Method write_file

src/client/SyntheticClient.cc:2015–2078

}

int SyntheticClient::write_file(string& fn, int size, loff_t wrsize)   // size is in MB, wrsize in bytes
{
  //uint64_t wrsize = 1024*256;
  char *buf = new char[wrsize+100];   // 1 MB
  memset(buf, 7, wrsize);
  int64_t chunks = (uint64_t)size * (uint64_t)(1024*1024) / (uint64_t)wrsize;
  UserPerm perms = client->pick_my_perms();

  int fd = client->open(fn.c_str(), O_RDWR|O_CREAT, perms);
  dout(5) << "writing to " << fn << " fd " << fd << dendl;
  if (fd < 0) {
    delete[] buf;
    return fd;
  }

  utime_t from = ceph_clock_now();
  utime_t start = from;
  uint64_t bytes = 0, total = 0;


  for (loff_t i=0; i<chunks; i++) {
    if (time_to_stop()) {
      dout(0) << "stopping" << dendl;
      break;
    }
    dout(2) << "writing block " << i << "/" << chunks << dendl;
    
    // fill buf with a 16 byte fingerprint
    // 64 bits : file offset
    // 64 bits : client id
    // = 128 bits (16 bytes)
    uint64_t *p = (uint64_t*)buf;
    while ((char*)p < buf + wrsize) {
      *p = (uint64_t)i*(uint64_t)wrsize + (uint64_t)((char*)p - buf);      
      p++;
      *p = client->get_nodeid().v;
      p++;
    }

    client->write(fd, buf, wrsize, i*wrsize);
    bytes += wrsize;
    total += wrsize;

    utime_t now = ceph_clock_now();
    if (now - from >= 1.0) {
      double el = now - from;
      dout(0) << "write " << (bytes / el / 1048576.0) << " MB/sec" << dendl;
      from = now;
      bytes = 0;
    }
  }

  client->fsync(fd, true);

  utime_t stop = ceph_clock_now();
  double el = stop - start;
  dout(0) << "write total " << (total / el / 1048576.0) << " MB/sec ("
	  << total << " bytes in " << el << " seconds)" << dendl;