Regression: Slow renders on Intel Mac / AMD GPU #120006

New Issue

Werner · 2024-03-28T09:42:29+01:00

Werner commented

2024-03-28 09:42:29 +01:00

System Information
Operating system: MacOs 14.4.1
Graphics card: AMD Radeon Pro Vega II 32 GB (Metal 3)

Blender Version
Broken: 4.2.0 Alpha (SHA 05c1abe59c, 19 Apr 01:49)
Worked: 4.0.2, 4.1.1

Short description of error

Any cycles GPU render in 4.2 takes a factor 0f 2-3 more time compared to versions 3.6.x-4.0.2 and 4.1.1 (which are all consistent).

Note for people reading the outdated comments. The original report was for a performance regression in Blender 4.1.0. This was fixed in 4.1.1, but 4.2 still has a regression.

**System Information** Operating system: MacOs 14.4.1 Graphics card: AMD Radeon Pro Vega II 32 GB (Metal 3) **Blender Version** Broken: 4.2.0 Alpha (SHA `05c1abe59c`, 19 Apr 01:49) Worked: 4.0.2, 4.1.1 **Short description of error** Any cycles GPU render in 4.2 takes a factor 0f 2-3 more time compared to versions 3.6.x-4.0.2 and 4.1.1 (which are all consistent). --- Note for people reading the outdated comments. The original report was for a performance regression in Blender 4.1.0. This was fixed in 4.1.1, but 4.2 still has a regression.

Werner added the

labels 2024-03-28 09:42:30 +01:00

Alaska commented

2024-03-28 10:05:40 +01:00

Outdated comment

I can not reproduce the slowdown on a M1 Pro with Metal GPU rendering when comparing Blender 4.0.2 to 4.1.

This is likely another performance regression specific to AMD GPUs with the Cycles Metal backend. @iss Do you have the right hardware to test this (A AMD GPU on macOS)? Or know the right person to contact to test this?

<details> <summary>Outdated comment</summary> I can not reproduce the slowdown on a M1 Pro with Metal GPU rendering when comparing Blender 4.0.2 to 4.1. This is likely another performance regression specific to AMD GPUs with the Cycles Metal backend. @iss Do you have the right hardware to test this (A AMD GPU on macOS)? Or know the right person to contact to test this? </details>

Richard Antalik commented

2024-03-28 18:50:50 +01:00

Outdated comment

Tested with junk shop: 4.0: 28.82s 4.1: 43.62s

So can confirm regression MacOS 14.0, 5700XT

<details> <summary>Outdated comment</summary> Tested with junk shop: 4.0: 28.82s 4.1: 43.62s So can confirm regression MacOS 14.0, 5700XT </details>

Richard Antalik changed title from ~~Bad render times using Blender 4.1 on Intel Mac Pro 2019 / AMD Radeon Vega II~~ to Regression: Slow renders on Intel Mac / AMD GPU

2024-03-28 18:52:05 +01:00

Richard Antalik added

and removed

labels 2024-03-28 18:52:22 +01:00

Pratik Borhade commented

2024-03-29 03:30:33 +01:00

cc @Michael-Jones

Alaska commented

2024-03-29 06:18:54 +01:00

CC @brecht as well because you've done previous work on working around these performance regressions. And just to keep you informed on the Metal AMD GPU issues.

Werner commented

2024-03-29 10:21:40 +01:00

Outdated comment

I investigated the problem somewhat further by compiling Blender 4.1:

Downloaded the source-code from github
git clone https://projects.blender.org/blender/blender.git
git checkout tags/v4.1.0
make update
mkdir build
cd build
ccmake ..
in cmake: configure (several times) + generate
make -j22
make install

Variant 1:
Compiled with CommandLineTools 15.3

Variant 2:
Compiled with CommandLineTools 14.3.1
(In order to do so, I had to remove the "-ld_classic" link flag in "build_files/cmake/platform/platform_apple.cmake")

Tests with junk-shop
4.0 from Blender download page: 38.81 s
4.1 from Blender download page: 62.50 s
4.1 Variant 1: 61.88 s
4.1 Variant 2: 37.44 s

Conclusion:
The performance drop is related to the 15.3 SDK in MacOS.
When compiling with 14.3.1, 4.1 shows the same performance as 4.0!

Hope this helps somewhat...

<details> <summary>Outdated comment</summary> I investigated the problem somewhat further by compiling Blender 4.1: - Downloaded the source-code from github - git clone https://projects.blender.org/blender/blender.git - git checkout tags/v4.1.0 - make update - mkdir build - cd build - ccmake .. - in cmake: configure (several times) + generate - make -j22 - make install Variant 1: Compiled with CommandLineTools 15.3 Variant 2: Compiled with CommandLineTools 14.3.1 (In order to do so, I had to remove the "-ld_classic" link flag in "build_files/cmake/platform/platform_apple.cmake") Tests with junk-shop 4.0 from Blender download page: 38.81 s 4.1 from Blender download page: 62.50 s 4.1 Variant 1: 61.88 s 4.1 Variant 2: 37.44 s Conclusion: The performance drop is related to the 15.3 SDK in MacOS. When compiling with 14.3.1, 4.1 shows the same performance as 4.0! Hope this helps somewhat... </details>

Werner commented

2024-03-29 10:31:36 +01:00

Outdated comment

Forgot to mention:
The first time you start up and render, the kernels have to be compiled/loaded.

I noticed with the official release of 4.1 and 4.1 - Variant 1, see above), this takes only about 10 seconds, while for 4.0 or 4.1 - Variant 2 it takes much longer (about 180 seconds).

Could it be that the kernels are not actually compiled correctly?
However I did not see any warnings or errors.
Does it somehow falls back to OpenCl? The GPU load is nearly the same for all variants...

Best regards

<details> <summary>Outdated comment</summary> Forgot to mention: The first time you start up and render, the kernels have to be compiled/loaded. I noticed with the official release of 4.1 and 4.1 - Variant 1, see above), this takes only about 10 seconds, while for 4.0 or 4.1 - Variant 2 it takes much longer (about 180 seconds). Could it be that the kernels are not actually compiled correctly? However I did not see any warnings or errors. Does it somehow falls back to OpenCl? The GPU load is nearly the same for all variants... Best regards </details>

Alaska commented

2024-04-07 01:56:55 +02:00

Outdated comment

@camot does this version of Blender resolve the performance issue? #120126 (comment)

If you would prefer to build it yourself, then please switch back to CommandLineTools 15.3 and apply this code change to Blender 4.1: !120299

I bring this up because in Blender 4.1, MetalRT is accidentally enabled on all macOS 14+ AMD GPU macs. But I don't think the Vega II or 5700XT properly support MetalRT, and might be experiencing a performance regression because of it.

!120299 fixes this issue by only enable MetalRT on the devices it's supposed to be enabled on and it might resolve the performance issue you are experiencing in the process.

You do mention that dropped to CommandLineTools 14.3.1 fixes the performance issue, and I believe the code that activates MetalRT is skipped with older compilers, hence why I think this might help. But I might be wrong, I'm not that familiar in this area .

<details> <summary>Outdated comment</summary> @camot does this version of Blender resolve the performance issue? https://projects.blender.org/blender/blender/issues/120126#issuecomment-1161734 If you would prefer to build it yourself, then please switch back to CommandLineTools 15.3 and apply this code change to Blender 4.1: !120299 --- I bring this up because in Blender 4.1, MetalRT is accidentally enabled on all macOS 14+ AMD GPU macs. But I don't think the Vega II or 5700XT properly support MetalRT, and might be experiencing a performance regression because of it. !120299 fixes this issue by only enable MetalRT on the devices it's supposed to be enabled on and it might resolve the performance issue you are experiencing in the process. --- You do mention that dropped to CommandLineTools 14.3.1 fixes the performance issue, and I believe the code that activates MetalRT is skipped with older compilers, hence why I think this might help. But I might be wrong, I'm not that familiar in this area . </details>

Werner commented

2024-04-07 18:18:27 +02:00

Outdated comment

@Alaska I did as you suggested: info.use_metalrt_by_default = false; + compiled with 15.3

I can confirm that this indded resolves the render performance issue.
junk shop takes 37.74 s, the same as with 4.0

It would be nice if one could disable metalRT through the settings.

Thank you very much to resolve the issue!

Best regards!

<details> <summary>Outdated comment</summary> @Alaska I did as you suggested: info.use_metalrt_by_default = false; + compiled with 15.3 I can confirm that this indded resolves the render performance issue. junk shop takes 37.74 s, the same as with 4.0 It would be nice if one could disable metalRT through the settings. Thank you very much to resolve the issue! Best regards! </details>

Alaska commented

2024-04-08 01:16:46 +02:00

Outdated comment

It would be nice if one could disable metalRT through the settings.

You can disable MetalRT in Blender settings if your GPU is officially support by MetalRT. However I believe your GPU isn't officially support, and so the setting doesn't show up.

The fact MetalRT was being enabled on your GPU when it wasn't officially supported was a mistake in the code, and seems to be the cause for the performance issues you are having.

<details> <summary>Outdated comment</summary> > It would be nice if one could disable metalRT through the settings. You can disable MetalRT in Blender settings if your GPU is officially support by MetalRT. However I believe your GPU isn't officially support, and so the setting doesn't show up. The fact MetalRT was being enabled on your GPU when it wasn't officially supported was a mistake in the code, and seems to be the cause for the performance issues you are having. </details>

Alaska referenced this issue

2024-04-08 01:19:26 +02:00

Cycles: Properly default to Metal-RT off unless GPU is a M3 or newer #120299

Sergey Sharybin referenced this issue

2024-04-09 16:20:25 +02:00

4.1: Candidates for corrective releases #119631

Sergey Sharybin commented

2024-04-09 16:23:12 +02:00

I've landed a fix from Alaska to the main branch, and the fix should be included into 4.1.1.
Unfortunately, I can not fully confirm the fix on the current main branch, as the render result is just black, no matter whether HW RT is enabled or not. There is still some issue to be fixed there. It might be something unrelated to the root cause of this issue in 4.1.0, but I am not fully confident of considering this report fully resolved before we have confirmation that fix will also work for 4.2.

I've landed a fix from Alaska to the main branch, and the fix should be included into 4.1.1. Unfortunately, I can not fully confirm the fix on the current main branch, as the render result is just black, no matter whether HW RT is enabled or not. There is still some issue to be fixed there. It might be something unrelated to the root cause of this issue in 4.1.0, but I am not fully confident of considering this report fully resolved before we have confirmation that fix will also work for 4.2.

Alaska commented

2024-04-19 14:30:38 +02:00

Blender 4.1.1 is now out. Can @camot and/or @iss please test Blender 4.1.1 to confirm if the issue has been fixed? https://www.blender.org/download/

Can you also test the latest version of Blender 4.2 and let us know if that has a performance regression? (The rendering issue in 4.2 Sergey mentionied above has also been fixed) https://builder.blender.org/download/daily/

I am reducing the priority of this bug down to normal as prior testing points to this issue being fixed. I just want confirmation before closing the report.

Blender 4.1.1 is now out. Can @camot and/or @iss please test Blender 4.1.1 to confirm if the issue has been fixed? https://www.blender.org/download/ Can you also test the latest version of Blender 4.2 and let us know if that has a performance regression? (The rendering issue in 4.2 Sergey mentionied above has also been fixed) https://builder.blender.org/download/daily/ --- I am reducing the priority of this bug down to normal as prior testing points to this issue being fixed. I just want confirmation before closing the report.

Alaska added

and removed

labels 2024-04-19 14:30:48 +02:00

Werner commented

2024-04-19 17:56:24 +02:00

@Alaska:
Can confirm 4.1.1 fixes the issue!
junk shop takes 37.47 s, the same as with 4.0!
So all good for 4.1.1

However in 4.2.0 Alpha (SHA 05c1abe59c, 19 Apr 01:49, Intel):
junk shop takes 84 s (average of 3 runs, all within 0.3 s)!
So it has definitively a performance regression!

Best regards

@Alaska: Can confirm 4.1.1 fixes the issue! junk shop takes 37.47 s, the same as with 4.0! So all good for 4.1.1 However in 4.2.0 Alpha (SHA 05c1abe59c95, 19 Apr 01:49, Intel): junk shop takes 84 s (average of 3 runs, all within 0.3 s)! So it has definitively a performance regression! Best regards

Alaska commented

2024-04-20 06:10:42 +02:00

Increasing the priority again, and adjusting the report description to reflect the new information.

Alaska added

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labels 2024-04-20 06:10:53 +02:00

Alaska added the

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