Performance issues with Lavapipe in Windows (?)

Mike Blumenkrantz michael.blumenkrantz at
Fri Apr 7 14:34:38 UTC 2023

You can try deleting the lvp_find_inlinable_uniforms() call from
lvp_pipeline.c as a temporary workaround. I'll try something on my end to
make this less stupid.

On Fri, Apr 7, 2023 at 10:22 AM George Karpathios <gkarpa1 at> wrote:

> Awesome, thanks for the tip!
> Well now I indeed get *very* nice frame times. Great catch, thank you!
> But I don't see anything on the viewport, I guess due to the early return.
> How should I proceed?
> Best regards,
> George
> On Fri, Apr 7, 2023 at 4:56 PM Mike Blumenkrantz <
> michael.blumenkrantz at> wrote:
>> Looks like it's compiling a lot of shader variants.
>> You could try adding a return at the top of update_inline_shader_state()
>> to see if it's trying too hard to inline.
>> On Fri, Apr 7, 2023 at 9:53 AM George Karpathios <gkarpa1 at>
>> wrote:
>>> Hi again, thank you Adam & Marek for your feedback! I appreciate it.
>>> Unfortunately It's the same amount of time even if I skip the swapchain.
>>> I have profiled some seconds of the execution using Visual Studio's
>>> profiler (with the swapchain, normally) while panning an almost empty
>>> scene, and it's identifying a hotpath. I have uploaded 2 screenshots of the
>>> call tree at  if you'd like to check it
>>> out.
>>> Another thing I'd like to note is that by using Mesa 23.1-dev (instead
>>> of 23.0.1) I got a nice performance boost of ~2-3x. However it's still
>>> performing slower than what I'd expect on this system (right now it takes
>>> 60ms for 10 lines so I feel that something weird is still going on). Big
>>> congratulations on your tremendous work anyway.
>>> Best regards,
>>> George
>>> On Tue, Apr 4, 2023 at 9:24 PM Adam Jackson <ajax at> wrote:
>>>> 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>
>>>> 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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