Constructing a high-performance garbage collector is hard. Constructing a fully concurrent ‘on-the-fly’ compacting collector is much more so. We describe our experience of implementing the Sapphire algorithm as the first on-the-fly, parallel, replication copying, garbage collector for the Jikes RVM Java virtual machine (JVM). In part, we explain our innovations such as copying with hardware and software transactions, on-the-fly management of Java’s reference types, and simple, yet correct, lock-free management of volatile fields in a replicating collector. We fully evaluate, for the first time, and using realistic benchmarks, Sapphire’s performance and suitability as a low latency collector. An important contribution of this work is a detailed description of our experience of building an on-the-fly copying collector for a complete JVM with some assurance that it is correct. A key aspect of this is model checking of critical components of this complicated and highly concurrent system.

中文翻译：

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交易蓝宝石

构建一个高性能的垃圾收集器很难。构建一个完全并发的“on-the-fly”压缩收集器更是如此。我们描述了我们将 Sapphire 算法实现为 Jikes RVM Java 虚拟机 (JVM) 的第一个即时、并行、复制复制、垃圾收集器的经验。在某种程度上，我们解释了我们的创新，例如使用硬件和软件事务进行复制、Java 引用类型的动态管理以及复制收集器中对易失性字段的简单但正确的无锁管理。我们首次使用现实基准全面评估 Sapphire 作为低延迟收集器的性能和适用性。这项工作的一个重要贡献是详细描述了我们为完整的 JVM 构建动态复制收集器的经验，并确保它是正确的。其中一个关键方面是对这个复杂且高度并发的系统的关键组件进行模型检查。