| Technical Report| [Lind:05] | Götz Lindenmaier, Structure Splitting and Inheritance, Nr. 2005-7, 3 2005.
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AbstractThe increasing gap between memory and
processor performance drives the research for cache optimizations.
Recently research concentrates on optimizing pointer based
applications. Structure splitting is an important enabling
transformation for optimizations that improve the layout of
dynamic data structures. Previous work has shown the potential of
structure splitting in runtime optimizations. This paper
discusses issues of structure splitting applied to inheritance
hierarchies of object oriented languages. Inheritance requires
similar layout of compound types to simplify type casts.
Structure splitting, in contrast, requires a layout that is
tailored for a single type. Therefore compatibility between the
split type and its super and sub-types is lost. This issue was
not addressed by previous work. We explain several strategies to
deal with this type compatibility issue and implement two as a
compiler optimization. Our experiments show that a careful choice
of the strategy is necessary, as they either increase the overhead
for accessing cache-neutral data, or they can not achieve the full
possible speed up for cache-critical data. Nevertheless, both
approaches show considerable speed ups of our tests.
Authors
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