Gemfire: Enabling hyper-threading on bare metal

Products

• VMware Tanzu Gemfire

Issue/Introduction

The Gemfire documentation recommends "Always enable hyper-threading" in the section for improving performance on vSphere. Is this general recommendation also applicable to bare metal?

Environment

All supported Gemfire versions.

Resolution

The recommendation for VMware GemFire differs between virtualized environments and bare metal because of how resource scheduling and context switching work in those two scenarios.

On bare metal, hyper-threading would cause more resource contention arising from multiple Gemfire threads fighting over physical resources. The increased cost of context switching outweighs any performance benefits from hyper-threading. In the case of a virtualized environment, the hypervisor handles the mapping between vCPUs and physical CPUs making scheduling very efficient.  Note that vSphere is highly optimized for hyper-threading.

If you want the absolute lowest latency and most predictable performance for Gemfire on bare metal, disable Hyper-threading in the BIOS.