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
15 template<typename T, bool write>
thread(void * arg)16 void* 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
46 template<typename T, bool write>
test()47 void 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
54 template<bool write>
testw(int size)55 void 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
main(int argc,char ** argv)64 int 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