Suya OCR API — vLLM-backed, OpenAI-compatible OCR service

FastAPI service wrapping the Surya-OCR-2 model (datalab-to) served through vLLM:
legacy /v1/api/ai/* endpoints, an OpenAI-compatible /v1/chat/completions endpoint,
a coalescing request batcher, a local OCR CLI, Docker packaging, multilingual
example outputs, and quantization/concurrency benchmarks.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

scripts/quant/__init__.py

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+"""Quantization benchmark harness for the Surya-OCR-2 recognition VLM."""

scripts/quant/aggregate.py

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+"""Summary-row contract and rendering to CSV + markdown."""
+from __future__ import annotations
+
+import csv
+import io
+from typing import Any, Dict, List
+
+SUMMARY_FIELDS = [
+    "method",
+    "status",
+    "t4_deployable",
+    "model_size_mb",
+    "mean_latency_s",
+    "p50_latency_s",
+    "p95_latency_s",
+    "throughput_rps",
+    "decode_tok_s",
+    "mean_cer",
+    "max_cer",
+    "mean_bbox_iou",
+    "mean_missed_lines",
+    "mean_extra_lines",
+    "error",
+]
+
+
+def build_row(**kwargs: Any) -> Dict[str, Any]:
+    unknown = set(kwargs) - set(SUMMARY_FIELDS)
+    if unknown:
+        raise KeyError(f"unknown summary field(s): {sorted(unknown)}")
+    row = {field: None for field in SUMMARY_FIELDS}
+    row.update(kwargs)
+    return row
+
+
+def rows_to_csv(rows: List[Dict[str, Any]]) -> str:
+    buf = io.StringIO()
+    writer = csv.DictWriter(buf, fieldnames=SUMMARY_FIELDS)
+    writer.writeheader()
+    for row in rows:
+        writer.writerow(row)
+    return buf.getvalue()
+
+
+def _fmt(value: Any) -> str:
+    if value is None:
+        return ""
+    if isinstance(value, float):
+        return f"{value:.4f}"
+    return str(value)
+
+
+def rows_to_markdown(rows: List[Dict[str, Any]]) -> str:
+    header = "| " + " | ".join(SUMMARY_FIELDS) + " |"
+    sep = "| " + " | ".join("---" for _ in SUMMARY_FIELDS) + " |"
+    lines = [header, sep]
+    for row in rows:
+        lines.append("| " + " | ".join(_fmt(row[f]) for f in SUMMARY_FIELDS) + " |")
+    return "\n".join(lines)

scripts/quant/bbox_iou.py

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+"""Greedy bbox IoU matching between reference and candidate page boxes."""
+from __future__ import annotations
+
+import json
+from pathlib import Path
+from typing import Dict, List, Sequence
+
+Box = Sequence[float]
+
+
+def iou(a: Box, b: Box) -> float:
+    ax0, ay0, ax1, ay1 = a
+    bx0, by0, bx1, by1 = b
+    ix0, iy0 = max(ax0, bx0), max(ay0, by0)
+    ix1, iy1 = min(ax1, bx1), min(ay1, by1)
+    iw, ih = max(0.0, ix1 - ix0), max(0.0, iy1 - iy0)
+    inter = iw * ih
+    if inter <= 0:
+        return 0.0
+    area_a = max(0.0, ax1 - ax0) * max(0.0, ay1 - ay0)
+    area_b = max(0.0, bx1 - bx0) * max(0.0, by1 - by0)
+    union = area_a + area_b - inter
+    return inter / union if union > 0 else 0.0
+
+
+def match_boxes(ref: List[Box], cand: List[Box], iou_threshold: float = 0.5) -> Dict[str, float]:
+    used = [False] * len(cand)
+    matched_ious: List[float] = []
+    for r in ref:
+        best_j, best_iou = -1, 0.0
+        for j, c in enumerate(cand):
+            if used[j]:
+                continue
+            cur = iou(r, c)
+            if cur > best_iou:
+                best_iou, best_j = cur, j
+        if best_j >= 0 and best_iou >= iou_threshold:
+            used[best_j] = True
+            matched_ious.append(best_iou)
+    matched = len(matched_ious)
+    return {
+        "matched": matched,
+        "missed": len(ref) - matched,
+        "extra": len(cand) - matched,
+        "mean_matched_iou": sum(matched_ious) / matched if matched else 0.0,
+    }
+
+
+def bbox_iou_over_dirs(ref_dir: Path, cand_dir: Path, iou_threshold: float = 0.5) -> Dict:
+    per_file: Dict[str, Dict[str, float]] = {}
+    for ref_path in sorted(ref_dir.glob("*.json")):
+        ref_boxes = json.loads(ref_path.read_text(encoding="utf-8")).get("boxes", [])
+        cand_path = cand_dir / ref_path.name
+        cand_boxes = (
+            json.loads(cand_path.read_text(encoding="utf-8")).get("boxes", [])
+            if cand_path.exists()
+            else []
+        )
+        per_file[ref_path.name] = match_boxes(ref_boxes, cand_boxes, iou_threshold)
+    n = len(per_file) or 1
+    return {
+        "mean_bbox_iou": sum(v["mean_matched_iou"] for v in per_file.values()) / n,
+        "mean_missed_lines": sum(v["missed"] for v in per_file.values()) / n,
+        "mean_extra_lines": sum(v["extra"] for v in per_file.values()) / n,
+        "per_file": per_file,
+    }

scripts/quant/build_model.py

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+"""Produce vLLM-loadable quantized checkpoints.
+
+compressor methods (int8/awq/gptq) use llm-compressor `oneshot`.
+bnb methods (bnb8/bnb4) use transformers + BitsAndBytesConfig + save_pretrained.
+baseline/online (bf16/fp8) need no build.
+"""
+from __future__ import annotations
+
+from pathlib import Path
+from typing import List
+
+from scripts.quant.recipes import METHOD_SPECS
+
+
+def needs_build(method: str) -> bool:
+    return METHOD_SPECS[method]["kind"] in ("compressor", "bnb")
+
+
+def _is_built(out_dir: Path) -> bool:
+    return (out_dir / "config.json").exists()
+
+
+CALIB_MAX_SEQ_LEN = 8192
+# Never quantize the LM head or the vision tower: vision modules are shape-fragile
+# (see the FP8 Marlin failure) and contribute little to decode cost.
+QUANT_IGNORE = ["re:.*lm_head", "re:.*visual.*", "re:.*vision.*"]
+
+
+def _calibration_dataset(calib_images: List[Path], processor):
+    """HF Dataset of pre-tokenized multimodal samples (batch dim kept), matching
+    llm-compressor's multimodal-vision examples; re-tensorized by _data_collator.
+    Activation calibration only needs representative forward passes, not the
+    exact training prompt."""
+    from datasets import Dataset
+    from PIL import Image
+
+    samples = []
+    for path in calib_images:
+        image = Image.open(path).convert("RGB")
+        messages = [{
+            "role": "user",
+            "content": [
+                {"type": "image"},
+                {"type": "text", "text": "OCR this document."},
+            ],
+        }]
+        prompt = processor.apply_chat_template(messages, add_generation_prompt=True, tokenize=False)
+        inputs = processor(
+            text=[prompt], images=[image],
+            padding=False, truncation=True, max_length=CALIB_MAX_SEQ_LEN,
+        )
+        samples.append({k: (v.tolist() if hasattr(v, "tolist") else v) for k, v in inputs.items()})
+    return Dataset.from_list(samples)
+
+
+def _data_collator(batch):
+    import torch
+
+    assert len(batch) == 1
+    return {key: torch.tensor(value) for key, value in batch[0].items()}
+
+
+def _build_compressor(method: str, base_model: str, out_dir: Path, calib_images: List[Path]) -> None:
+    from llmcompressor import oneshot
+    from llmcompressor.modifiers.quantization import GPTQModifier
+    from transformers import AutoProcessor
+
+    try:
+        from transformers import AutoModelForImageTextToText as _AutoModel
+    except ImportError:  # older transformers
+        from transformers import AutoModelForCausalLM as _AutoModel
+
+    spec = METHOD_SPECS[method]
+    model = _AutoModel.from_pretrained(base_model, dtype="auto", device_map="auto")
+    processor = AutoProcessor.from_pretrained(base_model)
+    dataset = _calibration_dataset(calib_images, processor)
+
+    if spec["modifier"] == "awq":
+        # llm-compressor main: AWQ is a transform paired with a QuantizationModifier.
+        from llmcompressor.modifiers.quantization import QuantizationModifier
+        try:
+            from llmcompressor.modifiers.transform.awq import AWQModifier
+        except ImportError:  # older layouts keep AWQModifier under modifiers.awq
+            from llmcompressor.modifiers.awq import AWQModifier
+        recipe = [
+            AWQModifier(duo_scaling=False),
+            QuantizationModifier(scheme=spec["scheme"], ignore=QUANT_IGNORE),
+        ]
+    else:
+        recipe = []
+        if spec.get("smoothquant"):
+            from llmcompressor.modifiers.smoothquant import SmoothQuantModifier
+            recipe.append(SmoothQuantModifier(smoothing_strength=0.8))
+        recipe.append(GPTQModifier(targets="Linear", scheme=spec["scheme"], ignore=QUANT_IGNORE))
+
+    oneshot(
+        model=model,
+        dataset=dataset,
+        recipe=recipe,
+        max_seq_length=CALIB_MAX_SEQ_LEN,
+        num_calibration_samples=len(dataset),
+        data_collator=_data_collator,
+    )
+    out_dir.mkdir(parents=True, exist_ok=True)
+    model.save_pretrained(out_dir, save_compressed=True)
+    processor.save_pretrained(out_dir)
+
+
+def _build_bnb(method: str, base_model: str, out_dir: Path) -> None:
+    import torch
+    from transformers import AutoProcessor, BitsAndBytesConfig
+
+    try:
+        from transformers import AutoModelForImageTextToText as _AutoModel
+    except ImportError:
+        from transformers import AutoModelForCausalLM as _AutoModel
+
+    bits = METHOD_SPECS[method]["bits"]
+    if bits == 8:
+        config = BitsAndBytesConfig(load_in_8bit=True)
+    else:
+        config = BitsAndBytesConfig(
+            load_in_4bit=True,
+            bnb_4bit_quant_type="nf4",
+            bnb_4bit_compute_dtype=torch.float16,
+            bnb_4bit_use_double_quant=True,
+        )
+    model = _AutoModel.from_pretrained(base_model, quantization_config=config, device_map="auto")
+    model.save_pretrained(out_dir)
+    AutoProcessor.from_pretrained(base_model).save_pretrained(out_dir)
+
+
+def build_model(method: str, base_model: str, out_dir: Path, calib_images: List[Path]) -> Path:
+    if not needs_build(method):
+        return Path(base_model)
+    out_dir = Path(out_dir)
+    if _is_built(out_dir):
+        return out_dir
+    kind = METHOD_SPECS[method]["kind"]
+    if kind == "compressor":
+        _build_compressor(method, base_model, out_dir, calib_images)
+    else:
+        _build_bnb(method, base_model, out_dir)
+    return out_dir

scripts/quant/capture.py

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+"""Capture per-page OCR text, bboxes, and latency from the vLLM OCR endpoint."""
+from __future__ import annotations
+
+import argparse
+import base64
+import json
+import sys
+from pathlib import Path
+from typing import Any, Dict
+
+import requests
+
+
+def extract_capture(body: Dict[str, Any]) -> Dict[str, Any]:
+    data = body.get("data") or {}
+    if not isinstance(data, dict):
+        data = {}
+    blocks = ((data.get("ocr_text_json") or {}).get("blocks")) or []
+    boxes = [list(b["bbox"]) for b in blocks if isinstance(b, dict) and b.get("bbox")]
+    return {
+        "text": data.get("text_lines", "") or "",
+        "boxes": boxes,
+        "elapsed_seconds": data.get("elapsed_seconds"),
+    }
+
+
+def write_capture(cap: Dict[str, Any], out_dir: Path, stem: str) -> None:
+    out_dir.mkdir(parents=True, exist_ok=True)
+    (out_dir / f"{stem}.txt").write_text(cap["text"], encoding="utf-8")
+    (out_dir / f"{stem}.json").write_text(
+        json.dumps({"boxes": cap["boxes"], "elapsed_seconds": cap["elapsed_seconds"]}),
+        encoding="utf-8",
+    )
+
+
+def _payload(image_path: Path) -> Dict[str, Any]:
+    suffix = image_path.suffix.lstrip(".").lower() or "png"
+    return {
+        "file": base64.b64encode(image_path.read_bytes()).decode("utf-8"),
+        "type": "jpg" if suffix == "jpeg" else suffix,
+        "skip_text_detection": False,
+        "skip_table_detection": False,
+        "recognize_math": False,
+        "ocr_with_boxes": True,
+    }
+
+
+def capture_page(url: str, image_path: Path, out_dir: Path, timeout: float) -> Dict[str, Any]:
+    resp = requests.post(url, json=_payload(image_path), timeout=timeout)
+    cap = extract_capture(resp.json())
+    if cap["elapsed_seconds"] is None:
+        # Latency is a headline metric; a successful response with no timing means
+        # the response contract changed. Surface it loudly instead of silently
+        # dropping the page from the latency stats.
+        print(
+            f"WARNING: no elapsed_seconds in OCR response for {image_path.name}; "
+            "latency for this page will be missing",
+            file=sys.stderr,
+        )
+    write_capture(cap, out_dir, image_path.stem)
+    return cap
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(description="Capture OCR text+boxes+latency per image.")
+    parser.add_argument("images", nargs="+", type=Path)
+    parser.add_argument("--url", required=True)
+    parser.add_argument("--out-dir", type=Path, required=True)
+    parser.add_argument("--timeout", type=float, default=900)
+    args = parser.parse_args()
+    for image in args.images:
+        cap = capture_page(args.url, image, args.out_dir, args.timeout)
+        print(f"captured {image.name}: {len(cap['boxes'])} boxes, {cap['elapsed_seconds']}s")
+
+
+if __name__ == "__main__":
+    main()

scripts/quant/finalize.py

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+"""Assemble the quantization benchmark summary from captured per-page outputs.
+
+Unlike run_all's inline scoring (which globs the reference and penalizes any page
+a method did not capture), this scores **candidate-driven**: for each method it
+scores only the pages that method actually produced, against the matching
+reference page. That lets fast methods run the full eval set while slow/eager
+methods (e.g. bitsandbytes) run a representative subset, without the subset being
+unfairly penalized for missing pages.
+
+Per-method status/reason and t4-deployability are passed in via a small spec so
+methods that could not be built or served are recorded as explicit failed rows.
+
+Run inside the bench container:  python3 -m scripts.quant.finalize
+"""
+from __future__ import annotations
+
+import json
+from pathlib import Path
+from typing import Any, Dict, List
+
+from scripts.cer_divergence import cer
+from scripts.quant.aggregate import build_row, rows_to_csv, rows_to_markdown
+from scripts.quant.bbox_iou import match_boxes
+
+WORK = Path("results/quant")
+REF = WORK / "reference"
+RESULTS = WORK / "results"
+
+# Per-method outcome metadata for this run (A100, vLLM v0.22.1 container).
+# status "ok" methods are scored from their captured pages — if a method has no
+# captures on disk it falls back to a failed row with `fallback_error`. "failed"
+# methods record why outright. bf16 is the reference (CER 0 / IoU 1 by construction).
+#
+# int8/awq/gptq were built with llm-compressor main (0.12.x): the PyPI 0.11 line
+# pins transformers<5 and cannot load qwen3_5, but main supports transformers 5.x.
+# int8 is plain GPTQ W8A8 (SmoothQuant default mappings unresolvable for qwen3_5).
+SPECS: List[Dict[str, Any]] = [
+    {"method": "bf16", "status": "ok", "t4_deployable": True, "is_reference": True},
+    {"method": "fp8", "status": "failed", "t4_deployable": False,
+     "error": "vLLM FP8 Marlin kernel: size_n=32 not divisible by tile_n_size=64 "
+              "(model layer shape incompatible with fp8 dynamic)"},
+    {"method": "int8", "status": "ok", "t4_deployable": True, "is_reference": False,
+     "fallback_error": "checkpoint built (llm-compressor main, GPTQ W8A8) but vLLM "
+                       "failed to serve it — see /tmp/serve_int8.log"},
+    {"method": "awq", "status": "ok", "t4_deployable": True, "is_reference": False,
+     "fallback_error": "checkpoint built (llm-compressor main, AWQ W4A16) but vLLM "
+                       "failed to serve it — see /tmp/serve_awq.log"},
+    {"method": "gptq", "status": "ok", "t4_deployable": True, "is_reference": False,
+     "fallback_error": "checkpoint built (llm-compressor main, GPTQ W4A16) but vLLM "
+                       "failed to serve it — see /tmp/serve_gptq.log"},
+    {"method": "bnb8", "status": "ok", "t4_deployable": True, "is_reference": False},
+    {"method": "bnb4", "status": "ok", "t4_deployable": True, "is_reference": False},
+]
+
+
+def _load_page(d: Path, stem: str):
+    j = json.loads((d / f"{stem}.json").read_text(encoding="utf-8"))
+    txt = (d / f"{stem}.txt").read_text(encoding="utf-8") if (d / f"{stem}.txt").exists() else ""
+    return j, txt
+
+
+def _score(method: str, is_reference: bool) -> Dict[str, Any]:
+    cand_dir = REF if is_reference else RESULTS / method
+    stems = sorted(p.stem for p in cand_dir.glob("*.json"))
+    latencies, cers, ious, missed, extra = [], [], [], [], []
+    for stem in stems:
+        cj, ctxt = _load_page(cand_dir, stem)
+        if cj.get("elapsed_seconds") is not None:
+            latencies.append(cj["elapsed_seconds"])
+        rj, rtxt = _load_page(REF, stem)
+        cers.append(cer(rtxt, ctxt))
+        m = match_boxes(rj.get("boxes", []), cj.get("boxes", []), iou_threshold=0.5)
+        ious.append(m["mean_matched_iou"])
+        missed.append(m["missed"])
+        extra.append(m["extra"])
+    latencies.sort()
+    n = len(latencies)
+    model_dir = WORK / "models" / method
+    size = None
+    if model_dir.exists():
+        size = round(sum(f.stat().st_size for f in model_dir.rglob("*") if f.is_file()) / (1024 * 1024), 1)
+    avg = lambda xs: round(sum(xs) / len(xs), 4) if xs else None
+    return {
+        "n_pages": len(stems),
+        "mean_latency_s": round(sum(latencies) / n, 2) if n else None,
+        "p50_latency_s": round(latencies[n // 2], 2) if n else None,
+        "p95_latency_s": round(latencies[min(n - 1, int(n * 0.95))], 2) if n else None,
+        "mean_cer": avg(cers),
+        "max_cer": round(max(cers), 4) if cers else None,
+        "mean_bbox_iou": avg(ious),
+        "mean_missed_lines": avg(missed),
+        "mean_extra_lines": avg(extra),
+        "model_size_mb": size,
+    }
+
+
+def main() -> None:
+    rows = []
+    for spec in SPECS:
+        if spec["status"] != "ok":
+            rows.append(build_row(method=spec["method"], status="failed",
+                                  t4_deployable=spec["t4_deployable"], error=spec["error"]))
+            continue
+        cand_dir = REF if spec.get("is_reference") else RESULTS / spec["method"]
+        if not any(cand_dir.glob("*.json")):
+            rows.append(build_row(method=spec["method"], status="failed",
+                                  t4_deployable=spec["t4_deployable"],
+                                  error=spec.get("fallback_error", "no captures on disk")))
+            continue
+        s = _score(spec["method"], spec.get("is_reference", False))
+        rows.append(build_row(
+            method=spec["method"], status="ok", t4_deployable=spec["t4_deployable"],
+            model_size_mb=s["model_size_mb"], mean_latency_s=s["mean_latency_s"],
+            p50_latency_s=s["p50_latency_s"], p95_latency_s=s["p95_latency_s"],
+            mean_cer=s["mean_cer"], max_cer=s["max_cer"], mean_bbox_iou=s["mean_bbox_iou"],
+            mean_missed_lines=s["mean_missed_lines"], mean_extra_lines=s["mean_extra_lines"],
+        ))
+        print(f"{spec['method']}: {s['n_pages']} pages, "
+              f"mean_latency={s['mean_latency_s']}s, mean_cer={s['mean_cer']}, iou={s['mean_bbox_iou']}")
+    (WORK / "summary.csv").write_text(rows_to_csv(rows), encoding="utf-8")
+    (WORK / "summary.json").write_text(json.dumps(rows, indent=2), encoding="utf-8")
+    (WORK / "summary.md").write_text(rows_to_markdown(rows), encoding="utf-8")
+    print(f"wrote summary for {len(rows)} methods to {WORK}")
+
+
+if __name__ == "__main__":
+    main()

scripts/quant/manifest.py

@@ -0,0 +1,18 @@
+"""Load the fixed eval-set manifest (one image filename per line)."""
+from __future__ import annotations
+
+from pathlib import Path
+from typing import List
+
+
+def load_manifest(manifest_path: Path, image_root: Path) -> List[Path]:
+    paths: List[Path] = []
+    for raw in manifest_path.read_text(encoding="utf-8").splitlines():
+        name = raw.strip()
+        if not name or name.startswith("#"):
+            continue
+        image = image_root / name
+        if not image.exists():
+            raise FileNotFoundError(f"manifest image not found: {name} (looked in {image_root})")
+        paths.append(image)
+    return paths

scripts/quant/plot.py

@@ -0,0 +1,78 @@
+"""Speed-vs-accuracy Pareto scatter and per-method bar charts."""
+from __future__ import annotations
+
+from pathlib import Path
+from typing import Any, Dict, List
+
+import matplotlib
+
+matplotlib.use("Agg")  # headless
+import matplotlib.pyplot as plt  # noqa: E402
+
+
+def pareto_points(rows: List[Dict[str, Any]], x_key: str, y_key: str) -> List[Dict[str, Any]]:
+    points = []
+    for row in rows:
+        if row.get("status") != "ok":
+            continue
+        if row.get(x_key) is None or row.get(y_key) is None:
+            continue
+        points.append({
+            "method": row["method"],
+            "x": row[x_key],
+            "y": row[y_key],
+            "t4_deployable": row.get("t4_deployable"),
+        })
+    return points
+
+
+def _scatter(points, x_label, y_label, title, out_path: Path) -> None:
+    fig, ax = plt.subplots(figsize=(7, 5))
+    for p in points:
+        marker = "o" if p["t4_deployable"] else "x"
+        ax.scatter(p["x"], p["y"], marker=marker, s=80)
+        ax.annotate(p["method"], (p["x"], p["y"]), textcoords="offset points", xytext=(5, 5))
+    ax.set_xlabel(x_label)
+    ax.set_ylabel(y_label)
+    ax.set_title(title + "  (o = T4-deployable, x = A100-only)")
+    fig.tight_layout()
+    fig.savefig(out_path, dpi=120)
+    plt.close(fig)
+
+
+def _bar(rows, metric_key, y_label, out_path: Path) -> None:
+    ok = [r for r in rows if r.get("status") == "ok" and r.get(metric_key) is not None]
+    fig, ax = plt.subplots(figsize=(7, 5))
+    ax.bar([r["method"] for r in ok], [r[metric_key] for r in ok])
+    ax.set_ylabel(y_label)
+    ax.set_title(metric_key)
+    fig.tight_layout()
+    fig.savefig(out_path, dpi=120)
+    plt.close(fig)
+
+
+def render_all(rows: List[Dict[str, Any]], out_dir: Path) -> List[Path]:
+    out_dir = Path(out_dir)
+    out_dir.mkdir(parents=True, exist_ok=True)
+    written: List[Path] = []
+
+    p1 = out_dir / "pareto_latency_cer.png"
+    _scatter(pareto_points(rows, "mean_latency_s", "mean_cer"),
+             "mean latency (s)  [lower=faster]", "CER vs BF16  [lower=better]",
+             "Speed vs recognition accuracy", p1)
+    written.append(p1)
+
+    p2 = out_dir / "pareto_latency_iou.png"
+    _scatter(pareto_points(rows, "mean_latency_s", "mean_bbox_iou"),
+             "mean latency (s)  [lower=faster]", "bbox IoU vs BF16  [higher=better]",
+             "Speed vs detection accuracy", p2)
+    written.append(p2)
+
+    for metric, label in [("mean_latency_s", "mean latency (s)"),
+                          ("mean_cer", "CER vs BF16"),
+                          ("mean_bbox_iou", "bbox IoU vs BF16")]:
+        bp = out_dir / f"bar_{metric}.png"
+        _bar(rows, metric, label, bp)
+        written.append(bp)
+
+    return written

scripts/quant/recipes.py

@@ -0,0 +1,50 @@
+"""Per-method quantization specs and vLLM serve-argument construction.
+
+kind:
+  baseline   - serve the unquantized model as-is (the accuracy reference)
+  online     - vLLM quantizes at load (fp8 dynamic); serve the base model
+  compressor - llm-compressor produced a checkpoint; quant config travels with it
+  bnb        - transformers+bitsandbytes produced a checkpoint; serve with bnb flags
+"""
+from __future__ import annotations
+
+from typing import Dict, List
+
+METHOD_SPECS: Dict[str, Dict] = {
+    "bf16": {"kind": "baseline", "t4_deployable": True},
+    "fp8": {"kind": "online", "vllm_quant": "fp8", "t4_deployable": False},
+    # smoothquant=False: SmoothQuant's default mappings fail to resolve for the
+    # qwen3_5 layer layout (each mapping matches all 24 input_layernorms), so
+    # int8 is plain GPTQ W8A8.
+    "int8": {"kind": "compressor", "modifier": "gptq", "scheme": "W8A8", "smoothquant": False, "t4_deployable": True},
+    "awq": {"kind": "compressor", "modifier": "awq", "scheme": "W4A16", "smoothquant": False, "t4_deployable": True},
+    "gptq": {"kind": "compressor", "modifier": "gptq", "scheme": "W4A16", "smoothquant": False, "t4_deployable": True},
+    "bnb8": {"kind": "bnb", "bits": 8, "t4_deployable": True},
+    "bnb4": {"kind": "bnb", "bits": 4, "t4_deployable": True},
+}
+
+
+def method_names() -> List[str]:
+    return list(METHOD_SPECS.keys())
+
+
+def vllm_serve_args(method: str, model_path: str, base_model: str, port: int) -> List[str]:
+    spec = METHOD_SPECS[method]
+    kind = spec["kind"]
+    serve_model = base_model if kind in ("baseline", "online") else model_path
+    args = [
+        "--host", "127.0.0.1",
+        "--port", str(port),
+        "--model", serve_model,
+        "--served-model-name", "datalab-to/surya-ocr-2",
+        "--max-model-len", "18000",
+        "--max-num-seqs", "16",
+        "--gpu-memory-utilization", "0.85",
+        "--enable-prefix-caching",
+        "--mm-processor-kwargs", '{"min_pixels":3136,"max_pixels":6291456}',
+    ]
+    if kind == "online":
+        args += ["--quantization", spec["vllm_quant"]]
+    elif kind == "bnb":
+        args += ["--quantization", "bitsandbytes", "--load-format", "bitsandbytes"]
+    return args

scripts/quant/run_all.py

@@ -0,0 +1,111 @@
+"""Orchestrate the quantization sweep: baseline -> each method -> aggregate -> plot.
+
+Each method is isolated: any exception becomes a status="failed" row so one bad
+method never aborts the sweep.
+"""
+from __future__ import annotations
+
+import argparse
+import json
+from pathlib import Path
+from typing import Any, Dict, List
+
+from scripts.quant.aggregate import build_row, rows_to_csv, rows_to_markdown
+from scripts.quant.bbox_iou import bbox_iou_over_dirs
+from scripts.quant.build_model import build_model
+from scripts.quant.capture import capture_page
+from scripts.quant.manifest import load_manifest
+from scripts.quant.recipes import METHOD_SPECS, method_names, vllm_serve_args
+from scripts.quant.serve import start_server, stop_server, wait_healthy
+
+# Reuse the existing CER metric.
+from scripts.cer_divergence import cer_over_dirs
+
+OCR_URL = "http://127.0.0.1:5002/v1/api/ai/suya_ocr_vllm/"
+
+
+def _dir_size_mb(path: Path) -> float:
+    total = sum(f.stat().st_size for f in path.rglob("*") if f.is_file())
+    return round(total / (1024 * 1024), 1)
+
+
+def _measure_method(method: str, base_model: str, work_dir: Path,
+                    eval_images: List[Path], reference_dir: Path) -> Dict[str, Any]:
+    """Build -> serve -> capture -> metrics for one method. Raises on any failure.
+
+    Assumes the API process (api.py) is already running and reads SURYA_INFERENCE_URL
+    from the env to point at the per-method vLLM server (port set by the runbook).
+    Returns a dict of measured summary fields (no method/status/t4 keys).
+    """
+    model_dir = work_dir / "models" / method
+    out_capture = work_dir / "results" / method
+    port = 8000
+
+    built = build_model(method, base_model, model_dir, eval_images[: min(8, len(eval_images))])
+    serve_args = vllm_serve_args(method, str(built), base_model, port)
+    proc = start_server(serve_args, str(work_dir / f"vllm_{method}.log"))
+    try:
+        if not wait_healthy(port):
+            raise RuntimeError(f"vLLM did not become healthy for {method}")
+        latencies = []
+        for image in eval_images:
+            cap = capture_page(OCR_URL, image, out_capture, timeout=900)
+            if cap["elapsed_seconds"] is not None:
+                latencies.append(cap["elapsed_seconds"])
+        cer = cer_over_dirs(reference_dir, out_capture)
+        iou = bbox_iou_over_dirs(reference_dir, out_capture)
+    finally:
+        stop_server(port, proc)
+
+    latencies.sort()
+    n = len(latencies)
+    size = _dir_size_mb(built) if METHOD_SPECS[method]["kind"] in ("compressor", "bnb") else None
+    return {
+        "mean_latency_s": round(sum(latencies) / n, 3) if n else None,
+        "p50_latency_s": latencies[n // 2] if n else None,
+        "p95_latency_s": latencies[min(n - 1, int(n * 0.95))] if n else None,
+        "mean_cer": cer["mean_cer"],
+        "max_cer": cer["max_cer"],
+        "mean_bbox_iou": iou["mean_bbox_iou"],
+        "mean_missed_lines": iou["mean_missed_lines"],
+        "mean_extra_lines": iou["mean_extra_lines"],
+        "model_size_mb": size,
+    }
+
+
+def run_method(method: str, base_model: str, work_dir: Path,
+              eval_images: List[Path], reference_dir: Path) -> Dict[str, Any]:
+    t4 = METHOD_SPECS[method]["t4_deployable"]
+    try:
+        metrics = _measure_method(method, base_model, work_dir, eval_images, reference_dir)
+        return build_row(method=method, status="ok", t4_deployable=t4, **metrics)
+    except Exception as exc:  # feasibility probe: record and continue
+        return build_row(method=method, status="failed", t4_deployable=t4, error=str(exc))
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(description="Run the quantization benchmark sweep.")
+    parser.add_argument("--base-model", default="datalab-to/surya-ocr-2")
+    parser.add_argument("--manifest", type=Path, default=Path("eval_set/manifest.txt"))
+    parser.add_argument("--image-root", type=Path, default=Path("."))
+    parser.add_argument("--work-dir", type=Path, default=Path("results/quant"))
+    parser.add_argument("--methods", nargs="*", default=method_names())
+    args = parser.parse_args()
+
+    eval_images = load_manifest(args.manifest, args.image_root)
+    reference_dir = args.work_dir / "reference"
+    args.work_dir.mkdir(parents=True, exist_ok=True)
+
+    rows = []
+    for method in args.methods:
+        print(f"=== {method} ===", flush=True)
+        rows.append(run_method(method, args.base_model, args.work_dir, eval_images, reference_dir))
+
+    (args.work_dir / "summary.csv").write_text(rows_to_csv(rows), encoding="utf-8")
+    (args.work_dir / "summary.json").write_text(json.dumps(rows, indent=2), encoding="utf-8")
+    (args.work_dir / "summary.md").write_text(rows_to_markdown(rows), encoding="utf-8")
+    print(f"wrote summary for {len(rows)} methods to {args.work_dir}")
+
+
+if __name__ == "__main__":
+    main()

scripts/quant/score_methods.sh

@@ -0,0 +1,60 @@
+#!/usr/bin/env bash
+# Serve and score compressor-built checkpoints (int8/gptq/awq) over a page subset.
+# Each method: hardened server teardown -> serve checkpoint -> health/fail watch ->
+# capture N_PAGES through the OCR API. Run INSIDE the bench container:
+#   bash scripts/quant/score_methods.sh int8 gptq awq
+# Requires api.py running on :5002 pointed at :8000.
+set -uo pipefail
+
+export LD_LIBRARY_PATH="/usr/local/cuda/compat:${LD_LIBRARY_PATH:-}"
+N_PAGES="${N_PAGES:-3}"
+OCR_URL="http://127.0.0.1:5002/v1/api/ai/suya_ocr_vllm/"
+LOG=/tmp/score_methods.log
+
+mapfile -t ALL < <(sed '/^#/d;/^$/d' eval_set/manifest.txt)
+IMAGES=("${ALL[@]:0:$N_PAGES}")
+
+stop_server() {
+  local pid
+  pid=$(ss -ltnp 2>/dev/null | grep ":8000 " | grep -oP 'pid=\K[0-9]+' | head -1)
+  [ -n "$pid" ] && kill -9 "$pid" 2>/dev/null
+  pkill -9 -f "vllm.entrypoints" 2>/dev/null
+  # EngineCore outlives the API server and holds the GPU; kill compute procs and
+  # poll until memory actually frees (kill returns before GPU release).
+  for p in $(nvidia-smi --query-compute-apps=pid --format=csv,noheader 2>/dev/null); do
+    kill -9 "$p" 2>/dev/null
+  done
+  for _ in $(seq 1 30); do
+    used=$(nvidia-smi --query-gpu=memory.used --format=csv,noheader,nounits | head -1)
+    [ "${used:-99999}" -lt 2000 ] && break
+    sleep 2
+  done
+}
+
+for m in "$@"; do
+  echo "=== scoring $m ===" | tee -a "$LOG"
+  stop_server
+  # VLLM_EXTRA_ARGS lets a caller add e.g. --dtype float16 (Exllama W4A16 kernel
+  # on Ampere only supports float16 activations).
+  nohup python3 -m vllm.entrypoints.openai.api_server --host 127.0.0.1 --port 8000 \
+    --model "results/quant/models/$m" --served-model-name datalab-to/surya-ocr-2 \
+    --max-model-len 18000 --max-num-seqs 16 --gpu-memory-utilization 0.85 \
+    --enable-prefix-caching --mm-processor-kwargs '{"min_pixels":3136,"max_pixels":6291456}' \
+    ${VLLM_EXTRA_ARGS:-} \
+    > "/tmp/serve_${m}.log" 2>&1 &
+  ok=0
+  for _ in $(seq 1 84); do
+    if curl -fs http://127.0.0.1:8000/health >/dev/null 2>&1; then ok=1; break; fi
+    if grep -qiE "Engine core initialization failed" "/tmp/serve_${m}.log" 2>/dev/null; then break; fi
+    sleep 5
+  done
+  if [ "$ok" -ne 1 ]; then
+    echo "$m: FAILED to start" | tee -a "$LOG"
+    continue
+  fi
+  python3 -m scripts.quant.capture --url "$OCR_URL" --out-dir "results/quant/results/$m" "${IMAGES[@]}" \
+    >> "$LOG" 2>&1
+  echo "$m: captured $(ls "results/quant/results/$m"/*.json 2>/dev/null | wc -l) pages" | tee -a "$LOG"
+done
+stop_server
+echo "SCORE_DONE" | tee -a "$LOG"

scripts/quant/serve.py

@@ -0,0 +1,59 @@
+"""Launch a vLLM OpenAI server for one quant variant, health-check it, and tear
+it down by port (never by command-line match — that bit us in Approach A)."""
+from __future__ import annotations
+
+import os
+import re
+import subprocess
+import time
+import urllib.request
+from typing import List, Optional
+
+# Default seconds to wait for a server to become healthy. Overridable via env so a
+# method that fails to boot is recorded quickly instead of blocking the sweep.
+DEFAULT_HEALTH_TIMEOUT = float(os.environ.get("SURYA_QUANT_HEALTH_TIMEOUT", "900"))
+
+
+def health_url(port: int) -> str:
+    return f"http://127.0.0.1:{port}/health"
+
+
+def parse_listening_pid(ss_output: str, port: int) -> Optional[int]:
+    for line in ss_output.splitlines():
+        if f":{port} " in line or line.rstrip().endswith(f":{port}"):
+            m = re.search(r"pid=(\d+)", line)
+            if m:
+                return int(m.group(1))
+    return None
+
+
+def wait_healthy(port: int, timeout: float = DEFAULT_HEALTH_TIMEOUT) -> bool:
+    deadline = time.time() + timeout
+    url = health_url(port)
+    while time.time() < deadline:
+        try:
+            with urllib.request.urlopen(url, timeout=2) as resp:
+                if resp.status == 200:
+                    return True
+        except Exception:
+            time.sleep(3)
+    return False
+
+
+def start_server(serve_args: List[str], log_path: str) -> subprocess.Popen:
+    cmd = ["python", "-m", "vllm.entrypoints.openai.api_server", *serve_args]
+    log = open(log_path, "w")
+    return subprocess.Popen(cmd, stdout=log, stderr=subprocess.STDOUT)
+
+
+def stop_server(port: int, proc: Optional[subprocess.Popen] = None) -> None:
+    if proc is not None:
+        proc.terminate()
+        try:
+            proc.wait(timeout=30)
+        except Exception:
+            proc.kill()
+    out = subprocess.run(["ss", "-ltnp"], capture_output=True, text=True).stdout
+    pid = parse_listening_pid(out, port)
+    if pid:
+        subprocess.run(["kill", str(pid)])

scripts/quant/tune_mtp.sh

@@ -0,0 +1,76 @@
+#!/usr/bin/env bash
+# MTP (multi-token-prediction) speculative-decode sweep for the latency report.
+# Serves the BF16 model three ways — no speculation (baseline), MTP with 1
+# speculative token, MTP with 2 — and captures the same page subset through the
+# OCR API for each. The model ships 1 nextn-predict layer, so MTP=1 is the
+# expected-valid setting and MTP=2 is exploratory.
+#
+# Run INSIDE the bench container:  bash scripts/quant/tune_mtp.sh
+# Requires: api.py running on :5002 pointed at :8000; compat libs on path.
+set -uo pipefail
+
+MODEL="${MODEL:-datalab-to/surya-ocr-2}"
+OCR_URL="http://127.0.0.1:5002/v1/api/ai/suya_ocr_vllm/"
+N_PAGES="${N_PAGES:-5}"
+OUT_ROOT="results/quant/mtp"
+LOG=/tmp/tune_mtp.log
+export LD_LIBRARY_PATH="/usr/local/cuda/compat:${LD_LIBRARY_PATH:-}"
+
+mapfile -t ALL < <(sed '/^#/d;/^$/d' eval_set/manifest.txt)
+IMAGES=("${ALL[@]:0:$N_PAGES}")
+
+# config_name | extra vLLM args. The speculative-config JSON is written compact
+# (no spaces) so it survives word-splitting as a single argv token.
+CONFIGS=(
+  "baseline|--enable-prefix-caching"
+  "mtp1|--enable-prefix-caching --speculative-config {\"method\":\"mtp\",\"num_speculative_tokens\":1}"
+  "mtp2|--enable-prefix-caching --speculative-config {\"method\":\"mtp\",\"num_speculative_tokens\":2}"
+)
+
+base_args() {
+  echo "--host 127.0.0.1 --port 8000 --model $MODEL --served-model-name $MODEL \
+--max-model-len 18000 --max-num-seqs 16 --gpu-memory-utilization 0.85 --no-enforce-eager \
+--mm-processor-kwargs {\"min_pixels\":3136,\"max_pixels\":6291456}"
+}
+
+stop_server() {
+  local pid
+  pid=$(ss -ltnp 2>/dev/null | grep ":8000 " | grep -oP 'pid=\K[0-9]+' | head -1)
+  [ -n "$pid" ] && kill -9 "$pid" 2>/dev/null
+  pkill -9 -f "vllm.entrypoints" 2>/dev/null
+  # EngineCore outlives the API server and holds the GPU; kill every remaining
+  # CUDA compute process, then poll until the memory is actually freed.
+  for p in $(nvidia-smi --query-compute-apps=pid --format=csv,noheader 2>/dev/null); do
+    kill -9 "$p" 2>/dev/null
+  done
+  for _ in $(seq 1 30); do
+    used=$(nvidia-smi --query-gpu=memory.used --format=csv,noheader,nounits | head -1)
+    [ "${used:-99999}" -lt 2000 ] && break
+    sleep 2
+  done
+}
+
+for entry in "${CONFIGS[@]}"; do
+  name="${entry%%|*}"
+  extra="${entry#*|}"
+  echo "=== mtp config: $name ($extra) ===" | tee -a "$LOG"
+  stop_server
+  # shellcheck disable=SC2046
+  nohup python3 -m vllm.entrypoints.openai.api_server $(base_args) $extra \
+    > "/tmp/mtp_${name}.log" 2>&1 &
+  ok=0
+  for _ in $(seq 1 96); do
+    if curl -fs http://127.0.0.1:8000/health >/dev/null 2>&1; then ok=1; break; fi
+    if grep -qiE "Engine core initialization failed|ValueError|RuntimeError|Traceback" "/tmp/mtp_${name}.log" 2>/dev/null; then break; fi
+    sleep 5
+  done
+  if [ "$ok" -ne 1 ]; then
+    echo "$name: FAILED to start (see /tmp/mtp_${name}.log)" | tee -a "$LOG"
+    continue
+  fi
+  python3 -m scripts.quant.capture --url "$OCR_URL" --out-dir "$OUT_ROOT/$name" "${IMAGES[@]}" \
+    >> "$LOG" 2>&1
+  echo "$name: captured $(ls "$OUT_ROOT/$name"/*.json 2>/dev/null | wc -l) pages" | tee -a "$LOG"
+done
+stop_server
+echo "MTP_DONE" | tee -a "$LOG"

scripts/quant/tune_vllm.sh

@@ -0,0 +1,77 @@
+#!/usr/bin/env bash
+# vLLM serving-parameter tuning sweep for the OCR latency report.
+# Serves the BF16 model under several vLLM flag combinations (CUDA graph vs eager,
+# prefix caching on/off, chunked prefill on/off), captures a fixed page subset
+# through the OCR API for each, and records per-config latency.
+#
+# Run INSIDE the bench container:  bash scripts/quant/tune_vllm.sh
+# Requires: api.py already running on :5002 pointed at :8000; compat libs on path.
+set -uo pipefail
+
+MODEL="${MODEL:-datalab-to/surya-ocr-2}"
+OCR_URL="http://127.0.0.1:5002/v1/api/ai/suya_ocr_vllm/"
+N_PAGES="${N_PAGES:-3}"
+OUT_ROOT="results/quant/tuning"
+LOG=/tmp/tune_vllm.log
+export LD_LIBRARY_PATH="/usr/local/cuda/compat:${LD_LIBRARY_PATH:-}"
+
+mapfile -t ALL < <(sed '/^#/d;/^$/d' eval_set/manifest.txt)
+IMAGES=("${ALL[@]:0:$N_PAGES}")
+
+# config_name | extra vLLM args
+CONFIGS=(
+  "default|--enable-prefix-caching"
+  "eager|--enable-prefix-caching --enforce-eager"
+  "no_prefix_cache|--no-enable-prefix-caching"
+  "no_chunked_prefill|--enable-prefix-caching --no-enable-chunked-prefill"
+)
+
+base_args() {
+  echo "--host 127.0.0.1 --port 8000 --model $MODEL --served-model-name $MODEL \
+--max-model-len 18000 --max-num-seqs 16 --gpu-memory-utilization 0.85 \
+--mm-processor-kwargs {\"min_pixels\":3136,\"max_pixels\":6291456}"
+}
+
+stop_server() {
+  local pid
+  pid=$(ss -ltnp 2>/dev/null | grep ":8000 " | grep -oP 'pid=\K[0-9]+' | head -1)
+  [ -n "$pid" ] && kill -9 "$pid" 2>/dev/null
+  pkill -9 -f "vllm.entrypoints" 2>/dev/null
+  # The EngineCore worker holds the GPU and outlives the API server; kill every
+  # remaining CUDA compute process, then poll until the memory is actually freed
+  # (kill returns immediately, GPU release lags).
+  for p in $(nvidia-smi --query-compute-apps=pid --format=csv,noheader 2>/dev/null); do
+    kill -9 "$p" 2>/dev/null
+  done
+  for _ in $(seq 1 30); do
+    used=$(nvidia-smi --query-gpu=memory.used --format=csv,noheader,nounits | head -1)
+    [ "${used:-99999}" -lt 2000 ] && break
+    sleep 2
+  done
+}
+
+for entry in "${CONFIGS[@]}"; do
+  name="${entry%%|*}"
+  extra="${entry#*|}"
+  echo "=== tuning config: $name ($extra) ===" | tee -a "$LOG"
+  stop_server
+  # shellcheck disable=SC2046
+  nohup python3 -m vllm.entrypoints.openai.api_server $(base_args) $extra \
+    > "/tmp/tune_${name}.log" 2>&1 &
+  # wait for health or crash (max 7 min)
+  ok=0
+  for _ in $(seq 1 84); do
+    if curl -fs http://127.0.0.1:8000/health >/dev/null 2>&1; then ok=1; break; fi
+    if grep -qiE "Engine core initialization failed|RuntimeError" "/tmp/tune_${name}.log" 2>/dev/null; then break; fi
+    sleep 5
+  done
+  if [ "$ok" -ne 1 ]; then
+    echo "$name: FAILED to start" | tee -a "$LOG"
+    continue
+  fi
+  python3 -m scripts.quant.capture --url "$OCR_URL" --out-dir "$OUT_ROOT/$name" "${IMAGES[@]}" \
+    >> "$LOG" 2>&1
+  echo "$name: captured $(ls "$OUT_ROOT/$name"/*.json 2>/dev/null | wc -l) pages" | tee -a "$LOG"
+done
+stop_server
+echo "TUNE_DONE" | tee -a "$LOG"