{"title":"Achieving Forward Progress Guarantee in Small Hardware Transactions","authors":"Mahita Nagabhiru;Gregory T. Byrd","doi":"10.1109/LCA.2024.3370992","DOIUrl":null,"url":null,"abstract":"Hardware-transactional-memory (HTM) manages to pique interest from academia and industry alike because of its potential to ease concurrent-programming without compromising on performance. It offers a simple “all-or-nothing” idea to the programmer, making a piece of code appear atomic in hardware. Despite this and many elegant HTM implementations in research, only best-effort HTM is available commercially. Best-effort HTM lacks forward progress guarantee making it harder for the programmer to create a concurrent scalable fallback path. This has made HTM's adaptability limited. With a scope to support a myriad of applications, HTMs do a trade off between design and verification complexity vs forward progress guarantee. In this letter, we argue that limiting the scope of applications helps HTM attain guaranteed forward progress. We support lock-free programs by using HTM as multi-word-atomics and demonstrate strategic design choices to achieve lock-freedom completely in hardware. We use lfbench, a lock-free micro-benchmark-suite, and Arm's best-effort HTM (ARM_TME) on the gem5 simulator, as our base. We demonstrate the performance tradeoffs between design choices of a deferral-based, NACK-based, and NACK-with-backoff approaches. We show that NACK-with-backoff performs better than the others without compromising scalability for both read- and write-intensive applications.","PeriodicalId":51248,"journal":{"name":"IEEE Computer Architecture Letters","volume":"23 1","pages":"53-56"},"PeriodicalIF":1.4000,"publicationDate":"2024-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"IEEE Computer Architecture Letters","FirstCategoryId":"94","ListUrlMain":"https://ieeexplore.ieee.org/document/10452802/","RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"COMPUTER SCIENCE, HARDWARE & ARCHITECTURE","Score":null,"Total":0}
引用次数: 0
Abstract
Hardware-transactional-memory (HTM) manages to pique interest from academia and industry alike because of its potential to ease concurrent-programming without compromising on performance. It offers a simple “all-or-nothing” idea to the programmer, making a piece of code appear atomic in hardware. Despite this and many elegant HTM implementations in research, only best-effort HTM is available commercially. Best-effort HTM lacks forward progress guarantee making it harder for the programmer to create a concurrent scalable fallback path. This has made HTM's adaptability limited. With a scope to support a myriad of applications, HTMs do a trade off between design and verification complexity vs forward progress guarantee. In this letter, we argue that limiting the scope of applications helps HTM attain guaranteed forward progress. We support lock-free programs by using HTM as multi-word-atomics and demonstrate strategic design choices to achieve lock-freedom completely in hardware. We use lfbench, a lock-free micro-benchmark-suite, and Arm's best-effort HTM (ARM_TME) on the gem5 simulator, as our base. We demonstrate the performance tradeoffs between design choices of a deferral-based, NACK-based, and NACK-with-backoff approaches. We show that NACK-with-backoff performs better than the others without compromising scalability for both read- and write-intensive applications.
期刊介绍:
IEEE Computer Architecture Letters is a rigorously peer-reviewed forum for publishing early, high-impact results in the areas of uni- and multiprocessor computer systems, computer architecture, microarchitecture, workload characterization, performance evaluation and simulation techniques, and power-aware computing. Submissions are welcomed on any topic in computer architecture, especially but not limited to: microprocessor and multiprocessor systems, microarchitecture and ILP processors, workload characterization, performance evaluation and simulation techniques, compiler-hardware and operating system-hardware interactions, interconnect architectures, memory and cache systems, power and thermal issues at the architecture level, I/O architectures and techniques, independent validation of previously published results, analysis of unsuccessful techniques, domain-specific processor architectures (e.g., embedded, graphics, network, etc.), real-time and high-availability architectures, reconfigurable systems.