Traditional centralized virtual memory system design encounters severe scalability problems, which impede the multithreaded applications’ performance increment on many-core systems. In this paper, we propose a decentralized system model to scale the VM systems for many-cores. Our model improves system parallelism by avoiding resource sharing and minimizing state coordination. By applying the model, we build a novel scalable virtual memory system called MedusaVM+. MedusaVM+ presents a decentralized system architecture, which avoids resource conflicts or cache line contention among processors or threads. Furthermore, MedusaVM+ provides a scalable address space by incorporating decentralized VM space management and a hybrid page table design. Critical system services and internal system operations, such as TLB coherence, are also fully optimized to maximize the system parallelism. Our prototype system is implemented based on the Linux kernel 4.4.0 and glibc 2.23. Experimental results evaluated on a 72-core machine demonstrate that MedusaVM+ scales much better than the state-of-the-art systems and decreases the memory consumption by up to 27 × compared with current approaches. For microbenchmark experiments, MedusaVM+ achieves nearly linear performance speedup. When evaluated with multithreaded applications, MedusaVM+ also outperforms other systems by up to a factor of 4.5 × .

传统的集中式虚拟内存系统设计遇到严重的可伸缩性问题，从而阻碍了多线程应用程序在多核系统上的性能提升。在本文中，我们提出了一种去中心化的系统模型，以针对多核扩展VM系统。我们的模型通过避免资源共享和最小化状态协调来改善系统并行性。通过应用该模型，我们构建了一个名为MedusaVM +的新型可扩展虚拟内存系统。MedusaVM +提出了一种分散的系统架构，该架构避免了资源冲突或处理器或线程之间的缓存线争用。此外，MedusaVM +通过结合分散的VM空间管理和混合页表设计，提供了可扩展的地址空间。关键系统服务和内部系统操作（例如TLB一致性）也得到了充分优化，以最大程度地提高系统并行性。我们的原型系统是基于Linux内核4.4.0和glibc 2.23实现的。在72核计算机上评估的实验结果表明，MedusaVM +的扩展性比最新系统好得多，与当前方法相比，其内存消耗最多减少了27倍。对于微基准实验，MedusaVM +实现了近乎线性的性能加速。在多线程应用程序中进行评估时，MedusaVM +的性能也比其他系统高出4.5倍。