High CPU on NSX-T Bare Metal Edge

Products

• VMware NSX

Issue/Introduction

NSX-T Bare Metal Edge reports high CPU usage

Environment

VMware NSX-T Data Center

Resolution

By default, half of the available cores on the Bare Metal Edge are allocated for polling threads.
Each of these cores will report 100% CPU usage even if there is no traffic processed.
This is because the fastpath threads, dp-fp, are running in polling mode.
This configuration is exclusive to Bare Metal Edges because the physical resources are dedicated and not shared.
These threads are actively monitoring for new packets on hardware queues which avoids the requirement for context switching, ensuring optimum performance and low latency.
A Bare Metal Edge will therefore observe at least 50% CPU usage as a baseline.

To review the actual CPU used to process packets, the following admin cli command can be used

edge> get dataplane cpu usage