naive-future-for-cpu-bound-operation.dart

blocking.dart

void main() {
  final then = DateTime.now();
  print(then);
  final r = veryLongRunningCpuBoundFunction(9);
  final now = DateTime.now();
  print('${now.difference(then)} later, the result is $r');
}

int veryLongRunningCpuBoundFunction(int param) {
  for (var i = 0; i < param; i++) {
    if (param > 0) veryLongRunningCpuBoundFunction(param - 1);
  }
  return 42;
}
// takes around 0.009391 seconds on Macbook Pro 2013

naive-future-for-cpu-bound-operation.dart

void main() async {
  final then = DateTime.now();
  print(then);
  final r = await veryLongRunningCpuBoundFunction(9);
  final now = DateTime.now();
  print('${now.difference(then)} later, the result is $r');
}

Future<int> veryLongRunningCpuBoundFunction(int param) async {
  for (var i = 0; i < param; i++) {
    if (param > 0) await veryLongRunningCpuBoundFunction(param - 1);
  }
  return 42;
}
// takes around 1.716475 seconds on Macbook Pro 2013