Runtime Support for User-Level Ultra Lightweight Threads on Massively Parallel Distributed Memory Machines

Ultra-lightweight Thread (uThread) is a library package designed and optimized for user-level management of parallelism in a single application program running on distributed memory computers. Existing process management systems incur an unnecessarily high cost when used for the type of parallelism exploited within an application. By reducing the overhead of ownership protection and frequent context switches, uThread encourages both simplicity and performance. In addition, uThread provides various scheduling support to balance the system load. The uThread package reduces the cost of parallelism management to nearly the lower bound. This package has been successfully running on most distributed memory computers, such as Intel iPSC/860, Touchstone Delta, NCUBE, and TMC CM-5.