> you could probably implement training and inference for a single model architecture, from scratch, on a single kind of GPU, with reasonable performance… with a year or so
A year might be required when the only input is the research articles. In practice, we also have reference Python implementations of these models. Possible to test different functions or compute shaders against the corresponding pieces from the reference implementations, by comparing saved output tensors between the reference and the newly built implementation. Due to that simple trick, I think I have spent less than 1 month part-time for each of these two projects.
I'd say a year for somebody who doesn't know what a linear layer is and couldn't explain why a GPU might be of any use if you're not playing games, but who knows what the derivative of 3x^2 is.
I have implemented inference of Whisper https://github.com/Const-me/Whisper and Mistral https://github.com/Const-me/Cgml/tree/master/Mistral/Mistral... models on all GPUs which support Direct3D 11.0 API. The performance is IMO very reasonable.
A year might be required when the only input is the research articles. In practice, we also have reference Python implementations of these models. Possible to test different functions or compute shaders against the corresponding pieces from the reference implementations, by comparing saved output tensors between the reference and the newly built implementation. Due to that simple trick, I think I have spent less than 1 month part-time for each of these two projects.