message: add macro CHECKPOINT_VERBOSE to evaluate our checkpoint technique
diff: #define PAGE_MAP_BITS 9
  #define PAGE_LEVELS 4
  +#define CHECKPOINT_VERBOSE 1
  +
  #define kvm_ioctl(fd, cmd, arg) ({ \
  const int ret = ioctl(fd, cmd, arg); \
  if(ret == -1) \
  @@ -920,9 +922,9 @@ int uhyve_init(char *path)
  fscanf(f, "memory size: 0x%zx\n", &guest_size);
  fscanf(f, "checkpoint number: %u\n", &no_checkpoint);
  fscanf(f, "entry point: 0x%zx", &elf_entry);
  -
  +#if CHECKPOINT_VERBOSE
  printf("Restart from checkpoint %u (ncores %d, mem size 0x%zx)\n", no_checkpoint, ncores, guest_size);
  -
  +#endif
  fclose(f);
  } else {
  const char* hermit_memory = getenv("HERMIT_MEM");
  @@ -981,9 +983,11 @@ static void timer_handler(int signum)
  struct stat st = {0};
  const size_t flag = no_checkpoint > 0 ? PG_DIRTY : PG_ACCESSED;
  char fname[MAX_FNAME];
  +#if CHECKPOINT_VERBOSE
  struct timeval begin, end;
  gettimeofday(&begin, NULL);
  +#endif
  if (stat("checkpoint", &st) == -1)
  mkdir("checkpoint", 0700);
  @@ -1075,11 +1079,12 @@ static void timer_handler(int signum)
  fclose(f);
  +#if CHECKPOINT_VERBOSE
  gettimeofday(&end, NULL);
  size_t msec = (end.tv_sec - begin.tv_sec) * 1000;
  msec += (end.tv_usec - begin.tv_usec) / 1000;
  printf("Create checkpoint %u in %zd ms\n", no_checkpoint, msec);
  -
  +#endif
  no_checkpoint++;
  }
  