"RenderQuery Result" What is it?
This is under Render Thread, FDrawscenecommand, RenderViewFamily, InitViews, View Visibility, Occlusion Cull, Fetch Visibility for primitives, and there it is "RenderQuery Result" and it's costing me 8ms.
What is it, and how do I go about optimizing the problem? My scene is fairly simple and consists of a small landscape with a material and grass as Foliage, I assume it has something to do with the grass.
HZBOcclusion is turned off, when enabled my FPS/GPU performance is reduced but DRAW no longer matches GPU times. GPU bottleneck instead?
[Specs i7 4790k, 16gb RAM, FuryX]
Did you ever find a solution? I have a similar issue with my game on lower end PCs, RenderQuery Result is costing a wopping 28-30ms.
answered Nov 08 '17 at 07:01 PM
When you disable HZB occlusion, the engine falls back to the GPU occlusion query, which "renders“ the bounding box of each primitive in scene to the GPU pipeline to see how many pixels of the primitive will end up on the scene. If the pixel count is 0, the primitive is treated as occluded. There might be some stalls related to the queries.
HZB is GHZBOcclusion and the platform by this line bool bHZBOcclusion = (!IsOpenGLPlatform(GShaderPlatformForFeatureLevel[Scene->GetFeatureLevel()]) && GHZBOcclusion) || (GHZBOcclusion == 2); in the function static int32 OcclusionCull(FRHICommandListImmediate& RHICmdList, const FScene* Scene, FViewInfo& View) located in SceneVisibility.cpp
For more information on GPU occlusion, you can check out this page http://developer.download.nvidia.com/books/HTML/gpugems/gpugems_ch29.html
answered Jan 24 '18 at 09:34 AM
RenderQuery Result is when the render thread stalls waiting for the GPU to finish the Occlusion Query, and return the results to the render thread, so that it knows what to render.
At the same time, the game thread is stalled waiting for the render thread.
This can be turned on or off with the console command
0 - off 1 - on
answered Dec 12 '18 at 06:48 PM
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