Real-time Operating System, Collaborative Design Research

Because of the increasing demand for higher computational power and performance, as well as the demand for shorter time to market, the dynamic real-time behaviors in embedded software have also been more complexity. Since the dynamic real-time behaviors are implemented by real-time operating systems (RTOSes), it is essential to do research on RTOSes with different applications. On the other hand, reconfigurable hardware devices have huge densities and are partially reconfigurable, which means that multitasks in hardware not only can run simultaneously, but also can be reconfigured at run time. This makes reconfigurable platforms an ideal target for many modern embedded systems. A rather new line of research is engaged in the constructions of RTOS since traditional RTOSes lack support for reconfigurable embedded platforms. The main contributions of this paper are as following:Firstly, because high level system models are used in system level synthesis for early design exploration, RTOS abstract modeling is absolutely necessary. But it is extremely difficult to model higher-level RTOSes because RTOSes have close relationship with the hardware implementation details. We propose a RTOS model to provide the key features typically available in any RTOS, also in RTOSes with reconfigurable hardware tasks.Secondly, Based on the essential differences between software-tasks and hardware-tasks, this paper presents and implements a RTOS for reconfigurable systems using uniform multi-task model, called SHUM-UCOS (Software-Tasks Hardware-Tasks Uniform Management UCOS), which is designed with the UCOSII as prototype. SHUM-UCOS also defines two types of standard hardware-task interface, which can support bus protocol and point-to-point protocol separately. And experiments show that SHUM-UCOS can shorten the transition time from software implementations to hardware implementations, along with the performance improvement.Thirdly, dealing with online scheduling of tasks to partially reconfigurable devices. There are two more modules for hardware task scheduler: placer and loader. Placer is to find appropriate place in reconfigurable devices and loader is to do the reconfiguration for hardware tasks. We propose a fast on-line scheduling for reconfigurable real-time tasks, which will adopt the scheduling principle of earliest...