ggml-org/llama.cpp b11752

on GitHub

tests : make MoE router selection independent of the backend noise (#30818)

• tests : make MoE router selection independent of the backend noise

The router scores are in the range [0, 1), so a random draw can leave the
last expert (or expert group) still selected and the first one dropped tied
within the noise between the backends. They then route a token to different
experts and the logits differ by 4e-3 instead of the usual 5e-7.

Beam is the only arch here with a real top-k (8 experts, 2 used) and a group
top-k (4 groups, 2 used), so it is the only one that hits this: 2 of 20 seeds
failed on an M2 Ultra, the other MoE archs select 2 of 2 and cannot tie.

Fill the selection bias with a ramp of step 2 to give every expert a score
range of its own, which turns the top-k into a function of the expert index
alone. The bias affects only the selection, the weights still come from the
unbiased probs, so the MoE output keeps its magnitude. Beam now matches the
CPU reference within 4e-7 for all of 160 seeds.

Assisted-by: pi:llama.cpp/ggml-org/Qwen3.8-Flash-Next-GGUF (MacBook, M5 Max, 128GB)

• tests : tell the CPU and the GPU of an Apple SoC apart in the device table

Both devices report the same description ("Apple M2 Ultra" here), so the
device column of the test table had two indistinguishable rows and a failing
row did not say whether the Metal device or the host CPU produced it.

Add the device name, which is also what -b takes, unless the description
already is the name.

Assisted-by: pi:llama.cpp/ggml-org/Qwen3.8-Flash-Next-GGUF (MacBook, M5 Max, 128GB)