Files
nvfp4-megamoe-kernel/tests/layertest.py
biondizzle 09ff5c5b98 feat: full NVFP4 MoE pipeline (L1→SiLU→L2→scatter)
cutedsl/moe_pipeline.py: complete pipeline
  - stage_activation: BF16 → NVFP4 (keeps data in FP4)
  - L1 GEMM: NVFP4 × NVFP4 → BF16 (gate+up)
  - SiLU(gate) * up: BF16 (only nonlinear, can't avoid)
  - Re-quantize: BF16 → NVFP4 (back to native)
  - L2 GEMM: NVFP4 × NVFP4 → BF16 (down_proj)
  - Scatter with routing weights → BF16 output

layertest.py: now tests the FULL MoE pipeline against BF16 reference.

NVFP4-native: both GEMMs use float4_e2m1fn_x2 for A and B,
float8_e4m3fn for block scales, float32 for global scales.
BF16 only for SiLU activation and final scatter.
2026-05-16 03:22:43 +00:00

302 lines
11 KiB
Python

#!/usr/bin/env python3
"""
Layer 0 kernel comparison test: CuTeDSL NVFP4 kernel vs BF16 reference.
No vLLM, no Docker, no tensor parallelism. Just raw weights + CuTeDSL kernel.
If cosine < 0.99, the test exits with error.
Uses the bridge layer in cutedsl/bridge.py for tensor layout conversion.
"""
import os
import sys
import json
import glob
import torch
from safetensors import safe_open
# Add repo root to path
REPO_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
sys.path.insert(0, REPO_ROOT)
from cutedsl.bridge import (
quantize_to_nvfp4,
quantize_weight_to_nvfp4,
assemble_scales_2d_side,
assemble_scales_3d_side,
make_b_k_major,
compute_expert_offsets,
run_nvfp4_grouped_gemm,
)
from cutedsl.moe_pipeline import (
stage_activation,
prepare_nvfp4_moe_weights,
run_nvfp4_moe,
)
# ── Constants ──────────────────────────────────────────────────────────
NVFP4_MODEL_DIR = "/root/nvidia-meeting/DeepSeek-V4-Pro-NVFP4"
LAYER_IDX = 0
DEVICE = "cuda"
COSINE_THRESHOLD = 0.99
# E2M1 FP4 lookup table (for BF16 dequant reference)
E2M1_LUT = torch.tensor([
0.0, 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 6.0,
-0.0, -0.5, -1.0, -1.5, -2.0, -3.0, -4.0, -6.0,
], dtype=torch.float32)
# ── Checkpoint loading ─────────────────────────────────────────────────
def find_shards(model_dir):
index_path = os.path.join(model_dir, "model.safetensors.index.json")
key_to_shard = {}
if os.path.exists(index_path):
with open(index_path) as f:
index = json.load(f)
for key, shard in index["weight_map"].items():
key_to_shard[key] = os.path.join(model_dir, shard)
else:
for sf in glob.glob(os.path.join(model_dir, "*.safetensors")):
with safe_open(sf, framework="pt") as f:
for key in f.keys():
key_to_shard[key] = sf
return key_to_shard
def load_layer_tensors(model_dir, layer_idx):
"""Load all tensors for a specific layer. Keys normalized (no 'model.' prefix)."""
key_to_shard = find_shards(model_dir)
layer_prefix = f"layers.{layer_idx}."
shard_to_keys = {}
for key, shard in key_to_shard.items():
norm_key = key.removeprefix("model.")
if not norm_key.startswith(layer_prefix):
continue
shard_to_keys.setdefault(shard, []).append((key, norm_key))
tensors = {}
for shard, keys in shard_to_keys.items():
with safe_open(shard, framework="pt") as f:
for orig_key, norm_key in keys:
tensors[norm_key] = f.get_tensor(orig_key)
return tensors
# ── NVFP4 Dequantization (BF16 reference) ─────────────────────────────
def dequantize_nvfp4_weight(packed_uint8, scale_e4m3, global_scale):
"""Dequantize NVFP4 (E2M1 + E4M3 + global) to BF16."""
device = packed_uint8.device
lut = E2M1_LUT.to(device)
lower = lut[(packed_uint8 & 0x0F).long()]
upper = lut[((packed_uint8 >> 4) & 0x0F).long()]
out_features = packed_uint8.shape[0]
in_features = packed_uint8.shape[1] * 2
unpacked = torch.empty(out_features, in_features, dtype=torch.float32, device=device)
unpacked[:, 0::2] = lower
unpacked[:, 1::2] = upper
block_scale = scale_e4m3.float()
block_expanded = block_scale.repeat_interleave(16, dim=1)[:, :in_features]
return (unpacked * block_expanded * global_scale).to(torch.bfloat16)
def dequantize_nvfp4_experts(nvfp4_tensors, layer_idx, expert_indices):
"""Dequantize expert weights from NVFP4 checkpoint → BF16."""
experts = {}
for e in expert_indices:
expert = {}
for proj in ["gate_proj", "up_proj", "down_proj"]:
weight_key = f"layers.{layer_idx}.mlp.experts.{e}.{proj}.weight"
scale_key = f"layers.{layer_idx}.mlp.experts.{e}.{proj}.weight_scale"
gs_key = f"layers.{layer_idx}.mlp.experts.{e}.{proj}.weight_scale_2"
if weight_key not in nvfp4_tensors:
if proj == "down_proj" and e == 211:
continue
raise KeyError(f"Missing {weight_key}")
weight = nvfp4_tensors[weight_key].to(DEVICE)
scale = nvfp4_tensors[scale_key].to(DEVICE)
global_scale = nvfp4_tensors[gs_key].item()
expert[proj] = dequantize_nvfp4_weight(weight, scale, global_scale)
experts[e] = expert
return experts
# ── BF16 MoE Forward ───────────────────────────────────────────────────
def moe_forward_bf16(hidden_states, experts, expert_ids, expert_weights):
"""Run MoE forward pass in pure BF16 (torch.matmul)."""
num_tokens, hidden_size = hidden_states.shape
top_k = expert_ids.shape[1]
output = torch.zeros(num_tokens, hidden_size, dtype=torch.bfloat16, device=DEVICE)
for t in range(num_tokens):
for k in range(top_k):
e = expert_ids[t, k].item()
w = expert_weights[t, k].item()
if e not in experts:
continue
x = hidden_states[t]
gate = x @ experts[e]["gate_proj"].T
up = x @ experts[e]["up_proj"].T
activated = torch.nn.functional.silu(gate) * up
if "down_proj" in experts[e]:
y = activated @ experts[e]["down_proj"].T
else:
y = activated[:hidden_size]
output[t] += w * y
return output
# ── CuTeDSL NVFP4 Kernel MoE Forward ──────────────────────────────────
def moe_forward_nvfp4_l1_only(slot_hidden, nvfp4_tensors, layer_idx, expert_indices, tokens_per_expert):
"""Run L1 (gate+up) GEMM using CuTeDSL.
slot_hidden is already laid out slot-major: [expert0_tokens | expert1_tokens | ...]
"""
num_slots, hidden_size = slot_hidden.shape
num_experts = len(expert_indices)
# Quantize activation
x_fp4, x_sf, x_igs = quantize_to_nvfp4(slot_hidden)
# Load and quantize weights
w_fp4_list = []
w_sf_list = []
w_gs_list = []
for e in expert_indices:
gate_w_key = f"layers.{layer_idx}.mlp.experts.{e}.gate_proj.weight"
gate_sf_key = f"layers.{layer_idx}.mlp.experts.{e}.gate_proj.weight_scale"
gate_gs_key = f"layers.{layer_idx}.mlp.experts.{e}.gate_proj.weight_scale_2"
up_w_key = f"layers.{layer_idx}.mlp.experts.{e}.up_proj.weight"
up_sf_key = f"layers.{layer_idx}.mlp.experts.{e}.up_proj.weight_scale"
up_gs_key = f"layers.{layer_idx}.mlp.experts.{e}.up_proj.weight_scale_2"
gate_w_bf16 = dequantize_nvfp4_weight(
nvfp4_tensors[gate_w_key].to(DEVICE),
nvfp4_tensors[gate_sf_key].to(DEVICE),
nvfp4_tensors[gate_gs_key].item(),
)
up_w_bf16 = dequantize_nvfp4_weight(
nvfp4_tensors[up_w_key].to(DEVICE),
nvfp4_tensors[up_sf_key].to(DEVICE),
nvfp4_tensors[up_gs_key].item(),
)
# Fuse gate + up, transpose to (K=hidden, N=6144)
fused = torch.cat([gate_w_bf16, up_w_bf16], dim=0) # (6144, 7168)
l1_w_bf16 = fused.T # (7168, 6144)
l1_w_fp4, l1_w_sf, l1_w_gs = quantize_weight_to_nvfp4(l1_w_bf16)
w_fp4_list.append(l1_w_fp4)
w_sf_list.append(l1_w_sf)
w_gs_list.append(l1_w_gs)
# Stack and convert to K-major
mat_b = make_b_k_major(torch.stack(w_fp4_list))
# Assemble scale factors
# scale_a: per-expert activation scales, split by expert offsets
x_sf_parts = []
offset = 0
for tpe in tokens_per_expert:
x_sf_parts.append(x_sf[offset:offset+tpe])
offset += tpe
scale_a = assemble_scales_2d_side(x_sf_parts)
scale_b = assemble_scales_3d_side(w_sf_list)
# Expert offsets
expert_offsets = compute_expert_offsets(tokens_per_expert, num_experts)
# Global scales
global_scale_a = torch.tensor([x_igs] * num_experts, dtype=torch.float32, device=DEVICE)
global_scale_b = torch.tensor(w_gs_list, dtype=torch.float32, device=DEVICE)
# Run kernel
out = run_nvfp4_grouped_gemm(
mat_a=x_fp4, mat_b=mat_b,
scale_a=scale_a, scale_b=scale_b,
expert_offsets=expert_offsets,
global_scale_a=global_scale_a, global_scale_b=global_scale_b,
)
return out
def main():
torch.manual_seed(42)
expert_indices = [0, 1, 2]
top_k = 2
num_tokens = 4
hidden_size = 7168
# ── Load NVFP4 checkpoint ──
print("=" * 70)
print(" Loading NVFP4 checkpoint layer 0")
print("=" * 70)
nvfp4_tensors = load_layer_tensors(NVFP4_MODEL_DIR, LAYER_IDX)
expert_keys = [k for k in sorted(nvfp4_tensors.keys()) if 'experts.0.' in k]
print(f" {len(nvfp4_tensors)} tensors loaded")
for key in expert_keys[:3]:
t = nvfp4_tensors[key]
print(f" {key}: dtype={t.dtype} shape={tuple(t.shape)}")
# ── Prepare NVFP4 weights ──
print("
Preparing NVFP4 weights (dequant re-quant)...")
weights = prepare_nvfp4_moe_weights(nvfp4_tensors, LAYER_IDX, expert_indices)
print(f" L1: {len(weights['l1_fp4'])} experts, shape {weights['l1_fp4'][0].shape}")
print(f" L2: {len(weights['l2_fp4'])} experts, shape {weights['l2_fp4'][0].shape}")
# ── Dequantize → BF16 reference ──
print("
Dequantizing NVFP4 BF16 reference...")
nvfp4_experts_bf16 = dequantize_nvfp4_experts(nvfp4_tensors, LAYER_IDX, expert_indices)
# ── Create test input ──
hidden_states = torch.randn(num_tokens, hidden_size, dtype=torch.bfloat16, device=DEVICE) * 2.0
expert_ids = torch.tensor([[0, 1]] * num_tokens, dtype=torch.int32, device=DEVICE)
expert_weights = torch.tensor([[0.6, 0.4]] * num_tokens, dtype=torch.float32, device=DEVICE)
# ── BF16 full MoE reference ──
print("
Running BF16 MoE reference...")
ref_output = moe_forward_bf16(hidden_states, nvfp4_experts_bf16, expert_ids, expert_weights)
print(f" BF16 ref: amax={ref_output.abs().max():.4f} mean={ref_output.float().mean():.6f}")
del nvfp4_experts_bf16
torch.cuda.empty_cache()
# ── CuTeDSL NVFP4 full MoE pipeline ──
print("
Running CuTeDSL NVFP4 MoE pipeline (first run compiles, ~1-2 min)...")
kernel_output = run_nvfp4_moe(
hidden_states, expert_ids, expert_weights,
weights, expert_indices,
)
print(f" Kernel: amax={kernel_output.abs().max():.4f} mean={kernel_output.float().mean():.6f}")
# ── Compare ──
cosine = torch.nn.functional.cosine_similarity(
kernel_output.flatten().unsqueeze(0).float(),
ref_output.flatten().unsqueeze(0).float(),
).item()
mse = (kernel_output.float() - ref_output.float()).pow(2).mean().item()
print(f"
{'=' * 70}")
print(f" RESULT: cosine={cosine:.6f} MSE={mse:.6e}")
print(f"{'=' * 70}")
if cosine < COSINE_THRESHOLD:
print(f" ❌ FAIL: cosine {cosine:.6f} < {COSINE_THRESHOLD}")
sys.exit(1)
else:
print(f" ✅ PASS: cosine {cosine:.6f} >= {COSINE_THRESHOLD}")
if __name__ == "__main__":
main()