Optimizing VM Performance Monitoring on Commodity x86 Platforms With PMU Passthrough
Journal
IEEE Transactions on Cloud Computing
Start Page
1
End Page
13
ISSN
2168-7161
2372-0018
Date Issued
2025-11-17
Author(s)
Abstract
Modern processors expose hardware performance monitoring capabilities through Performance Monitoring Units (PMUs). Profiling tools leverage these PMU facilities to analyze program execution. As the computation is increasingly shifting to virtual machines (VMs), commodity hypervisors like KVM have implemented virtual PMUs (vPMUs) to expose these capabilities to VMs. However, we found that KVM's current vPMU implementation introduces substantial overhead, leading to inaccurate measurements. This overhead stems from frequent VM exits caused by PMU access and sampling interrupts, as well as the complexity of emulation. To address this, we develop Direct vPMU (D-vPMU), a novel set of passthrough mechanisms for Intel x86 platforms running KVM. D-vPMU enables VMs to access the physical PMU and handle interrupts directly, thereby eliminating the virtualization overhead that currently plagues vPMU solutions. D-vPMU delivers better profiling accuracy and performance while strictly maintaining the security and isolation boundaries between guest and host PMU contexts.
Publisher
Institute of Electrical and Electronics Engineers Inc.
Type
journal article