multi-core performance downgrade after switching "XR API" from Legacy to OVRPlugin OpenXR
Hello,
Recently we upgraded our engine to the latest Unreal 4.27 (source version, Meta branch) and Since the "Legacy" mode was gone, we have to switch to "OVRPlugin OpenXR". We noticed a performance downgrade probably due to this XR API change. The GameThread and RenderingThread have a lot more stall time waiting for each other (Acting like a single core) instead of running tasks in parallel.
I will attach some comparison graphs we collected from "Unreal Insight" and "Meta Performance Analyzer" below.
XR API: OVRPlugin+OpenVR
Unreal Insight-OVR Plugin+OpenXR
Performance Analyzer - OVR Plugin+OpenXR
XR API: Legacy
Unreal Insight-Legacy XR APIPerformance Analyzer - Legacy XR API
Wondering if anyone encountered such issue in 4.27. We really wish the new features came with V53 could help us but right now this issue is preventing us from switching to the latest version of the engine.
Thanks