prefill bottlenecks on longer prompts

[byteyard]

Appreciate the detail. I don't think your conclusion is far off.

[quiettoken]

What exact setup are you running? Do you see the same thing with a smaller batch or shorter prompt?

[visionforge]

I'd approach it in a boring order. If you're on MLX, I'd confirm the version first and then reduce variables until the behavior is obvious. Once you know the plain path works, then add the faster path back in piece by piece.