Comment-only pass over the Python this PR touches: drop what the code already says, collapse multi-line explanations that still read on one line, and keep the reasoning that is not recoverable from the code. No code, docstring semantics or behaviour changes; verified with an AST comparison against the previous revision, and the backend suite is unchanged (same 37 environment failures as before: the API integration tests that need a live keyed server, the flash-attn install hooks, and the GPU memory fields).
301 lines
11 KiB
Python
301 lines
11 KiB
Python
# SPDX-License-Identifier: AGPL-3.0-only
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# Copyright 2026-present the Unsloth AI Inc. team. All rights reserved. See /studio/LICENSE.AGPL-3.0
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"""torch>=2.11 NVFP4 probe. Three parts:
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A. diagnostics -- torch/torchao versions, cpp-extension load state, device.
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B. GEMM micro -- isolated per-linear forward latency (bf16 / fp8 / nvfp4-cutlass /
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nvfp4-triton) at Z-Image-like shapes, to measure raw FP4
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tensor-core throughput free of pipeline overhead.
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C. end-to-end -- real dense Z-Image transformer, latency + LPIPS + PSNR + VRAM,
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reference = dense bf16 eager.
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Run on one CUDA (Blackwell) GPU. This is the experiment that decides whether NVFP4
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becomes a genuine speedup once torch>=2.11 + torchao's CUTLASS FP4 GEMM is present."""
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from __future__ import annotations
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import argparse
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import sys
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import time
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from pathlib import Path
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import numpy as np
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BASE = "Tongyi-MAI/Z-Image-Turbo"
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PROMPT = "A cinematic photograph of a red fox in a snowy forest at dawn, highly detailed"
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OUT = Path(__file__).resolve().parent.parent / "outputs" / "quant_research" / "nvfp4_t211_images"
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# ----------------------------------------------------------------------------- diag
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def diagnostics() -> None:
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import torch
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import torchao
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print("== A. diagnostics ==", flush = True)
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print(f" torch {torch.__version__}", flush = True)
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print(f" torchao {torchao.__version__}", flush = True)
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print(f" cuda {torch.version.cuda}", flush = True)
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if torch.cuda.is_available():
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print(
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f" device {torch.cuda.get_device_name(0)} sm{torch.cuda.get_device_capability(0)}",
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flush = True,
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)
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print(f" torch.ops.torchao present: {hasattr(torch.ops, 'torchao')}", flush = True)
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print(
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f" fp4 primitives: e2m1={hasattr(torch, 'float4_e2m1fn_x2')} "
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f"e8m0={hasattr(torch, 'float8_e8m0fnu')} _scaled_mm={hasattr(torch, '_scaled_mm')}",
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flush = True,
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)
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# torchao prints "Skipping import of cpp extensions ..." on torch<2.11; absence of that line
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# on 2.11 means the CUTLASS FP4 GEMM extension is live.
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print(
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" (no 'Skipping import of cpp extensions' line above => cpp/CUTLASS ext loaded)",
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flush = True,
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)
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# ----------------------------------------------------------------------------- micro
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def _configs():
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from torchao.quantization import Float8DynamicActivationFloat8WeightConfig as FP8
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from torchao.prototype.mx_formats import NVFP4DynamicActivationNVFP4WeightConfig as NV
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return {
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"bf16": None,
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"fp8": FP8(),
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"nvfp4_cutlass": NV(use_triton_kernel = False),
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"nvfp4_triton": NV(use_triton_kernel = True),
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}
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def _bench_linear(K, N, M, cfg, iters, compile_):
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import torch
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import torch.nn as nn
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from torchao.quantization import quantize_
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torch.compiler.reset()
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torch.cuda.empty_cache()
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m = nn.Sequential(nn.Linear(K, N, bias = False)).cuda().to(torch.bfloat16)
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if cfg is not None:
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quantize_(m, cfg)
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fn = torch.compile(m, fullgraph = True, dynamic = False) if compile_ else m
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x = torch.randn(M, K, device = "cuda", dtype = torch.bfloat16)
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with torch.no_grad():
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for _ in range(3): # warmup / compile
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fn(x)
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torch.cuda.synchronize()
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dts = []
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for _ in range(iters):
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t0 = time.perf_counter()
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fn(x)
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torch.cuda.synchronize()
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dts.append(time.perf_counter() - t0)
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del m, fn, x
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torch.cuda.empty_cache()
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med = sorted(dts)[len(dts) // 2]
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tflops = 2.0 * M * K * N / med / 1e12
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return med, tflops
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def micro(M, iters, compile_):
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print(f"\n== B. GEMM micro (M={M}, compile={compile_}, iters={iters}) ==", flush = True)
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# (K, N): qkv-ish, mlp-up, mlp-down for a ~3072-dim DiT
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shapes = [(3072, 3072), (3072, 12288), (12288, 3072)]
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cfgs = _configs()
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for K, N in shapes:
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print(f" shape K={K} N={N}:", flush = True)
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base_ms = None
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fp8_ms = None
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for name, cfg in cfgs.items():
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try:
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med, tfl = _bench_linear(K, N, M, cfg, iters, compile_)
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ms = med * 1e3
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if name == "bf16":
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base_ms = ms
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if name == "fp8":
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fp8_ms = ms
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vs_bf16 = f"{base_ms/ms:.2f}x" if base_ms else "-"
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vs_fp8 = f"{fp8_ms/ms:.2f}x" if fp8_ms else "-"
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print(
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f" {name:16s} {ms:7.3f} ms {tfl:7.1f} TFLOPS vs_bf16={vs_bf16:>6s} vs_fp8={vs_fp8:>6s}",
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flush = True,
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)
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except Exception as exc: # noqa: BLE001
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print(f" {name:16s} FAILED: {type(exc).__name__}: {str(exc)[:120]}", flush = True)
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# ----------------------------------------------------------------------------- e2e
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def _psnr(a, b):
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mse = float(np.mean((a.astype(np.float64) - b.astype(np.float64)) ** 2))
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return float("inf") if mse == 0 else float(10 * np.log10(255.0**2 / mse))
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_LP = {"fn": None}
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def _lpips(ref, arr):
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try:
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import lpips
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import torch
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if _LP["fn"] is None:
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_LP["fn"] = lpips.LPIPS(net = "alex", verbose = False).cuda().eval()
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def t(x):
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return (torch.from_numpy(x).float().permute(2, 0, 1).unsqueeze(0) / 127.5 - 1.0).cuda()
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with torch.no_grad():
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return float(_LP["fn"](t(ref), t(arr)).item())
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except Exception as exc: # noqa: BLE001
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print(f" (lpips: {type(exc).__name__})", flush = True)
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return None
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def _load_dense():
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import diffusers
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import torch
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t = diffusers.ZImageTransformer2DModel.from_pretrained(
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BASE, subfolder = "transformer", torch_dtype = torch.bfloat16
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)
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pipe = diffusers.ZImagePipeline.from_pretrained(BASE, torch_dtype = torch.bfloat16, transformer = t)
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pipe.to("cuda")
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return pipe
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def _gen(pipe, steps, seed, res):
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import torch
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g = torch.Generator(device = "cuda").manual_seed(seed)
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torch.cuda.synchronize()
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t0 = time.time()
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img = pipe(
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prompt = PROMPT,
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width = res,
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height = res,
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num_inference_steps = steps,
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guidance_scale = 0.0,
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generator = g,
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).images[0]
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torch.cuda.synchronize()
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return img, time.time() - t0
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def _median(xs):
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return sorted(xs)[len(xs) // 2]
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def e2e(steps, res, seed, iters, mf):
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import torch
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import torch.nn as nn
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OUT.mkdir(parents = True, exist_ok = True)
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def filt(mod, fqn = ""):
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return isinstance(mod, nn.Linear) and mod.in_features >= mf and mod.out_features >= mf
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def run(
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tag,
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*,
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cfg = None,
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compile = True,
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):
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torch.compiler.reset()
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torch.cuda.empty_cache()
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torch.cuda.reset_peak_memory_stats()
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pipe = _load_dense()
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if cfg is not None:
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from torchao.quantization import quantize_
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quantize_(pipe.transformer, cfg, filter_fn = filt)
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if compile:
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try:
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pipe.transformer.compile_repeated_blocks(fullgraph = True, dynamic = True)
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except Exception as exc: # noqa: BLE001
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print(
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f" [{tag}] compile failed: {type(exc).__name__}: {str(exc)[:90]}", flush = True
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)
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_gen(pipe, steps, seed, res) # warmup / compile
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dts, img = [], None
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for _ in range(iters):
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img, dt = _gen(pipe, steps, seed, res)
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dts.append(dt)
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gp = torch.cuda.max_memory_allocated() / 1e9
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arr = np.array(img)
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img.save(OUT / f"{tag}.png")
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del pipe
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torch.cuda.empty_cache()
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return _median(dts), arr, gp
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from torchao.prototype.mx_formats import NVFP4DynamicActivationNVFP4WeightConfig as NV
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from torchao.quantization import Float8DynamicActivationFloat8WeightConfig as FP8
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print(
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f"\n== C. end-to-end (Z-Image dense, {res}px, {steps} steps, min_feat={mf}) ==", flush = True
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)
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bref, ref, _ = run("bf16_eager", cfg = None, compile = False)
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print(f" bf16 eager ref: {bref:.3f}s", flush = True)
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rows = [("bf16_eager", bref, float("inf"), 0.0, None)]
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specs = [
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("bf16_compile", None, True),
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("fp8_compile", FP8(), True),
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("nvfp4_cutlass_compile", NV(use_triton_kernel = False), True),
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("nvfp4_triton_compile", NV(use_triton_kernel = True), True),
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]
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for tag, cfg, comp in specs:
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try:
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med, arr, gp = run(tag, cfg = cfg, compile = comp)
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ps, lp = _psnr(ref, arr), _lpips(ref, arr)
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rows.append((tag, med, ps, lp, gp))
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print(
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f" {tag:24s} {med:.3f}s ({bref/med:.2f}x vs eager) PSNR={ps:.1f} LPIPS={lp} VRAM={gp:.1f}G",
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flush = True,
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)
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except Exception as exc: # noqa: BLE001
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import traceback
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traceback.print_exc()
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print(f" {tag:24s} FAILED: {type(exc).__name__}: {str(exc)[:160]}", flush = True)
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rows.append((tag, None, None, None, None))
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fp8 = next((r[1] for r in rows if r[0] == "fp8_compile" and r[1]), None)
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print("\n==== SUMMARY (ref = bf16 dense eager) ====", flush = True)
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for tag, med, ps, lp, gp in rows:
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if med is None:
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print(f" {tag:24s} FAILED")
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continue
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vs_fp8 = f"{fp8/med:.2f}x" if fp8 else "-"
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psv = "inf" if ps == float("inf") else f"{ps:.1f}"
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lpv = (
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"ref"
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if (lp == 0.0 and tag == "bf16_eager")
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else (f"{lp:.3f}" if lp is not None else "n/a")
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)
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print(
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f" {tag:24s} {med:.3f}s vs_fp8:{vs_fp8:>6s} PSNR={psv:>5s} LPIPS={lpv:>6s}",
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flush = True,
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)
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def main(argv = None) -> int:
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p = argparse.ArgumentParser()
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p.add_argument("--steps", type = int, default = 8)
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p.add_argument("--res", type = int, default = 1024)
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p.add_argument("--seed", type = int, default = 42)
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p.add_argument("--iters", type = int, default = 3)
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p.add_argument("--micro-M", type = int, default = 4096)
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p.add_argument("--min-feat", type = int, default = 512)
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p.add_argument("--only", choices = ["diag", "micro", "e2e", "all"], default = "all")
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args = p.parse_args(argv)
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diagnostics()
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if args.only in ("micro", "all"):
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micro(args.micro_M, args.iters, compile_ = True)
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if args.only in ("e2e", "all"):
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e2e(args.steps, args.res, args.seed, args.iters, args.min_feat)
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print("NVFP4-T211-PROBE-DONE", flush = True)
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return 0
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if __name__ == "__main__":
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sys.path.insert(0, str(Path(__file__).resolve().parent.parent / "studio" / "backend"))
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sys.exit(main())
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