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Cycles denoise tile display on Windows 10 after recent change
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System Information
Operating system: Windows-10-10.0.17134 64 Bits
Graphics card: GeForce GTX 1060/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 419.17

Blender Version
Broken: version: 2.80 (sub 74), branch: master (modified), commit date: 2019-06-19 13:06, hash: rB72690bbeca85
Worked: Builds made yesterday.

Short description of error
Based on one simple benchmark it previously looked like there was a performance regression but after more extensive testing that appears not to be the case.

At least on Windows 10 / Nvidia 1060, when rendering in Cycles normal tiled mode with denoising on, all tiles which have completed rendering show as rendering (orange tile corners) while they are waiting for the availability of adjacent tile data.

Exact steps for others to reproduce the error
Open the attached

or simply switch to Cycles and enable de-noise. Hit F12.
In progress render looks like:



Event Timeline

Brecht Van Lommel (brecht) triaged this task as Needs Information from User priority.

What is the effect on GPU rendering only, without CPU?

Gavin Scott (Zoot) added a comment.EditedWed, Jun 19, 4:22 PM

Trying CPU only vs. GPU only, CPU is now 1:49 where GPU is 1:57 (GPU has never been slower than CPU before). In the new build. I overwrote yesterday's build after doing the first benchmark as I wasn't expecting problems.

Also, what happens without denoising enabled?

Looks like denoise is a major part of the issue.

Turning off denoise eliminates the border tile mark issue.

CPU only without denoise drops from 1:49 to 0:57
GPU only without denoise drops from 1:57 to 0:30 (!)
CPU+GPU without denoise drops from 1:07 to 0:25.

I tested a production scene of mine with todays build and the build from the day before yesterday.
Build: e73647bf5b44 (today)
GPU+CPU with denoise: 9:23
GPU+CPU without denoise: 8:43

Build: 12da679fa094 (17.06.2019)
GPU+CPU with denoise: 10:02
GPU+CPU without denoise: 9:36

So in my tests the todays build renders 6,9% faster with denoise on and 9,5% faster without denoise.
The difference between denoise on and off is about 40sec in the todays build.
The difference between denoise on and off is about 26sec in the build from the 17.06.2019.
Visual in the renderview there is one difference with the renderbuckets. If you have denoise on the buckets are also shown and disapear after the bucket is denoised. So a better visual feedback.
From may side no complaints.

My computer specs are:
Windows 10 Pro
Geforce GTX 1080 Ti
AMD Threadripper 1950X 16Cores 64GB RAM

Brecht Van Lommel (brecht) raised the priority of this task from Needs Information from User to Waiting for Developer to Reproduce.
Gavin Scott (Zoot) renamed this task from Cycles performance and tile display on Windows 10 after recent change to Cycles denoise tile display on Windows 10 after recent change.

Ok, thanks to Ray's secret build stash I was able to get a build from a couple of days ago and do a proper test with my quick benchmark file, and the upshot is that the recent changes had absolutely no effect on performance in Cycles for this simple scene on my system here.

I also rendered the standard BMW test scene and it did show a significant improvement with the new changes. I tried to render the Classroom benchmark but the version I have is incompatible with 2.80 (all the chair instances get deleted when you open it etc.)

So I apologize for the false alarm on the performance regression.

The issue of the queued up denoise tiles remains, and is confusing because you can't tell if a tile is still actually rendering or simply waiting for its data dependency on adjacent tile data to be fulfilled. I suppose it's not terrible the way it is now, it was just a bit surprising to see. I think it still makes more sense to only highlight the tile when the task is actually ready to run.

I don't suppose we could color the tile corners differently for render tasks and denoise tasks? Like, have green corners for denoise vs. the orange render ones? That would be super cool.

Just for completeness, here's the result of the performance tests. There are two runs for each test for each Blender version.

Old: 2.80 (sub 74), branch: HEAD, commit date: 2019-06-17 18:32, hash: rB28b06b6a05f7
New: 2.80 (sub 74), branch: master, commit date: 2019-06-19 13:06, hash: rB72690bbeca85

the tests were all with the attached file and show no significant change between versions, apart from the last two which were using the BMW scene from the benchmark suite.

Test			Old 1	Old 2	New 1	New 2
GPU + Denoise		1:56.66	1:55.94	1:54.87	1:55.36
GPU			0:29.36	0:29.45	0:29.28	0:29.19
CPU + GPU + Denoise	1:09.21	1:07.98	1:07:43	1:08.53
CPU + GPU		0:23.36	0:24.96	0:24.56	0:24.65
CPU + Denoise		1:50.94	1:47.32	1:45.92	1:44.70
CPU 			0:56.36	0:56.76	0:58.12	0:56.41

BMW CPU+GPU		2:42.27		2:04.53	
BMW GPU			3:05.96		2:19.02
Gavin Scott (Zoot) added a comment.EditedSat, Jun 22, 12:49 AM

If you setup Cycles to do a 10,000x10,000 pixel render with 8x8 tiles, then pretty soon things go wrong (with the render view) when the number of active tiles becomes very large due to all the pending denoise operations. It starts displaying a semi-random assortment of the active tiles, some blink on and off, etc. Example:

Edit: the render of 1.5 million tiles finished in about 90 minutes and as far as I can see all the denoise tasks completed successfully.