Merge pull request 'finish Elish #35' (#286) from gsd123/GPUCodeForces:gsd35 into main

This commit is contained in:
Kuohais 2025-12-04 14:55:54 +08:00
commit 4e3c2aff4d
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):
super().__init__()
self._compile_cuda_kernel()
def _compile_cuda_kernel(self):
cpp_source = """
torch::Tensor elish_cuda(torch::Tensor x);
"""
cuda_source = """
#include <torch/extension.h>
#include <cuda_runtime.h>
#include <math.h>
__device__ __forceinline__ float elish_op(float x) {
// Sigmoid: 1 / (1 + exp(-x))
float sigmoid_val = 1.0f / (1.0f + expf(-x));
// ELU: x if x >= 0 else (exp(x) - 1)
// 使用 expm1f(x) 计算 exp(x) - 1 可以获得更高的精度
float elu_val = (x >= 0.0f) ? x : expm1f(x);
return elu_val * sigmoid_val;
}
__global__ void elish_kernel(
const float* __restrict__ x,
float* __restrict__ output,
const int n_elements)
{
const int tid = blockIdx.x * blockDim.x + threadIdx.x;
const int stride = blockDim.x * gridDim.x;
const int vec_loops = n_elements >> 2;
const float4* x_vec = reinterpret_cast<const float4*>(x);
float4* out_vec = reinterpret_cast<float4*>(output);
for (int i = tid; i < vec_loops; i += stride) {
float4 v = __ldg(&x_vec[i]);
float4 r;
r.x = elish_op(v.x);
r.y = elish_op(v.y);
r.z = elish_op(v.z);
r.w = elish_op(v.w);
out_vec[i] = r;
}
const int tail_start = vec_loops << 2;
for (int i = tail_start + tid; i < n_elements; i += stride) {
output[i] = elish_op(x[i]);
}
}
torch::Tensor elish_cuda(torch::Tensor x) {
auto x_c = x.contiguous();
const int n_elements = x_c.numel();
auto output = torch::empty_like(x_c);
const int threads = 256;
const int max_blocks = 65535;
const int blocks = std::min((n_elements + threads * 4 - 1) / (threads * 4), max_blocks);
elish_kernel<<<blocks, threads>>>(
x_c.data_ptr<float>(),
output.data_ptr<float>(),
n_elements
);
return output;
}
"""
self.op = load_inline(
name="elish_v1",
cpp_sources=cpp_source,
cuda_sources=cuda_source,
functions=["elish_cuda"],
extra_cuda_cflags=["-O3", "--use_fast_math"],
verbose=False
)
def forward(self, x):
return self.op.elish_cuda(x)

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import torch
import torch.nn as nn
import torch.nn.functional as F
class Model(nn.Module):
def __init__(self):
super().__init__()
def forward(self, x: torch.Tensor) -> torch.Tensor:
# Elish = ELU(x) * Sigmoid(x)
return F.elu(x) * torch.sigmoid(x)
batch_size = 1024
feature_dim = 1024
def get_inputs():
x = torch.randn(batch_size, feature_dim, dtype=torch.float32)
return [x]
def get_init_inputs():
return []

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S1/gsd123_#35/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.
CUDA Optimization Strategies:
Vectorized Memory Access
Uses float4 for 4-element vector loads/stores
__ldg() for read-only caching through texture memory
Bit shifts for division (>> 2, << 2) for efficiency
Elish Activation Function
Computes Elish(x) = ELU(x) * Sigmoid(x)
Combination of ELU and Sigmoid activations
Requires careful numerical handling
Numerical Precision
Uses expm1f(x) for exp(x) - 1 in negative region
Higher accuracy for small x values
Standard expf(-x) for sigmoid
Memory Access
contiguous() tensors for coalescing
__restrict__ pointers
Grid-stride loop for arbitrary sizes
Performance Optimization
Compiler flags: -O3, --use_fast_math
Efficient kernel launch configuration
Block count limited to 65535
Branch for ELU (x >= 0) condition
Mathematical Efficiency
Inline ELU and Sigmoid computations
Vectorized operations for 4 elements simultaneously
Minimal conditional branching
Key Innovation: Vectorized Elish activation function combining ELU and Sigmoid, optimized with high-precision expm1f for numerical stability in the negative region.
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):
super().__init__()
def forward(self, x: torch.Tensor) -> torch.Tensor:
# Elish = ELU(x) * Sigmoid(x)
return F.elu(x) * torch.sigmoid(x)
batch_size = 1024
feature_dim = 1024
def get_inputs():
x = torch.randn(batch_size, feature_dim, dtype=torch.float32)
return [x]
def get_init_inputs():
return [

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S1/gsd123_#35/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 Elish_torch import Model, get_inputs, get_init_inputs
from Elish_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()