DX12 Shader Profiler Warp count

In the summary of the shader profiler there is a column “#warp”. One of my pixel shaders have a meager 3 there. Unsurprisingly it suffers from lots of unused warp slots and many stalls because of long scoreboard. In the details it tells me “3D Attribute Size limiter 3 - 29”. I might have been wrongly assumed that this is caused by a quite high number of inputs that this shader gets. I started to reduce them but it does not have changed anything so far. Is there some information available how this value is actually calculated? Do I just need to remove more shader inputs to see an effect?

Not sure if this matters here but this pixel shader is part of a pipeline object that has a hull and domain shader, too.

Thank you for using Nsight Graphics Shader Profiler and I’m sorry you ran into this issue. I’ll contact the engineering manager for the Nsight Graphics Shader Profiler and get back to you.