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esh-pfi-infrastructure/services/meromero-quant/cpu_smoke.py
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vh 1a5bc2ddf1 Land the MeroMero v2-31B NVFP4A16 quant and record the pinned-transformers trap
The v2 dense quant had failed four times. Attempt 5 lands it at 19 G.

The blocker was not what it looked like. `AmbiguousGlobalPerLayerAttributeError`
on `head_dim` read as a malformed upload -- DogOnKeyboard's config carries a
`per_layer_config` key zerofata's canonical one lacks -- and the standing fix was
to force `allow_global_per_layer_attribute_access=True`. Both halves were wrong.

`pip install llmcompressor==0.13.0` downgrades transformers 5.16.1 -> 5.14.1. The
config was serialized by 5.16.1, which materializes `per_layer_config` from
`global_head_dim` + `layer_types`; 5.14.1 carries the heterogeneity guard but not
the gemma4 resolver. Under the image's own transformers the same config loads
fine. `:latest` was also re-pulled during attempt 4 and no earlier run, so the
toolchain moved mid-diagnosis. Two things separated "malformed upload" from
"moved toolchain": reproducing the real failing call (a bare AutoConfig load does
not reproduce it; the trigger is reached through AutoTokenizer) and keeping
zerofata's canonical tree, quantized cleanly on 2026-08-21, as a positive control.

The fix drops `per_layer_config` rather than forcing global access. It is exactly
redundant -- keys are precisely the ten full_attention layer indices, sole value
(512, 4), verbatim the global fields -- and forcing instead would make
`config.head_dim` answer 256 to the callers building the 512-wide layers.
patch_perlayer.py re-proves that redundancy at apply time and refuses if it ever
stops holding.

Verified on the tensor table rather than the exit code: the output is identical
family-for-family and count-for-count to the August canonical quant, with 356
BF16 vision-tower tensors preserved and input_activations=None. A GPU-free load
leaves 0 tensors on meta and generates coherent prose. The section 4.4 serve test
has NOT run -- GPU1 has 19.9 GB free against 19.5 GB of weights, so it needs a
live seat displaced.

Also fixes the A4B output, which had a truncation cap baked into its tokenizer
(max_length 8192) from being quantized with the calibration corpus.

Playbook gains section 3.17 for the pinned-transformers class and sharpens 3.16
to say drop the dataset outright for any A16 scheme.
2026-09-10 10:56:16 -07:00

58 lines
2.6 KiB
Python

"""GPU-free load-and-generate smoke test for the quantized tree.
§4.4 says test on a temp port, never on the live seat -- but GPU1 has 19.9 GB free
against 19.5 GB of weights, so a vLLM serve test cannot happen without displacing a
live seat, and that is not my call. This is what CAN be established without one:
that the checkpoint's tensor names map cleanly onto the architecture (no missing or
unexpected keys), that compressed-tensors can decompress it, and that it emits
plausible tokens rather than garbage.
What it does NOT establish: that vLLM's sm_120 NVFP4 kernels serve it, or anything
about long-context quality. Those still need the GPU. Saying so is part of the
result -- a smoke test whose limits go unstated gets read as more than it is.
Deliberately greedy and short. This is an "is it wired up" check, not an eval; n=1
proves nothing about quality and is not offered as if it did.
"""
import sys
import time
import torch
from transformers import AutoTokenizer
path = sys.argv[1]
print(f"tree: {path}", flush=True)
t0 = time.time()
tok = AutoTokenizer.from_pretrained(path)
print(f"tokenizer OK ({time.time()-t0:.1f}s) truncation_side={tok.truncation_side}", flush=True)
t0 = time.time()
from transformers import AutoModelForImageTextToText as M
model = M.from_pretrained(path, dtype=torch.bfloat16, device_map=None)
print(f"model loaded on CPU ({time.time()-t0:.1f}s) {type(model).__name__}", flush=True)
n = sum(p.numel() for p in model.parameters())
print(f"parameters: {n/1e9:.2f} B", flush=True)
# Any tensor still sitting on meta means a weight the checkpoint never supplied --
# from_pretrained does not always raise on that, it just leaves the hole.
meta = [k for k, v in model.state_dict().items() if v.is_meta]
print(f"tensors still on meta device: {len(meta)}"
+ (f" *** {meta[:5]}" if meta else " (none -- every weight was materialised)"), flush=True)
msgs = [{"role": "user", "content": "In one sentence, what is a lighthouse for?"}]
enc = tok.apply_chat_template(msgs, add_generation_prompt=True, return_tensors="pt")
# transformers 5.x hands back a BatchEncoding here, not a bare tensor.
ids = enc["input_ids"] if hasattr(enc, "keys") else enc
print(f"prompt tokens: {ids.shape[-1]}", flush=True)
t0 = time.time()
with torch.inference_mode():
out = model.generate(ids, max_new_tokens=24, do_sample=False)
dt = time.time() - t0
text = tok.decode(out[0][ids.shape[-1]:], skip_special_tokens=True)
print(f"generated {out.shape[-1]-ids.shape[-1]} tokens in {dt:.1f}s "
f"({dt/max(1,out.shape[-1]-ids.shape[-1]):.1f}s/tok, CPU)", flush=True)
print(f"OUTPUT: {text!r}", flush=True)