Vulkan 1.0.9 Specification Released

[phoronix]

Phoronix: Vulkan 1.0.9 Specification Released

It seems the weekly Vulkan specification updates will be continuing for some amount of time...

http://www.phoronix.com/scan.php?pag...1.0.9-Released

[theriddick]

I hear the Shader performance with Vulkan is %30-40 slower then DX12 and not easy to program for. I do hope they address those issues at some point.

[bridgman]

Where are you hearing this ?

Not disagreeing necessarily, but "Vulkan's" shader performance isn't likely to be slower (ie something about the spec that inherently makes compiled shader code run that much more slowly), just "a specific Vulkan implementation's" performance.

[Azpegath]

I'd like to get references on that as well.

[theriddick]

Just read it on some steam game and community forums that Vulkan had these issues with its shader system which is why DX12 is still attractive atm.

Sorry there is no articles on it but am sure we will hear more about any issues in the coming months once some developers actually try to make their games with Vulkan API (so far not much activity on that front).

[Shevchen]

Well, having a real source might help to get to the root of this "problem" (if it even exists) - but as I viewed and read to a bit of Dev feedback to Vulkan, its more about the learning curve to properly implement all connecting bits. We had about... lets say 20 years of more or less "easy going" DirectX programming that was rather far away from the silicon and the game devs are also not people like driver specialists who know everything about the underlying hardware - so of course there will be a gap at the beginning. That DirectX performs better here and there doesn't mean that there is a "bug" or "missing optimization" (of course still it can), but I have a gut feeling, thats its more about the proper implementation and deeper understanding of the API. You can break quite some things (or slow them down) and it takes time to get into all that stuff, so proper documentation is worth the time. (As always)

I already have a game (Mechwarrior online) running under Wine (with gallium nine) that is faster under the DX9 "translation" than under Windows 10 DX11 - and the difference is about 100% - 150% more performance (DX9 Windows native vs Linux for Linux being faster - AMD Radeon HD 7970)
What I want to say with it: We have still a LOT of headroom to the max. possible performance increase, if this "little" hack yield so much more performance. With proper Vulkan support... oh man, I can only dream.

[theriddick]

I believe 'Vulkans Shader system is a mess" is the exact about words from one developer. I will try and dig it up but this was quite some time ago and will likely take me a couple days of digging to find it because like I said, not many are making Vulkan support yet.

[log0]

I believe 'Vulkans Shader system is a mess" is the exact about words from one developer. I will try and dig it up but this was quite some time ago and will likely take me a couple days of digging to find it because like I said, not many are making Vulkan support yet.

Could this be the source? https://forums.inovaestudios.com/t/t...-question/3174

Reddit: https://www.reddit.com/r/vulkan/comm...r_ecosystem_a/

Seems like the guy is using talos performance numbers to argue against vulkan (totally ignoring talos devs comments), which makes him look rather silly.

[theriddick]

Could be some of them, think I found some comments on steam also about the issues with shader performance and coding in Vulkan. They were talking about how DX12 is allot easier to work with in that regard but perhaps they were wrong somehow.


PS. Having issues loading the forum now and again..

[smitty3268]

Where are you hearing this ?

Not disagreeing necessarily, but "Vulkan's" shader performance isn't likely to be slower (ie something about the spec that inherently makes compiled shader code run that much more slowly), just "a specific Vulkan implementation's" performance.

I'm pretty sure he was referring to this: https://forums.inovaestudios.com/t/t...-question/3174

The dev there seems to be making some assumptions that I'm not sure are necessarily correct - namely, pointing to the Talos Principle benchmarks and claiming that the reason it's 30% slower than DX12 is clearly because of the shader compiler not being good enough. And then later points to this bug and says that they don't have a way to generate optimized spir-v shaders, which is a problem: https://github.com/LunarG/LunarGLASS/issues/5

He seems to think that Epic, Valve, etc. will be coming up with something to optimize their own shaders but that his company isn't big enough to do so and needs something standard provided to him, and that it's missing from Vulkan.

I'm not sure how to really evaluate that - is the llvm thing in that bug what he should be using? Is he just supposed to rely entirely on the drivers to optimize it all? Is the shader issue even a problem on Talos rather than other porting issues not being done yet?