ggml-org/llama.cpp b12207

on GitHub

ggml-cuda : add d_state=64 fast path to SSM_SCAN kernel (#31818)

Zamba2 and similar architectures use a state size of 64 in their
recurrent-scan step, which fell outside the GPU kernel's existing
fast paths (96, 128, 256). Every scan step was falling back to CPU,
bottlenecking generation to 6-7 tok/s against the 50-70 tok/s band
other architectures achieve on the same hardware.

Add a 4th template instantiation for d_state=64, following the
existing pattern; no change to the underlying math. Verified against
the existing CPU-reference correctness harness with 3 new test cases
built from Zamba2's real hyperparameters (28/28 passing).

Measured ~35% throughput improvement (11 -> 15.1 tok/s) on Zamba2-7B-
Instruct. Full parity with other architectures not yet reached - a
separate, unrelated fraction of scan calls (~28%) still falls back to
CPU for a cause not yet diagnosed.

Assisted-by: Claude Sonnet 5

Co-authored-by: Sargentmajord 331229907+sargentmajord@users.noreply.github.com