M-PVM: An Implementation of PVM for Multithreaded and Shared-Memory Environments

M-PVM is an implementation of PVM designed to work efficiently in parallel architectures supporting multithreading and the shared memory model. In particular, the current M-PVM implementation is running within MULPLIX, a Unix-like operating system designed to efficiently support parallel applications running on MUL TIPLUS, a distributed shared memory parallel computer under development at the Federal University of Rio de Janeiro. M-PVM is a parallel programming library built on top of the MULPLIX parallel programming primitives. Within M-PVM, PVM tasks are mapped onto MULPLIX threads. Two approaches have been adopted for the implementation ofthe message passing primitives. In the first approach a singlc copy of the message in memory is sharcd by ali destination M-PVM tasks. The second approach replicates the message for every destination task but rcquires less synchronization. MPVM is not totally compatiblc with standard PVM but offers an environment which simplifies the portability of PVM applications to multithreaded shared memory platforms, in most cases, with performance improvements. Experimental results comparing the performance o f M-PVM and PVM applications running on a 4-processor Sparcstation 20 under Solaris 2.5 are prcsented. These results show that M-PVM can produce speed-up gains in the range of 5 to I 0% in relation to PVM.