Future-Proofing Virtual Memory

Date: Sep 08, 2023
Time: September, 11st 3:00pm-4:30pm
Location: the lecture hall on the forth floor

Speaker: C. Mohan, Distinguished Professor of Science (Hong Kong Baptist University, China),Distinguished Visiting Professor (Tsinghua University, China),Retired IBM Fellow (IBM Research, USA) 

Abstract: This talk addresses emerging challenges to future-proof virtual memory in post-Moore servers. I will introduce Midgard, a novel VM implementation that exposes a global but sparse intermediate address space in the coherent cache hierarchy while maintaining backward compatibility with existing commodity UNIX-based OSes. Midgard eliminates TLBs by offering a direct translation in hardware from existing OS VM software abstractions and performs page-level translations only when accessing physical memory or I/O. In contrast to page-based VM, Midgard’s overall address translation overhead decreases with an increase in cache hierarchy capacity. I will also go over system-level implications (both hardware and software) of implementing Midgard and usecases of scalable virtual memory.
Speaker's bio: Babak is a Professor and the founder of EcoCloud at EPFL. His contributions include the first NUMA multiprocessors by Sun, memory streaming integrated in IBM BlueGene and ARM cores, and performance evaluation methodologies used by AMD, HP and Google PerfKit. He has shown that memory consistency models are neither necessary nor sufficient to achieve high performance in servers. His work on workload-optimized server processors laid the foundation for the first generation of Cavium ARM server CPUs, ThunderX. He is a recipient of an Alfred P. Sloan Research Fellowship, and a fellow of ACM and IEEE.