The "llama.cpp install via unsloth_zoo.llama_cpp" step ran inside every
cell of the consolidated `Core` matrix (HF=4.57.6+TRL<1, HF=latest+
TRL=latest, HF=default+TRL=default) at ~275 s wallclock per cell. The
artefact it produces (a fresh ggml-org/llama.cpp build) has nothing to
do with the (transformers, TRL) combo, so 2/3 of those minutes were
duplicated work -- ~9 min of CPU per PR push, on every push.
Factor the step into a sibling job `llama-cpp-smoke` that runs once.
Each Core cell now ends after the matrix-relevant work (deps + Bucket-A
+ unsloth_zoo pytest + compile sweep + MoE patches). The new job pins
the same env contract (UNSLOTH_IS_PRESENT, UNSLOTH_COMPILE_DISABLE,
PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=python, PYTHONPATH=studio) and
mirrors the matrix install minus pieces unrelated to llama_cpp:
studio.txt's FastAPI stack, bitsandbytes, triton, mammoth/unpdf,
datasets, pytest, sqlalchemy/cryptography. Keeps torch from the same
CPU index, transformers/trl from pyproject defaults (so unsloth_zoo's
temporary_patches.* per-architecture submodules import cleanly), and
the requests / tqdm / psutil that llama_cpp.py reaches for at module
top.
Net per-PR effect:
Old: 3 x 12 min = 36 min CPU on llama.cpp build (one cmake per cell)
New: 3 x 7 min + 1 x 7 min = 28 min CPU
That's ~8 min of free CPU back per PR, and each Core cell finishes
~5 min sooner so downstream-gated checks unblock faster.
The actual smoke step body is unchanged -- same `_zoo_aggressive_cuda_
spoof.apply()` import-time harness, same `install_llama_cpp` round-
trip, same `llama-cli --help` and `llama-quantize --help` text checks.
Per-step `continue-on-error` is still absent; a real build failure
fails the PR.