Get current CPU limit for subflows.

def _GetSubFlowCPULimit(self):
    """Get current CPU limit for subflows."""

    subflow_cpu_limit = None

    if self.runner_args.per_client_cpu_limit:
      subflow_cpu_limit = self.runner_args.per_client_cpu_limit

    if self.runner_args.cpu_limit:
      cpu_usage_data = self.context.client_resources.cpu_usage
      remaining_cpu_quota = (
          self.runner_args.cpu_limit - cpu_usage_data.user_cpu_time -
          cpu_usage_data.system_cpu_time)
      if subflow_cpu_limit is None:
        subflow_cpu_limit = remaining_cpu_quota
      else:
        subflow_cpu_limit = min(subflow_cpu_limit, remaining_cpu_quota)

      if subflow_cpu_limit == 0:
        raise RuntimeError("Out of CPU quota.")

    return subflow_cpu_limit