Qwen3.8 125B (6B active) Flash-Next

User reports a custom llama.cpp Vulkan backend patch for Qwen3.8-Flash-Next improves prompt processing from 346 to 448 t/s and generation from 13.3 to 14.4 t/s at 2.7k context. At 131k context, prompt processing improves from 195 to 263 t/s and generation from 9.1 to 10.4 t/s. The patch fixes a top-k fallback to CPU in sparse attention. Greedy outputs are identical, the needle is found at 131k, and images are read correctly.