Function buffer_iterator

src/test/perf_local.cc:286–307

Measure the cost of creating an iterator and iterating over 10 chunks in a buffer.

// Measure the cost of creating an iterator and iterating over 10
// chunks in a buffer.
double buffer_iterator()
{
  bufferlist b;
  const char s[] = "abcdefghijklmnopqrstuvwxyz";
  bufferptr ptr(s, sizeof(s));
  for (int i = 0; i < 5; i++) {
    b.append(ptr, i, 5);
  }
  int count = 100000;
  int sum = 0;
  uint64_t start = Cycles::rdtsc();
  for (int i = 0; i < count; i++) {
    auto it = b.cbegin();
    while (!it.end()) {
      sum += (static_cast<const char*>(it.get_current_ptr().c_str()))[it.get_remaining()-1];
      ++it;
    }
  }
  uint64_t stop = Cycles::rdtsc();
  discard(&sum);
  return Cycles::to_seconds(stop - start)/count;
}

// Implements the CondPingPong test.
class CondPingPong {