A new task-scheduling algorithm with feedback latency is suggested for real-time control systems, which considers both point of views: control theoretic and real-time computing. Building a real-time control system has two steps in general: In controller design stage, a control performance index is defined and a controller is designed which optimizes the given performance index while maintaining stability and rejecting disturbances. In implementation stage, a set of controllers constitutes multiple control tasks, and scheduled to run on microprocessors, which should be schedulable with limited computing resources. In this paper, we reveal that the control performance depends not only on control period but also on {\em feedback latency} (latency from sensing, computation to actuation) with more impact. We formulate a new task-scheduling problem with control performance index including feedback latency. An iterative search algorithm is suggested, which is based on feedback latency computation method. An illustrative example demonstrated the applicability of the proposed method.