While programmers know that memory representation of data structures can have significant effects on performance, compiler support to optimize the layout of those structures is an under-explored field. Prior work has optimized the layout of individual, non-recursive structures without considering how collections of those objects in linked or recursive data structures are laid out. This work introduces Marmoset, a compiler that optimizes the layouts of algebraic datatypes, with a special focus on producing highly optimized, packed data layouts where recursive structures can be traversed with minimal pointer chasing. Marmoset performs an analysis of how a recursive ADT is used across functions to choose a global layout that promotes simple, strided access for that ADT in memory. It does so by building and solving a constraint system to minimize an abstract cost model, yielding a predicted efficient layout for the ADT. Marmoset then builds on top of Gibbon, a prior compiler for packed, mostly-serial representations, to synthesize optimized ADTs. We show experimentally that Marmoset is able to choose optimal layouts across a series of microbenchmarks and case studies, outperforming both Gibbon’s baseline approach, as well as MLton, a Standard ML compiler that uses traditional pointer-heavy representations.
@InProceedings{singhal_et_al:LIPIcs.ECOOP.2024.38, author = {Singhal, Vidush and Koparkar, Chaitanya and Zullo, Joseph and Pelenitsyn, Artem and Vollmer, Michael and Rainey, Mike and Newton, Ryan and Kulkarni, Milind}, title = {{Optimizing Layout of Recursive Datatypes with Marmoset: Or, Algorithms + Data Layouts = Efficient Programs}}, booktitle = {38th European Conference on Object-Oriented Programming (ECOOP 2024)}, pages = {38:1--38:28}, series = {Leibniz International Proceedings in Informatics (LIPIcs)}, ISBN = {978-3-95977-341-6}, ISSN = {1868-8969}, year = {2024}, volume = {313}, editor = {Aldrich, Jonathan and Salvaneschi, Guido}, publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik}, address = {Dagstuhl, Germany}, URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2024.38}, URN = {urn:nbn:de:0030-drops-208875}, doi = {10.4230/LIPIcs.ECOOP.2024.38}, annote = {Keywords: Tree traversals, Compilers, Data layout optimization, Dense data layout} }
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