ACQUIRE);
25      if (t == id)
26        break;
27      syscall(SYS_futex, &turn, FUTEX_WAIT, t, 0, 0, 0);
28    }
29    for (int j = 0; j < kSize; j++) {
30      if (write) {
31        ((volatile T*)&data[j])[0] = 1;
32        ((volatile T*)&data[j])[sizeof(T) == 8 ? 0 : 1] = 1;
33      } else {
34        T v0 = ((volatile T*)&data[j])[0];
35        T v1 = ((volatile T*)&data[j])[sizeof(T) == 8 ? 0 : 1];
36        (void)v0;
37        (void)v1;
38      }
39    }
40    __atomic_store_n(&turn, 1 - id, __ATOMIC_RELEASE);
41    syscall(SYS_futex, &turn, FUTEX_WAKE, 0, 0, 0, 0);
42  }
43  return 0;
44}
45
46template<typename T, bool write>
47void test() {
48  pthread_t th;
49  pthread_create(&th, 0, thread<T, write>, (void*)1);
50  thread<T, write>(0);
51  pthread_join(th, 0);
52}
53
54template<bool write>
55void testw(int size) {
56  switch (size) {
57  case 1: return test<char, write>();
58  case 2: return test<short, write>();
59  case 4: return test<int, write>();
60  case 8: return test<long long, write>();
61  }
62}
63
64int main(int argc, char** argv) {
65  int size = 8;
66  bool write = true;
67  if (argc > 1) {
68    size = atoi(argv[1]);
69    if (size != 1 && size != 2 && size != 4 && size != 8)
70      size = 8;
71  }
72  if (argc > 2)
73    write = false;
74  printf("%s%d\n", write ? "write" : "read", size);
75  if (write)
76    testw<true>(size);
77  else
78    testw<false>(size);
79  return 0;
80}
81