CARAT: a case for virtual memory through compiler- and runtime-based address translation

Suchy, Brian; Campanoni, Simone; Hardavellas, Nikos; Dinda, Peter A.

doi:10.1145/3385412.3385987

Cited by 13 publications

(12 citation statements)

References 38 publications

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“…Other Benchmarks and Workloads: Although CARAT CAKE is not evaluated on an extremely diverse set of workloads, there is no particular reason why a CARAT system could not feasibly and efficiently run them. This is in part supported by the results from our prior paper [81], which shows a much wider range of benchmarks from NAS, PARSEC, and Mantevo. We also note that for overlapping benchmarks, the overheads presented in the original paper have actually gone down in this paper due to efforts in compiler optimization.…”

Section: Generality and Future Worksupporting

confidence: 67%

“…Suchy et al [81] argue that a modern OS running programs written in unmanaged languages can achieve performant memory management and protection without hardware support. A naive approach to purely software-based memory management and protection is, of course, destined to be horrifically slow.…”

Section: Carat Concepts and Prior Resultsmentioning

confidence: 99%

“…The original CARAT paper [81] developed a prototype of this system within the context of LLVM. Our runtime system is a user-level library in C++.…”

Section: User-level Prototype and Limitationsmentioning

confidence: 99%

“…This approach has been limited to managed languages, where it serves a different purpose than paging in a general-purpose OS which can run any arbitrary code in a user process. However, we have recently made a case for Compiler-And Runtime-based Address Translation (CARAT), an approach to general-purpose software-based memory management based on a compiler/kernel codesign [81].…”

Section: Introductionmentioning

confidence: 99%

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CARAT CAKE: replacing paging via compiler/kernel cooperation

Suchy

Ghosh

Kersnar

et al. 2022

Proceedings of the 27th ACM International Conference on Architectural Support for Programming Languages and Operating Systems

Self Cite

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Virtual memory, specifically paging, is undergoing significant innovation due to being challenged by new demands from modern workloads. Recent work has demonstrated an alternative softwareonly design that can result in simplified hardware requirements, even supporting purely physical addressing. While we have made the case for this Compiler-And Runtime-based Address Translation (CARAT) concept, its evaluation was based on a user-level prototype. We now report on incorporating CARAT into a kernel, forming Compiler-And Runtime-based Address Translation for CollAborative Kernel Environments (CARAT CAKE). In our implementation, a Linux-compatible x64 process abstraction can be based either on CARAT CAKE, or on a sophisticated paging implementation. Implementing CARAT CAKE involves kernel changes and compiler optimizations/transformations that must work on all code in the system, including kernel code. We evaluate CARAT CAKE in comparison with paging and find that CARAT CAKE is able to achieve the functionality of paging (protection, mapping, and movement properties) with minimal overhead. In turn, CARAT CAKE allows significant new benefits for systems including energy savings, larger L1 caches, and arbitrary granularity memory management.

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Section: Generality and Future Worksupporting

confidence: 67%

Section: Carat Concepts and Prior Resultsmentioning

confidence: 99%

“…The original CARAT paper [81] developed a prototype of this system within the context of LLVM. Our runtime system is a user-level library in C++.…”

Section: User-level Prototype and Limitationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

CARAT CAKE: replacing paging via compiler/kernel cooperation

Suchy

Ghosh

Kersnar

et al. 2022

Proceedings of the 27th ACM International Conference on Architectural Support for Programming Languages and Operating Systems

Self Cite

View full text Add to dashboard Cite

show abstract

“…This can be very efficient, by avoiding translation for that region entirely, but it requires application changes, causes fragmentation in memory through requiring contiguity and is unsuitable for applications without a single distinct large region. CARAT [39] replaces paging with software management of physical memory, through a trusted compiler interface. This avoids the need of any paging hardware, at the expense of slowdown.…”

Section: Alternative Virtual-memory Translationmentioning

confidence: 99%

Compendia: reducing virtual-memory costs via selective densification

Ainsworth

Jones

2021

Proceedings of the 2021 ACM SIGPLAN International Symposium on Memory Management

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Virtual-to-physical memory translation is becoming an increasingly dominant cost in workload execution; as data sizes scale, up to four memory accesses are required per translation, and 24 in virtualised systems. However, the radix trees in use today to hold these translations have many favourable properties, including cacheability, ability to fit in conventional 4 KiB page frames, and a sparse representation. They are therefore unlikely to be replaced in the near future.In this paper we argue that these structures are actually too sparse for modern workloads, so many of the overheads are unnecessary. Instead, where appropriate, we expand groups of 4 KiB layers, each able to translate 9 bits of address space, into a single 2 MiB layer, able to translate 18 bits in a single memory access. These fit in the standard huge-page allocations used by most conventional operating systems and architectures. With minor extensions to the page-table-walker structures to support these, and aid in their cacheability, we can reduce memory accesses per walk by 27%, or 56% for virtualised systems, without significant memory overhead.CCS Concepts: • Software and its engineering → Virtual memory; • Computer systems organization → Architectures.

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NOELLE Offers Empowering LLVM Extensions

Matni

Deiana

et al. 2022

2022 IEEE/ACM International Symposium on Code Generation and Optimization (CGO)

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CARAT: a case for virtual memory through compiler- and runtime-based address translation

Cited by 13 publications

References 38 publications

CARAT CAKE: replacing paging via compiler/kernel cooperation

CARAT CAKE: replacing paging via compiler/kernel cooperation

Compendia: reducing virtual-memory costs via selective densification

NOELLE Offers Empowering LLVM Extensions

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