compiler-rt/lib/tsan/benchmarks/mop.cpp

   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>
  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>
  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>
  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
  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 }