Maniphest T60576

Cycles slow render start with GTX 2070
Closed, Resolved
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Assigned To
jan bauer (janb)
Authored By
jan bauer (janb)
Jan 16 2019, 9:20 PM
Tags
  • BF Blender
  • Cycles
Subscribers
Brecht Van Lommel (brecht)
Gavin Scott (Zoot)
jan bauer (janb)

Description

System Information
Operating system: Windows 10
Graphics card: RTX 2070

Blender Version
Broken: 8ba86020cc50 (but both 2.80 and 2.79 buildbots have the bug
Worked:

Short description of error
When rendering some scenes, Cycles takes more than 2 minutes to start the first tile. It happens often on the classroom scene, some scene are not hit by the bug (like bmw and barcelona)

Exact steps for others to reproduce the error
Open the classroom scene (from https://download.blender.org/demo/test/cycles_benchmark_20160228.zip) with latest buildbots and hit F12. Most of the time, only the first render has the bug, the following ones are ok. The bug is random, so sometime it starts directly.

Related Objects

Mentioned Here
rB8ba86020cc50: GP: Display Stroke for Fill Alt mode always

Event Timeline

jan bauer (janb) created this task.Jan 16 2019, 9:20 PM
Brecht Van Lommel (brecht) lowered the priority of this task from 90 to 30.Jan 17 2019, 4:08 PM
Brecht Van Lommel (brecht) added a subscriber: Brecht Van Lommel (brecht).

I can't reproduce the problem.

  • I assume you are using GPU rendering, and the problem does not happen with CPU rendering?
  • What shows in the render progress info text when it is stuck?
  • Has the problem always existed with this GPU, or did it work better before?
Brecht Van Lommel (brecht) renamed this task from regression - Cycles render very slow with latest buildbots to Cycles slow render start with GTX 2070.Jan 17 2019, 4:08 PM
Gavin Scott (Zoot) added a subscriber: Gavin Scott (Zoot).EditedJan 17 2019, 7:35 PM

I saw something like this today (on current 2.80 build, Windows 10, Nvidia 1060 6GB)) based on the scene in this discussion about CPU+GPU tile differences:

https://blenderartists.org/t/gpu-rendering-issue-tiles-rendering-different-colours/1142774/18

The .blend in that thread, when opened in 2.80 and hitting F12, sits for 90 seconds at Rendering progress 0% with no rendering progress messages having been displayed at the top of the screen. Stdout contained:

GPUFrameBuffer: framebuffer status GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT

So I wonder if this is a timeout talking to the GPU for some reason? The same .blend starts the render pre-processing immediately in 2.79 builds ('a' and recent but not current) and does not produce the GL_ message.

jan bauer (janb) added a comment.Jan 17 2019, 8:01 PM
In T60576#601582, @Brecht Van Lommel (brecht) wrote:

I can't reproduce the problem.

  • I assume you are using GPU rendering, and the problem does not happen with CPU rendering?

I didn't test cpu rendering, it happens randomly also with GPU. I tried 10 times with CPU, it always started directly.

  • What shows in the render progress info text when it is stuck?

it says "updating shaders"

  • Has the problem always existed with this GPU, or did it work better before?

it's a new problem, it never happens on 2.79b, and I think something like november, the bug wasn't there (I remember benchmarking classroom around that time, but don't have a build anymore and it was with another GPU.)

Brecht Van Lommel (brecht) added a comment.Jan 21 2019, 5:15 PM

Does it still happen with the latest builds?

Are you using a Threadripper or Ryzen CPU? We recently fixed an issue a bit like this for them.

jan bauer (janb) added a comment.Jan 27 2019, 7:56 PM

just tested with todays build, the bug is still there when using cuda rendering and a i7 7700K.

jan bauer (janb) changed the task status from Unknown Status to Resolved.Feb 26 2019, 8:39 PM
jan bauer (janb) claimed this task.

the bug is gone since some weeks now, don't know why, but resolved.