Though Chapel has been designed to ultimately yield high performance, our focus to date has predominantly been on implementing its features correctly and providing user-supported control of features like array implementations, loop schedules, and architectural descriptions. To that end, the current compiler is lacking several key optimizations and therefore is often not competitive with hand-coded C, Fortran, MPI, and the like. We are currently working on closing this gap.
Once your program is correct and you are ready to do a performance study, make sure to compile with the --fast flag. This is a compiler meta-flag that turns off several execution-time correctness checks (bounds checks, NULL pointer checks, etc.) and turns on C-level optimizations. See the 'chpl' man page for details.
To characterize Chapel performance, generally speaking...
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single-locale (CHPL_COMM=none | --local) compilations perform better than multi-locale (CHPL_COMM!=none | --no-local) compilations;
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1D loops/arrays perform better than multidimensional cases;
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codes with structured communication (e.g., stencils) tend not to perform competitively with hand-coded computations, whereas embarrassingly parallel and unstructured communications tend to be more competitive. The reason for this is that Chapel communications currently tend to be very fine-grain and demand-driven unless array assignments are used to move chunks of data between locales.
We are currently working to improve Chapel performance with each release and are making significant strides. To track our progress over time, refer to:
http://chapel.sourceforge.net/perf/
From this page, you can track performance tests, either on a nightly or release-over-release basis. Interested users are encouraged to submit their own performance tests back to the project for tracking on this page.