A machine independent interface for lightweight threads

Recently, lightweight thread libraries have become a common entity to support concurrent programming on shared memory multiprocessors. However, the disparity between primitives offered by operating systems creates a challenge for those who wish to create portable lightweight thread packages. What should be the interface between the machine-independent and machine-dependent parts of the thread library? We have implemented a portable lightweight thread library on top of Unix on a KSR-1 supercomputer, BBN Butterfly multiprocessor, SGI multiprocessor, Sequent multiprocessor and Sun 3/4 family of uniprocessors. This paper first compares the nature and performance of the OS primitives offered by these machines. We then present procedure-level abstraction that is efficiently implementable on all the architectures and is a sufficient base upon which a user-level thread package can be built.