@article{kumar_asokan_shivshankar_dean_2007, title={Efficient software implementation of embedded communication protocol controllers using asynchronous software thread integration with time- and space-efficient procedure calls}, volume={6}, ISSN={["1558-3465"]}, DOI={10.1145/1210268.1210270}, abstractNote={The overhead of context switching limits efficient scheduling of multiple concurrent threads on a uniprocessor when real-time requirements exist. A software-implemented protocol controller may be crippled by this problem. The available idle time may be too short to recover through context switching, so only the primary thread can execute during message activity, slowing the secondary threads and potentially missing deadlines. Asynchronous software thread integration (ASTI) uses coroutine calls and integration, letting threads make independent progress efficiently, and reducing the needed context switches. We demonstrate the methods with a software implementation of an automotive communication protocol (J1850) and several secondary threads.}, number={1}, journal={ACM TRANSACTIONS ON EMBEDDED COMPUTING SYSTEMS}, author={Kumar, Nagendra J. and Asokan, Vasanth and Shivshankar, Siddhartha and Dean, Alexander G.}, year={2007}, month={Feb} }
 @article{kumar_shivshankar_dean_2004, title={Asynchronous software thread integration for efficient software implementations of embedded communication protocol controllers}, volume={39}, ISSN={["1558-1160"]}, DOI={10.1145/998300.997170}, abstractNote={
            The overhead of context-switching limits efficient scheduling of multiple concurrent threads on a uniprocessor when real-time requirements exist. Existing software thread integration (STI) methods reduce context switches, but only provide synchronous thread progress within integrated functions. For the remaining, non-integrated portions of the secondary threads to run and avoid starvation, the primary thread must have adequate amounts of coarse-grain idle time (longer than two context-switches). We have developed
            asynchronous
            software thread integration (ASTI) methods which address starvation through the efficient use of coroutine calls and integration. ASTI allows threads to make independent progress efficiently and reduces the number of context switches needed through integration.Software-implemented protocol controllers are crippled by this problem; the primary thread "bit-bangs" each bit of a message onto or off of the bus, leaving only fragments of idle time shorter than a bit time. This fragmented time may be too short to recover through context switching, so only the primary thread can execute during message transmission or reception, slowing the secondary threads and potentially making them miss their deadlines. ASTI simplifies the implementation of embedded communication protocols on low-cost, moderate speed (1 - 100 MHz, 8- and 16-bit) microcontrollers. We demonstrate ASTI by replacing a standard automotive communication protocol controller (J1850) with software and generic hardware. Secondary thread performance improves significantly when compared with a traditional interrupt-based software approach.
          }, number={7}, journal={ACM SIGPLAN NOTICES}, author={Kumar, NJ and Shivshankar, S and Dean, AG}, year={2004}, month={Jul}, pages={37–46} }