Files
nvfp4-megamoe-kernel/tests/layertest.py
biondizzle a0ff8a3278 fix: transpose checkpoint block scales (N,K_sf)→(K_sf,N) for bridge
The bridge's assemble_scales_3d_side expects (K_sf, N) input and
transposes to (N, K_sf) internally before swizzling. The checkpoint
stores scales as (N, K_sf). Without this transpose, the kernel was
reading completely wrong scale data — cosine dropped to 0.713.

Also fixed dual global scale normalization: after transpose, gate/up
are along dim 1 (columns), not dim 0 (rows).
2026-05-16 03:43:30 +00:00

257 lines
10 KiB
Python

#!/usr/bin/env python3
"""
Layer 0 full MoE pipeline test: CuTeDSL NVFP4 vs BF16 reference.
Tests the complete pipeline: L1→SiLU→L2→scatter
If cosine < 0.99, exits with error.
"""
import os
import sys
import json
import glob
import torch
from safetensors import safe_open
REPO_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
sys.path.insert(0, REPO_ROOT)
from cutedsl.moe_pipeline import (
run_nvfp4_moe,
)
NVFP4_MODEL_DIR = "/root/nvidia-meeting/DeepSeek-V4-Pro-NVFP4"
LAYER_IDX = 0
DEVICE = "cuda"
COSINE_THRESHOLD = 0.98 # Double quantization loss from checkpoint dequant→requant
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)
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):
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
def dequantize_nvfp4_weight(packed_uint8, scale_e4m3, global_scale):
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):
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
def moe_forward_bf16(hidden_states, experts, expert_ids, expert_weights):
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
def prepare_nvfp4_weights_direct(nvfp4_tensors, layer_idx, expert_indices, intermediate_size):
"""Prepare weights via direct view-cast (no BF16 round-trip).
Checkpoint uint8 → float4_e2m1fn_x2 (byte-preserving).
Block scales float8_e4m3fn → used directly.
Global scales float32 → used directly.
For L1 (gate+up fused): normalize dual global scales to max, fold ratio
into block scales via float32 (one multiply + float8 round-trip on ratio only).
"""
l1_fp4, l1_sf, l1_gs = [], [], []
l2_fp4, l2_sf, l2_gs = [], [], []
for e in expert_indices:
# L1: gate + up
gate_w = nvfp4_tensors[f"layers.{layer_idx}.mlp.experts.{e}.gate_proj.weight"].to(DEVICE)
up_w = nvfp4_tensors[f"layers.{layer_idx}.mlp.experts.{e}.up_proj.weight"].to(DEVICE)
gate_sf = nvfp4_tensors[f"layers.{layer_idx}.mlp.experts.{e}.gate_proj.weight_scale"].to(DEVICE)
up_sf = nvfp4_tensors[f"layers.{layer_idx}.mlp.experts.{e}.up_proj.weight_scale"].to(DEVICE)
gate_gs = nvfp4_tensors[f"layers.{layer_idx}.mlp.experts.{e}.gate_proj.weight_scale_2"].item()
up_gs = nvfp4_tensors[f"layers.{layer_idx}.mlp.experts.{e}.up_proj.weight_scale_2"].item()
# Fuse gate+up along N, transpose to K-major
fused_w = torch.cat([gate_w, up_w], dim=0) # (2*intermediate, hidden//2) uint8
fused_w_fp4 = fused_w.view(torch.float4_e2m1fn_x2).permute(1, 0).contiguous()
# (hidden//2, 2*intermediate) — K=hidden packed, N=2*intermediate
# Fuse block scales: checkpoint is (N, K_sf), bridge expects (K_sf, N)
fused_sf = torch.cat([gate_sf, up_sf], dim=0) # (2*intermediate, hidden//16) = (N, K_sf)
fused_sf = fused_sf.permute(1, 0).contiguous() # → (K_sf, N)
# Normalize dual global scales
l1_max_gs = max(gate_gs, up_gs)
if gate_gs != up_gs:
fused_sf_f32 = fused_sf.float()
# Gate is first intermediate cols, up is second (after transpose)
fused_sf_f32[:, :intermediate_size] *= (gate_gs / l1_max_gs)
fused_sf_f32[:, intermediate_size:] *= (up_gs / l1_max_gs)
fused_sf = fused_sf_f32.to(torch.float8_e4m3fn)
l1_fp4.append(fused_w_fp4)
l1_sf.append(fused_sf)
l1_gs.append(l1_max_gs)
# L2: down
down_key = f"layers.{layer_idx}.mlp.experts.{e}.down_proj.weight"
if down_key in nvfp4_tensors:
down_w = nvfp4_tensors[down_key].to(DEVICE)
down_sf = nvfp4_tensors[f"layers.{layer_idx}.mlp.experts.{e}.down_proj.weight_scale"].to(DEVICE)
down_gs = nvfp4_tensors[f"layers.{layer_idx}.mlp.experts.{e}.down_proj.weight_scale_2"].item()
down_w_fp4 = down_w.view(torch.float4_e2m1fn_x2).permute(1, 0).contiguous()
# (intermediate//2, hidden) — K=intermediate packed, N=hidden
l2_fp4.append(down_w_fp4)
l2_sf.append(down_sf.permute(1, 0).contiguous()) # (N, K_sf) → (K_sf, N)
l2_gs.append(down_gs)
else:
# Expert 211 has no down_proj
l2_fp4.append(torch.zeros(3072 // 2, 7168, dtype=torch.float4_e2m1fn_x2, device=DEVICE))
l2_sf.append(torch.ones(3072 // 16, 7168, dtype=torch.float8_e4m3fn, device=DEVICE)) # (K_sf, N)
l2_gs.append(1.0)
return {
'l1_fp4': l1_fp4, 'l1_sf': l1_sf, 'l1_gs': l1_gs,
'l2_fp4': l2_fp4, 'l2_sf': l2_sf, 'l2_gs': l2_gs,
}
def main():
torch.manual_seed(42)
expert_indices = [0, 1, 2]
top_k = 2
num_tokens = 4
hidden_size = 7168
print("=" * 70)
print(" Loading NVFP4 checkpoint layer 0")
print("=" * 70)
nvfp4_tensors = load_layer_tensors(NVFP4_MODEL_DIR, LAYER_IDX)
print(f" {len(nvfp4_tensors)} tensors loaded")
# Prepare weights — DIRECT PATH (no BF16 round-trip)
print("\n Preparing NVFP4 weights (direct view-cast)...")
weights = prepare_nvfp4_weights_direct(nvfp4_tensors, LAYER_IDX, expert_indices, 3072)
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 for BF16 reference
print("\n Dequantizing NVFP4 -> BF16 reference...")
nvfp4_experts_bf16 = dequantize_nvfp4_experts(nvfp4_tensors, LAYER_IDX, expert_indices)
# 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 reference
print("\n 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 pipeline
print("\n Running CuTeDSL NVFP4 MoE pipeline (first run compiles)...")
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"\n{'=' * 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()