Function TimeParallelExecutors

be/src/benchmarks/thread-create-benchmark.cc:106–124

Times how long it takes to run num_threads 'executors', each of which spawns num_threads_per_executor empty threads, and to wait for all of them to finish.

// which spawns num_threads_per_executor empty threads, and to wait
// for all of them to finish.
void TimeParallelExecutors(int num_threads, int num_threads_per_executor,
    bool use_native_threads = true) {
  StopWatch sw;
  sw.Start();
  if (use_native_threads) {
    function<void ()> f =
        bind(NativeThreadStarter, num_threads_per_executor, EmptyThread);
    NativeThreadStarter(num_threads, f);
  } else {
    function<void ()> f =
        bind(ImpalaThreadStarter, num_threads_per_executor, EmptyThread);
    ImpalaThreadStarter(num_threads, f);
  }
  sw.Stop();
  cout << (use_native_threads ? "(Native):" : "(Impala):")
       << "Time to start up " << num_threads << " * " << num_threads_per_executor << " = "
       << num_threads * num_threads_per_executor << " threads: "
       << PrettyPrinter::Print(sw.ElapsedTime(), TUnit::CPU_TICKS) << endl;
}

int main(int argc, char **argv) {
  google::InitGoogleLogging(argv[0]);