Toward Dynamic. Multiprocessor Real-Time Threads

Publisher Summary This chapter describes some of the research issues and solutions surrounding the development of a real-time threads package for multiprocessor systems. The package involved is based on Mach threads and has been implemented on standard UNIX platforms and on 32-node BBN Butterfly multiprocessor. It has also been used as a portable basis for the construction of parallel real-time applications and multiprocessor operating system kernels. The essential idea underlying real-time threads is that the schedulability of a thread should be guaranteed before it is actually run, not only at the time of program compilation but also at the time of thread creation. Specifically, the real-time threads package guarantees the schedulability of threads being created prior to their execution, assuming that thread deadlines, start times, and maximum execution times are known. The second main idea underlying real-time threads is that minimum functionality should be offered by the threads package itself. Specifically, when scheduling, guarantees cannot be made by the package's underlying algorithms.