Colton Lewis
Colton Lewis is a software engineer on the Google KVM Team. He draws on 9 years of professional experience and graduated with a Bachelor's Degree in Computer Engineering from the Missouri University of Science and Technology in 2016. He is passionate about operating systems, programming languages, books, piano, tabletop games, and weightlifting.
Session
KVM's current vPMU implementation on ARM traps and emulates the PMU in entirety. This is a significant cause of overhead for any use of performance monitoring capabilities inside a guest.
This talk will explain my work over the past several months to improve the matter. [1] Relying on modern ARM CPU features such as PMUv3 and FGT (fine grain traps), it becomes possible to selectively untrap the most common PMU registers and features to allow guests direct hardware access to cut the overhead and significantly improve performance. A more detailed explanation with some notable performance improvements can be found in my cover letter on the kvmarm mailing list.
[1] https://lore.kernel.org/kvmarm/20250602192702.2125115-1-coltonlewis@google.com/