CAP-OS: Operating system for runtime scheduling, task mapping and resource management on reconfigurable multiprocessor architectures

Operating systems traditionally handle the task scheduling of one or more application instances on a processor like hardware architecture. Novel runtime adaptive hardware exploits the dynamic reconfiguration on FPGAs, where hardware blocks are generated, started and terminated. This is similar to software tasks in well established operating system approaches. The hardware counterparts to the software tasks have to be transferred to the reconfigurable hardware via a configuration access port. This port enables the allocation of hardware blocks on the FPGA. Current reconfigurable hardware, like e.g. Xilinx Virtex 5 provide two internal configuration access ports (ICAPs), where only one of these ports can be accessed at one point of time. In e.g. a multiprocessor system on an FPGA, it can happen that multiple instances try to access these ports simultaneously. To prevent conflicts, the access to these ports as well as the hardware resource management needs to be controlled by a special purpose operating system running on an embedded processor. This special purpose operating system, called CAPOS (Configuration Access Port-Operating System), which will be presented in this paper, supports the clients using the configuration port with the service of priority-based access scheduling, hardware task mapping and resource management.