%0 Report %D 1999 %T XMT-M: A Scalable Decentralized Processor %A Berkovich,Efraim %A Nuzman,Joseph %A Franklin,Manoj %A Jacob,Bruce %A Vishkin, Uzi %K Technical Report %X A defining challenge for research in computer science and engineering hasbeen the ongoing quest for reducing the completion time of a single computation task. Even outside the parallel processing communities, there is little doubt that the key to further progress in this quest is to do parallel processing of some kind. A recently proposed parallel processing framework that spans the entire spectrum from (parallel) algorithms to architecture to implementation is the explicit multi-threading (XMT) framework. This framework provides: (i) simple and natural parallel algorithms for essentially every general-purpose application, including notoriously difficult irregular integer applications, and (ii) a multi-threaded programming model for these algorithms which allows an ``independence-of-order'' semantics: every thread can proceed at its own speed, independent of other concurrent threads. To the extent possible, the XMT framework uses established ideas in parallel processing. This paper presents XMT-M, a microarchitecture implementation of the XMT model that is possible with current technology. XMT-M offers an engineering design point that addresses four concerns: buildability, programmability, performance, and scalability. The XMT-M hardware is geared to execute multiple threads in parallel on a single chip: relying on very few new gadgets, it can execute parallel threads without busy-waits! Existing code can be run on XMT-M as a single thread without any modifications, thereby providing backward compatibility for commercial acceptance. Simulation-based studies of XMT-M demonstrate considerable improvements in performance relative to the best serial processor even for small, and therefore practical, input sizes. (Also cross-referenced as UMIACS-TR-99-55) %I Instititue for Advanced Computer Studies, Univ of Maryland, College Park %V UMIACS-TR-99-55 %8 1999/10/09/ %G eng %U http://drum.lib.umd.edu//handle/1903/1030