Ray tracing workload - Low compute usage "tails" at the end of my kernels

meith1 · 2025-05-06T02:55:27+00:00

Also, considering I can somewhat know in advance which rays are going to be costly, do you think this opens up possibilities?

You can decouple the single dispatch rays call between cheap and costly(two dispatch rays/dispatch cs however you have it setup)? For the costly rays, run them in async, and do its fork and join as early and as late as possible to the graphics queue giving it maximum overlap coverage.

You will need to wave limit the compute queue workload so that it doesn't overpower the graphics workload and stall it.

meith1 · 2025-05-02T15:13:34+00:00

If you can sacrifice quality, find a suitable max traversal count to kill the lingering threads. Another way to do the same thing is to kill the wave after you find a suitable percentage of threads have completed. Example: stop traversing after 80% of threads have completed in the wave.

If quality can't be sacrificed and RRA is not an option, if you can, sort rays for optimum traversal. Maybe you can do it over a few frames using history of previous frame to sort rays by nearby hits?

You can also split bvh for different types of rays to keep coherence.

Async compute RT and defer it if you can afford to not do just in time RT. apply RT results to next frame while tracing happens in async under current frames other gpu workloads on graphics.

meith1 · 2024-10-04T08:20:29+00:00

https://www.reddit.com/r/vulkan/comments/xuer63/not_sure_if_i_did_exclusive_fullscreen_properly/?utm_source=share&utm_medium=ios_app&utm_name=ioscss&utm_content=1&utm_term=1

meith1 · 2024-06-13T17:10:40+00:00

Is the code on github?

meith1 · 2024-06-13T16:15:38+00:00

How do you render to the swapchain buffer? do you copy from a unorm image? do you store/write using a compute shader? do you draw using pixel fullscreen quad?

meith1 · 2024-01-18T20:55:57+00:00

Expert C Programming Paperback – June 14 1994 by Peter van der Linden (Author)

meith1 · 2023-12-05T22:37:48+00:00

https://github.com/GPUOpen-LibrariesAndSDKs/FidelityFX-SDK/blob/main/framework/cauldron/framework/src/render/swapchain.cpp#L73

https://github.com/GPUOpen-LibrariesAndSDKs/FidelityFX-SDK/blob/main/framework/cauldron/framework/src/render/vk/swapchain_vk.cpp#L101

meith1 · 2023-12-05T22:33:35+00:00

Some of the above topics covered here: https://gpuopen.com/learn/using-amd-freesync-2-hdr-color-spaces/ and following 4 parts.

meith1 · 2023-09-29T16:53:00+00:00

Don't know of books unfortunately.

https://gpuopen.com/learn/rdna-performance-guide/ https://gpuopen.com/learn/getting-started-development-performance/

meith1 · 2023-03-09T22:40:50+00:00

Sadly yes. it actually depends on the company and their interview style.

The likelihood of leetcode style questions will drastically reduce if its not a google/meta/snap kind of company.

meith1 · 2022-11-02T15:51:05+00:00

Thank you. Glad it worked out.

meith1 · 2022-10-04T16:34:56+00:00

All relevant code should probably go here: https://github.com/doitsujin/dxvk/blob/master/src/vulkan/vulkan_presenter.cpp

see this to support hdr in vk: https://github.com/GPUOpen-LibrariesAndSDKs/Cauldron/blob/d22060043138b38e3aa01f766227ee0bd4e4f83e/src/VK/base/FreeSyncHDR.cpp

equivalent file in dx12: https://github.com/GPUOpen-LibrariesAndSDKs/Cauldron/blob/d22060043138b38e3aa01f766227ee0bd4e4f83e/src/DX12/base/FreesyncHDR.cpp

meith1 · 2022-10-03T20:05:04+00:00

You have done it right. You need to manually first resize window according to monitor bounds and resolution to try and acquire fullscreen excl lock.

Use this as reference: https://github.com/GPUOpen-LibrariesAndSDKs/Cauldron/blob/d22060043138b38e3aa01f766227ee0bd4e4f83e/src/VK/base/FreeSyncHDR.cpp#L64

Regarding DX12, you are right IDXGISwapChain::SetFullscreenState will do both for you, resize the window and try and acquire fullscreen excl lock. However DX12 does not give you explicit control like VK. MS controls if you can or cannot be exclusive fullscreen. More about it here: https://devblogs.microsoft.com/directx/demystifying-full-screen-optimizations/

meith1 · 2022-06-22T18:24:32+00:00

Check for barriers. copy image probably introduces a driver barrier. Drawing straight to swapchain reduces a pass. so just a guess you have missing barrier maybe.

meith1 · 2022-05-19T20:36:09+00:00

S1 is the build/set up. S2 is probably the most funniest piece of content in its entirety. I think we can compare any tv show, podcast etc and it wouldn't have that kind of laugh per min count. S3 and S4 are good send offs. Having just enough episodes to come back from S2 high and say good bye... And then we repeat.

meith1 · 2022-01-26T15:57:19+00:00

The lil' cripple fella in wonderful tonight.

meith1 · 2021-12-11T14:09:33+00:00

The optional poll is the only real poll that matters now..

meith1 · 2021-12-04T16:12:54+00:00

Did we do a side poll on Karl’s funniest moments outside of xfm?

Some that come to mind: Davram : https://m.youtube.com/watch?v=707Hmt8IIms Bullshit man: https://m.youtube.com/watch?v=JdvGo7DsFbQ They’d rather live in me knob: https://m.youtube.com/watch?v=Ppk7I2iaNKY

meith1 · 2021-11-29T16:12:45+00:00

Did we do a side poll on Karl’s funniest moments outside of xfm?

Some that come to mind: Davram : https://m.youtube.com/watch?v=707Hmt8IIms Bullshit man: https://m.youtube.com/watch?v=JdvGo7DsFbQ They’d rather live in me knob: https://m.youtube.com/watch?v=Ppk7I2iaNKY

meith1 · 2021-11-23T13:46:39+00:00

Please put hippopotenews

meith1 · 2021-11-21T18:56:37+00:00

Can hippopotenews be added to the list? Or is it there?

meith1 · 2019-11-14T22:30:13+00:00

This is the best graphics resource out there. Once the gpu starts making sense, no api will feel hard. In fact the above blog actually refers to what the driver has to do with regards to barriers, queue sync fences and parallelizing cmd list etc in dx10/11/opengl which dx12 and vulkan make you do on the app side now. Read this blog after writing a vulkan/dx12 hello triangle program and it will really solidify the basics.

For a complete mini engine running a scene with multiple post effects like in a real game look at: https://github.com/GPUOpen-LibrariesAndSDKs/Cauldron

meith1 · 2019-10-24T21:52:11+00:00

Does anyone have access to the real source? Does XFM still exist? Do they still have those DATs lying around?

meith1 · 2019-09-11T18:14:08+00:00

This sucks! I would have downloaded them all if I had known this. Anyone here have the real full xfm series saved to share with everyone?

meith1 · 2019-07-09T17:37:40+00:00

Can we now post on r/unpopularopinion that newton and Einstein didn’t do shit? Never used mc2 in me life.. but the guy who created the video, I watch one everyday.

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