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PRODID:-//Microsoft Corporation//Outlook MIMEDIR//EN
VERSION:1.0
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DTSTART:20111117T233000Z
DTEND:20111118T000000Z
LOCATION:TCC 305
DESCRIPTION;ENCODING=QUOTED-PRINTABLE:ABSTRACT: PGAS languages like UPC provide a global name space to the user. This facilitates the expression of parallel algorithms, since communication is implicit, as compared to message passing where communication is explicit. This is especially convenient when writing irregular applications. However, programming in a shared memory style may result in poor performance. The problem may be due to weaknesses of current implementations of PGAS languages or limitations inherent in these languages. To clarify which is the case, we discuss an implementation in UPC of a representative irregular application, namely the Barnes-Hut algorithm. We have implemented optimizations that have improved the performance above 1600 times compared with a baseline, shared-memory style implementation. Most of these optimizations could be performed with limited changes in the source code using an enhanced run-time and a few language extensions or pragmas. We then discuss the implications to the programmer, the compiler and PGAS languages themselves.
SUMMARY:Optimizing the Barnes-Hut Algorithm in UPC
PRIORITY:3
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