Performance issues with Lavapipe in Windows (?)

[Adam Jackson]

My first suspicion would be to rule out window system interaction. If you
render to your own VkImage instead of to a swapchain, how fast can you go?

- ajax


On Tue, Apr 4, 2023 at 12:56 PM George Karpathios <gkarpa1 at gmail.com> wrote:

> Hi list, I hope all is well.
>
> I would like to ask if there are any known issues regarding the
> performance of Lavapipe in Windows 10.
>
> I'm trying to add support for Vulkan software rendering into a relatively
> large 3d modeling/rendering application, so I opted to try Mesa and
> Lavapipe. I built LLVM 16.0.0 and Mesa 23.0.1 using the documentation
> (thanks for that!). My environment is an 8-core Intel i7 (with an
> integrated iGPU) with 32GiB RAM, an nVidia RTX 3070 and Visual Studio
> 2019/MSVC.
>
> The build procedure seems to be ok (Release builds, proper linking with
> either MT or MD runtime libraries, proper DLL loading via VK_ICD_FILENAMES)
> but the performance I'm getting during runtime is very slow. It looks like
> it needs 1-1.5 seconds to render a virtually empty scene (think just a
> floor grid of lines)  and over 15-20 seconds for a frame of a few thousand
> vertices. The CPU utilisation also seems to be low, under 20-25%.
>
> I understand that the information I provide is probably vague, but at this
> point I just want to rule some probable causes out, like is there any
> version of LLVM or Mesa or combination of them that is known to have such
> issues? Maybe some build/installation configuration parameter or
> environment variable that is important in Windows specifically and I may
> have missed (I tried tweaking LP_NUM_THREADS but didn't change anything) ?
> Anything that could point me in the right direction is highly valuable &
> appreciated.
>
> Also probably worth noting is the fact that the vkcube(pp) demo from the
> Vulkan SDK seems to run ok with Lavapipe, but in this case I also notice
> (in task manager) a ~50% utilization of the integrated iGPU (why?). In the
> aforementioned larger application I don't notice any usage of the
> integrated iGPU.
>
> Any advice on what I could check/double check is more than welcome. Thank
> you in advance for your time.
>
> Best regards,
> George
>
>
>
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