Bringing Parallel Performance to Python with Domain-Specific Selective Just-in-Time Specialization

TitleBringing Parallel Performance to Python with Domain-Specific Selective Just-in-Time Specialization
Publication TypeConference Paper
Year of Publication2011
AuthorsKamil, S., Coetzee D., & Fox A.
Conference NamePython for Scientific Computing Conference 2011
Conference LocationAustin, TX

Abstract—Today’s productivity programmers, such as scientists who need to
write code to do science, are typically forced to choose between productive
and maintainable code with modest performance (e.g. Python plus native
libraries such as SciPy [SciPy]) or complex, brittle, hardware-specific code that
entangles application logic with performance concerns but runs two to three
orders of magnitude faster (e.g. C++ with OpenMP, CUDA, etc.). The dynamic
features of modern productivity languages like Python enable an alternative
approach that bridges the gap between productivity and performance. SEJITS
(Selective, Embedded, Just-in-Time Specialization) embeds domain-specific
languages (DSLs) in high-level languages like Python for popular computational
kernels such as stencils, matrix algebra, and others. At runtime, the DSLs
are “compiled” by combining expert-provided source code templates specific
to each problem type, plus a strategy for optimizing an abstract syntax tree
representing a domain-specific but language-independent representation of the
problem instance. The result is efficiency-level (e.g. C, C++) code callable
from Python whose performance equals or exceeds that of handcrafted code,
plus performance portability by allowing multiple code generation strategies
within the same specializer to target different hardware present at runtime, e.g.
multicore CPUs vs. GPUs. Application writers never leave the Python world, and
we do not assume any modification or support for parallelism in Python itself.
We present Asp (“Asp is SEJITS for Python”) and initial results from several
domains. We demonstrate that domain-specific specializers allow highlyproductive
Python code to obtain performance meeting or exceeding expertcrafted
low-level code on parallel hardware, without sacrificing maintainability or

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