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| // Synthetic benchmark for __tsan_read/write{1,2,4,8}.
// As compared to mini_bench_local/shared.cc this benchmark passes through
// deduplication logic (ContainsSameAccess).
// First argument is access size (1, 2, 4, 8). Second optional arg switches
// from writes to reads.
#include <pthread.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <linux/futex.h>
#include <sys/syscall.h>
#include <sys/time.h>
template<typename T, bool write>
void* thread(void *arg) {
const int kSize = 2 << 10;
static volatile long data[kSize];
static volatile long turn;
const int kRepeat = 1 << 17;
const int id = !!arg;
for (int i = 0; i < kRepeat; i++) {
for (;;) {
int t = __atomic_load_n(&turn, __ATOMIC_ACQUIRE);
if (t == id)
break;
syscall(SYS_futex, &turn, FUTEX_WAIT, t, 0, 0, 0);
}
for (int j = 0; j < kSize; j++) {
if (write) {
((volatile T*)&data[j])[0] = 1;
((volatile T*)&data[j])[sizeof(T) == 8 ? 0 : 1] = 1;
} else {
T v0 = ((volatile T*)&data[j])[0];
T v1 = ((volatile T*)&data[j])[sizeof(T) == 8 ? 0 : 1];
(void)v0;
(void)v1;
}
}
__atomic_store_n(&turn, 1 - id, __ATOMIC_RELEASE);
syscall(SYS_futex, &turn, FUTEX_WAKE, 0, 0, 0, 0);
}
return 0;
}
template<typename T, bool write>
void test() {
pthread_t th;
pthread_create(&th, 0, thread<T, write>, (void*)1);
thread<T, write>(0);
pthread_join(th, 0);
}
template<bool write>
void testw(int size) {
switch (size) {
case 1: return test<char, write>();
case 2: return test<short, write>();
case 4: return test<int, write>();
case 8: return test<long long, write>();
}
}
int main(int argc, char** argv) {
int size = 8;
bool write = true;
if (argc > 1) {
size = atoi(argv[1]);
if (size != 1 && size != 2 && size != 4 && size != 8)
size = 8;
}
if (argc > 2)
write = false;
printf("%s%d\n", write ? "write" : "read", size);
if (write)
testw<true>(size);
else
testw<false>(size);
return 0;
}
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