Einbindung von Multi-Threading und effizienter Synchronisation in den SVM-Fortran-Compiler

Programming parallel systems using shared memory comes easier and more natural. On systems lacking physical shared memory, software solutions offering virtual shared memory are available. An example of such a solution is ASVM running on the Intel Paragon XP/S. The virtual shared memory is organized in pages: accessing an item which is not stored locally causes a page fault which triggers the transmission of the referred page. The latency of ASVM for pcoessing such a page fault amounts to several milliseconds. SVM-Fortran is an language extension to Fortran 77 for parallel systems with virtual shared memory. The extensions are implemented using a precompiler and a run-time library. To hide the mentioned latencies in conjunction with page faults, multithreading was introduced into SVM-Fortran. If a thread causes a page fault, another thread will work on a different part of the data. This paper describes the principles of multithreading and efficient synchronization algorithms for different classes of parallel systems (UMA, NUMA, NORMA). It illustrates the implementation of multithreading into the precompiler and the run-time library and evaluates the effects of multithreading by performing synthetical and practical benchmarks. The results demonstrate the fundamental efficiency of the principle. (orig.)SIGLEAvailable from TIB Hannover: RA 831(3443) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman