MedusaVM: Decentralizing virtual memory system for multithreaded applications on many-core

Abstract

Virtual memory system multiplexes the single physical memory for multiple running processes with two centralized resources, i.e., virtual memory space and page table hierarchy. However, for multithreaded applications running a single address space, current centralized VM system design encounters severe scalability bottlenecks and significantly impedes the application speedup increment on many-core systems. This paper proposes a novel VM system called MedusaVM to scale VM system to many cores. To this end, MedusaVM partitions the global virtual memory space and page table tree in a memory-efficient way, eliminating performance interference and lock contention between cores. Moreover, MedusaVM also provides a traditional shared memory interface for multithreaded applications. Our prototype system is implemented based on Linux kernel 4.4.0 and glibc 2.23. Experimental results evaluated on a 32-core machine demonstrate that MedusaVM scales much better than Linux kernel and uses 22 × less memory compared with the state-of-art approach. For microbenchmarks experiments, MedusaVM achieves nearly linear performance speedup. In multithreaded applications Metis and Psearchy, MedusaVM also significantly outperforms Linux kernel by up to a factor of 2.5 ×.