UNIFICO: Thread Migration in Heterogeneous-ISA CPUs without State Transformation

Nikolaos Mavrogeorgis, Christos Vasiladiotis, Pei Mu, Amir Khordadi, Björn Franke, Antonio Barbalace

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract / Description of output

Heterogeneous-ISA processor designs have attracted considerable research interest. However, unlike their homogeneous-ISA counterparts, explicit software support for bridging ISA heterogeneity is required. The lack of a compilation toolchain ready to support heterogeneous-ISA targets has been a major factor hindering research in this exciting emerging area. For any such compiler “getting right” the mechanics involved in state transformation upon migration and doing this efficiently is of critical importance. In particular, any runtime conversion of the current program stack from one architecture to another would be prohibitively expensive. In this paper, we design and develop Unifico, a new multi-ISA compiler that generates binaries that maintain the same stack layout during their execution on either architecture. Unifico avoids the need for runtime stack transformation, thus eliminating overheads associated with ISA migration. Additional responsibilities of the Unifico compiler backend include maintenance of a uniform ABI and virtual address space across ISAs. Unifico is implemented using the LLVM compiler infrastructure, and we are currently targeting the x86-64 and ARMv8 ISAs. We have evaluated Unifico across a range of compute-intensive NAS benchmarks and show its minimal impact on overall execution time, where less than 6% overhead is introduced on average. When compared against the state-of-the-art Popcorn compiler, Unifico reduces binary size overhead from ∼200% to ∼10%, whilst eliminating the stack transformation overhead during ISA migration.
Original languageEnglish
Title of host publicationCC 2024: Proceedings of the 33rd ACM SIGPLAN International Conference on Compiler Construction
PublisherAssociation for Computing Machinery
ISBN (Electronic)9798400705076
Publication statusPublished - 20 Feb 2024
EventACM SIGPLAN 2024 International Conference on Compiler Construction - Edinburgh, United Kingdom
Duration: 2 Mar 20243 Mar 2024
Conference number: 33


ConferenceACM SIGPLAN 2024 International Conference on Compiler Construction
Abbreviated titleCC '24
Country/TerritoryUnited Kingdom
Internet address


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