finish Smelu #48

This commit is contained in:
uucoco 2025-12-02 21:38:59 +08:00
parent 10eed82956
commit 96570c5db2
4 changed files with 277 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, beta=2.0):
super().__init__()
self.beta = beta
self._compile_cuda_kernel()
def _compile_cuda_kernel(self):
cpp_source = """
#include <torch/extension.h>
torch::Tensor smelu_cuda(torch::Tensor x, float beta);
"""
cuda_source = """
#include <cuda_runtime.h>
__device__ __forceinline__ float smelu_op(float x, float beta, float inv_4beta) {
float abs_x = fabsf(x);
if (abs_x < beta) {
float tmp = x + beta;
return tmp * tmp * inv_4beta;
} else {
return (x > 0.0f) ? x : 0.0f;
}
}
__global__ void smelu_kernel_vec4(
const float* __restrict__ x,
float* __restrict__ y,
int n,
float beta,
float inv_4beta)
{
int idx = blockIdx.x * blockDim.x + threadIdx.x;
int stride = blockDim.x * gridDim.x;
int vec_n = n / 4;
const float4* x_vec = reinterpret_cast<const float4*>(x);
float4* y_vec = reinterpret_cast<float4*>(y);
for (int i = idx; i < vec_n; i += stride) {
float4 v = x_vec[i];
float4 out;
out.x = smelu_op(v.x, beta, inv_4beta);
out.y = smelu_op(v.y, beta, inv_4beta);
out.z = smelu_op(v.z, beta, inv_4beta);
out.w = smelu_op(v.w, beta, inv_4beta);
y_vec[i] = out;
}
int tail = vec_n * 4;
for (int i = tail + idx; i < n; i += stride) {
y[i] = smelu_op(x[i], beta, inv_4beta);
}
}
torch::Tensor smelu_cuda(torch::Tensor x, float beta) {
auto x_c = x.contiguous();
auto output = torch::empty_like(x_c);
int n = x_c.numel();
int threads = 256;
int blocks = (n / 4 + threads - 1) / threads;
if (blocks > 65535) blocks = 65535;
if (blocks == 0) blocks = 1;
float inv_4beta = 1.0f / (4.0f * beta);
smelu_kernel_vec4<<<blocks, threads>>>(
x_c.data_ptr<float>(),
output.data_ptr<float>(),
n,
beta,
inv_4beta
);
return output;
}
"""
self.op = load_inline(
name="smelu_opt_vec4",
cpp_sources=cpp_source,
cuda_sources=cuda_source,
functions=["smelu_cuda"],
extra_cuda_cflags=["-O3", "--use_fast_math"],
verbose=False
)
def forward(self, x):
return self.op.smelu_cuda(x, self.beta)

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import torch
import torch.nn as nn
import torch.nn.functional as F
class Model(nn.Module):
def __init__(self, beta=2.0):
super().__init__()
self.beta = beta
def forward(self, x: torch.Tensor) -> torch.Tensor:
abs_x = torch.abs(x)
return torch.where(
abs_x < self.beta,
torch.pow(x + self.beta, 2) / (4.0 * self.beta),
F.relu(x)
)
batch_size = 128
feature_dim = 1024
def get_inputs():
x = torch.randn(batch_size, feature_dim, dtype=torch.float32)
return [x]
def get_init_inputs():
return [2.0]

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S1/uucoco_#48/prompt.txt Normal file
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You write custom CUDA kernels to replace the pytorch operators in the given GeGLU 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 chunk+gelu+elementwise_mul), or algorithmic changes (such as optimized memory access patterns). You are only limited by your imagination.
This CUDA kernel implements optimized Smooth ReLU (SmeLU) activation with:
Memory Optimization:
Vectorized memory access using float4 for 4x bandwidth
Contiguous tensor inputs for coalesced memory access
Separate handling for vectorized main loop and scalar tail
Parallelization Strategy:
Grid-stride loop for efficient workload distribution
256 threads per block optimal configuration
Automatic grid size calculation with 65535 block limit
Computational Optimization:
SmeLU activation with configurable beta parameter
Precomputed reciprocal: inv_4beta = 1.0f / (4.0f * beta)
Fast math compilation flags for optimized arithmetic
Branching implementation:
For |x| < beta: (x + beta)² / (4 * beta)
For x ≥ beta: x
For x ≤ -beta: 0
Work Distribution:
Vectorized main loop processes 4 elements per thread via float4
Scalar tail handles remaining elements (n % 4)
Each thread computes independent SmeLU operations
The implementation provides maximum throughput through vectorization while maintaining the smooth transition characteristic of SmeLU activation with configurable beta parameter.
Here's an example to show you the syntax of inline embedding custom CUDA operators in torch: The example given architecture is:
import torch
import torch.nn as nn
import torch.nn.functional as F
class Model(nn.Module):
def __init__(self, beta=2.0):
super().__init__()
self.beta = beta
def forward(self, x: torch.Tensor) -> torch.Tensor:
abs_x = torch.abs(x)
return torch.where(
abs_x < self.beta,
torch.pow(x + self.beta, 2) / (4.0 * self.beta),
F.relu(x)
)
batch_size = 128
feature_dim = 1024
def get_inputs():
x = torch.randn(batch_size, feature_dim, dtype=torch.float32)
return [x]
def get_init_inputs():
return [2

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S1/uucoco_#48/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 SmeLU_torch import Model, get_inputs, get_init_inputs
from SmeLU_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()