Merge pull request 'finish CrossLayerNorm #136' (#788) from ZZZJ/GPUCodeForces:CrossLayerNorm into main

This commit is contained in:
wawahejun 2025-12-14 20:35:18 +08:00
commit e409972e99
4 changed files with 293 additions and 0 deletions

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import torch
import torch.nn as nn
from torch.utils.cpp_extension import load_inline
class ModelNew(nn.Module):
def __init__(self):
super().__init__()
self.hidden_dim = 4096
self.weight = nn.Parameter(torch.ones(self.hidden_dim, device='cuda'))
self.eps = 1e-6
self._compile_cuda_kernel()
def _compile_cuda_kernel(self):
cpp_source = """
#include <torch/extension.h>
torch::Tensor cross_ln_cuda(torch::Tensor x, torch::Tensor res, torch::Tensor weight, float eps);
"""
cuda_source = """
#include <cuda_runtime.h>
#define BLOCK_SIZE 256
// Warp Reduce
__device__ __forceinline__ float warpReduceSum(float val) {
#pragma unroll
for (int offset = 16; offset > 0; offset /= 2)
val += __shfl_down_sync(0xffffffff, val, offset);
return val;
}
// Block Reduce
__device__ __forceinline__ float blockReduceSum(float val) {
static __shared__ float shared[32];
int lane = threadIdx.x % 32;
int wid = threadIdx.x / 32;
val = warpReduceSum(val);
if (lane == 0) shared[wid] = val;
__syncthreads();
val = (threadIdx.x < blockDim.x / 32) ? shared[lane] : 0.0f;
if (wid == 0) val = warpReduceSum(val);
return val;
}
// Fused Kernel: Add + RMSNorm with Float4
__global__ void cross_ln_f4_kernel(
const float* __restrict__ x,
const float* __restrict__ res,
const float* __restrict__ weight,
float* __restrict__ output,
int hidden_dim,
int n_vec, // hidden_dim / 4
float eps
) {
// Grid.x = Batch (Rows)
int row_idx = blockIdx.x;
int tid = threadIdx.x;
int offset = row_idx * hidden_dim;
const float4* x_ptr = reinterpret_cast<const float4*>(x + offset);
const float4* res_ptr = reinterpret_cast<const float4*>(res + offset);
const float4* w_ptr = reinterpret_cast<const float4*>(weight);
float4* out_ptr = reinterpret_cast<float4*>(output + offset);
// --- Pass 1: Sum of Squares (Compute Variance) ---
float sum_sq = 0.0f;
for (int i = tid; i < n_vec; i += BLOCK_SIZE) {
float4 vx = x_ptr[i];
float4 vr = res_ptr[i];
// Fused Add
float v0 = vx.x + vr.x;
float v1 = vx.y + vr.y;
float v2 = vx.z + vr.z;
float v3 = vx.w + vr.w;
// Accumulate Square
sum_sq += v0*v0 + v1*v1 + v2*v2 + v3*v3;
}
// Block Reduction
sum_sq = blockReduceSum(sum_sq);
// Broadcast Rsqrt
__shared__ float rscale;
if (tid == 0) {
rscale = rsqrtf(sum_sq / (float)hidden_dim + eps);
}
__syncthreads();
float scale = rscale;
// --- Pass 2: Normalize and Write ---
for (int i = tid; i < n_vec; i += BLOCK_SIZE) {
float4 vx = x_ptr[i];
float4 vr = res_ptr[i];
float4 w = w_ptr[i];
float4 out;
// Re-compute Add & Normalize
out.x = (vx.x + vr.x) * scale * w.x;
out.y = (vx.y + vr.y) * scale * w.y;
out.z = (vx.z + vr.z) * scale * w.z;
out.w = (vx.w + vr.w) * scale * w.w;
// Write
out_ptr[i] = out;
}
}
torch::Tensor cross_ln_cuda(torch::Tensor x, torch::Tensor res, torch::Tensor weight, float eps) {
int batch_seq = x.size(0);
int hidden_dim = x.size(1);
auto output = torch::empty_like(x);
if (hidden_dim % 4 != 0) return output;
int n_vec = hidden_dim / 4;
// Grid = Batch Size, Block = 256
cross_ln_f4_kernel<<<batch_seq, BLOCK_SIZE>>>(
x.data_ptr<float>(),
res.data_ptr<float>(),
weight.data_ptr<float>(),
output.data_ptr<float>(),
hidden_dim,
n_vec,
eps
);
return output;
}
"""
self.op = load_inline(
name="cross_ln_f4_optimized_v2",
cpp_sources=cpp_source,
cuda_sources=cuda_source,
functions=["cross_ln_cuda"],
extra_cuda_cflags=["-O3", "--use_fast_math"],
verbose=False
)
def forward(self, x: torch.Tensor, residual: torch.Tensor) -> torch.Tensor:
if not x.is_contiguous(): x = x.contiguous()
if not residual.is_contiguous(): residual = residual.contiguous()
return self.op.cross_ln_cuda(x, residual, self.weight, self.eps)

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import torch
import torch.nn as nn
BATCH_SEQ = 8192
HIDDEN_DIM = 4096
class Model(nn.Module):
def __init__(self):
super().__init__()
self.weight = nn.Parameter(torch.ones(HIDDEN_DIM))
self.eps = 1e-6
def forward(self, x: torch.Tensor, residual: torch.Tensor) -> torch.Tensor:
added = x + residual
input_dtype = added.dtype
added_f32 = added.to(torch.float32)
variance = added_f32.pow(2).mean(-1, keepdim=True)
hidden_states = added_f32 * torch.rsqrt(variance + self.eps)
return self.weight * hidden_states.to(input_dtype)
def get_inputs():
x = torch.randn(BATCH_SEQ, HIDDEN_DIM, device='cuda', dtype=torch.float32)
res = torch.randn(BATCH_SEQ, HIDDEN_DIM, device='cuda', dtype=torch.float32)
return [x, res]
def get_init_inputs():
return []

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S1/ZZZJ_#136/prompt.txt Normal file
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You write custom CUDA kernels to replace the pytorch operators in the given architecture to get speedups.
You have complete freedom to choose the set of operators you want to replace. You may make the decision to replace some operators with custom CUDA kernels and leave others unchanged. You may replace multiple operators with custom implementations, consider operator fusion opportunities (combining multiple operators into a single kernel, for example, combining matmul+relu), or algorithmic changes (such as online softmax). You are only limited by your imagination.
Here's an example to show you the syntax of inline embedding custom CUDA operators in torch: The example given architecture is:
python
import torch
import torch.nn as nn
BATCH_SEQ = 8192
HIDDEN_DIM = 4096
class Model(nn.Module):
def __init__(self):
super().__init__()
self.weight = nn.Parameter(torch.ones(HIDDEN_DIM))
self.eps = 1e-6
def forward(self, x: torch.Tensor, residual: torch.Tensor) -> torch.Tensor:
added = x + residual
input_dtype = added.dtype
added_f32 = added.to(torch.float32)
variance = added_f32.pow(2).mean(-1, keepdim=True)
hidden_states = added_f32 * torch.rsqrt(variance + self.eps)
return self.weight * hidden_states.to(input_dtype)
def get_inputs():
x = torch.randn(BATCH_SEQ, HIDDEN_DIM, device='cuda', dtype=torch.float32)
res = torch.randn(BATCH_SEQ, HIDDEN_DIM, device='cuda', dtype=torch.float32)
return [x, res]
def get_init_inputs():
return []
```

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S1/ZZZJ_#136/run_code.py Normal file
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###########################################################
# 性能和精度验证程序
###########################################################
import torch
import torch.nn as nn
import time
from cross_layer_norm_torch import Model,get_inputs,get_init_inputs
from cross_layer_norm_cuda import ModelNew
def run_benchmark():
# 检查 CUDA 是否可用
if not torch.cuda.is_available():
print("CUDA 不可用,请确保您有可用的 NVIDIA GPU 并已正确安装 PyTorch CUDA 版本。")
return
else:
device = torch.device("cuda")
# 初始化模型
init_inputs = get_init_inputs()
init_inputs = [
x.cuda(device=device) if isinstance(x, torch.Tensor) else x for x in init_inputs
]
inputs = get_inputs()
inputs = [
x.cuda(device=device) if isinstance(x, torch.Tensor) else x for x in inputs
]
torch_model = Model(*init_inputs).cuda()
cuda_model = ModelNew(*init_inputs).cuda()
torch_model.eval()
cuda_model.eval()
print("-------------------- 精度对齐验证 --------------------")
with torch.no_grad():
output_torch = torch_model( *inputs)
output_cuda = cuda_model(*inputs)
precision_flag = torch.allclose(output_torch, output_cuda,rtol=1e-03)
if precision_flag:
print("✅ 精度对齐:两个模型的输出结果非常接近。")
else:
print("❌ 精度不一致!")
print("\n-------------------- 性能加速比测试 --------------------")
num_iterations = 100
# PyTorch 模型计时
torch.cuda.synchronize()
start_time = time.time()
for _ in range(num_iterations):
_ = torch_model(*inputs)
torch.cuda.synchronize()
torch_time = (time.time() - start_time) / num_iterations
# 自定义 CUDA 内核计时
torch.cuda.synchronize()
start_time = time.time()
for _ in range(num_iterations):
_ = cuda_model(*inputs)
torch.cuda.synchronize()
cuda_time = (time.time() - start_time) / num_iterations
print(f"PyTorch torch.relu 平均执行时间: {torch_time:.6f}")
print(f"自定义 CUDA 内核 平均执行时间: {cuda_time:.6f}")
speedup = 0
if cuda_time > 0:
speedup = torch_time / cuda_time
print(f"加速比 (Speedup): {speedup:.2f}x")
else:
print("CUDA 内核执行时间为0无法计算加速比。")
return precision_flag,speedup
if __name__ == "__main__":
precision_flag,speedup = run_benchmark()