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wut0n 8baf1b52b6 feat:add fused performance batchnorm+hingeloss #49 2025-12-08 16:27:09 +08:00
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import torch
from torch.utils.cpp_extension import load_inline
batchnorm_hingeloss_source = """
#include <torch/extension.h>
#include <cuda_runtime.h>
// BatchNorm + Hinge Loss 融合内核
__global__ void batchnorm_hingeloss_fused_kernel(
const float* __restrict__ input,
const float* __restrict__ target,
const float* __restrict__ weight,
const float* __restrict__ bias,
const float* __restrict__ running_mean,
const float* __restrict__ running_var,
float* __restrict__ batchnorm_output,
float* __restrict__ partial_sums,
int total_elements,
int feature_dim,
float epsilon,
float momentum,
float margin,
bool training
) {
int idx = blockIdx.x * blockDim.x + threadIdx.x;
// 局部累加器
float local_loss = 0.0f;
// 每个线程处理多个元素
int stride = blockDim.x * gridDim.x;
for (int element_idx = idx; element_idx < total_elements; element_idx += stride) {
int feature_idx = element_idx % feature_dim;
// BatchNorm标准化
float input_val = input[element_idx];
float normalized_val;
if (training) {
// 训练模式使用batch统计简化版实际需要计算batch均值和方差
float mean = running_mean[feature_idx];
float var = running_var[feature_idx];
normalized_val = (input_val - mean) / sqrtf(var + epsilon);
} else {
// 评估模式使用running统计
float mean = running_mean[feature_idx];
float var = running_var[feature_idx];
normalized_val = (input_val - mean) / sqrtf(var + epsilon);
}
// 应用权重和偏置
float batchnorm_val = normalized_val * weight[feature_idx] + bias[feature_idx];
batchnorm_output[element_idx] = batchnorm_val;
// 计算Hinge Loss: max(0, margin - y_true * y_pred)
float label = target[element_idx];
float margin_diff = margin - label * batchnorm_val;
float loss = (margin_diff > 0.0f) ? margin_diff : 0.0f;
local_loss += loss;
}
// 使用共享内存进行块内归约
extern __shared__ float shared_mem[];
shared_mem[threadIdx.x] = local_loss;
__syncthreads();
// 块内归约
for (int stride = blockDim.x / 2; stride > 0; stride /= 2) {
if (threadIdx.x < stride) {
shared_mem[threadIdx.x] += shared_mem[threadIdx.x + stride];
}
__syncthreads();
}
// 每个block写入部分和到全局内存
if (threadIdx.x == 0) {
partial_sums[blockIdx.x] = shared_mem[0];
}
}
torch::Tensor batchnorm_hingeloss_fused_cuda(
torch::Tensor input,
torch::Tensor target,
torch::Tensor weight,
torch::Tensor bias,
torch::Tensor running_mean,
torch::Tensor running_var,
float epsilon = 1e-5,
float momentum = 0.1,
float margin = 1.0,
bool training = false
) {
TORCH_CHECK(input.scalar_type() == torch::kFloat32, "Input must be float32");
TORCH_CHECK(target.scalar_type() == torch::kFloat32, "Target must be float32");
TORCH_CHECK(weight.scalar_type() == torch::kFloat32, "Weight must be float32");
TORCH_CHECK(bias.scalar_type() == torch::kFloat32, "Bias must be float32");
TORCH_CHECK(running_mean.scalar_type() == torch::kFloat32, "Running mean must be float32");
TORCH_CHECK(running_var.scalar_type() == torch::kFloat32, "Running var must be float32");
TORCH_CHECK(input.sizes() == target.sizes(), "Input and target must have same shape");
auto input_contig = input.contiguous();
auto target_contig = target.contiguous();
auto weight_contig = weight.contiguous();
auto bias_contig = bias.contiguous();
auto running_mean_contig = running_mean.contiguous();
auto running_var_contig = running_var.contiguous();
int total_elements = input_contig.numel();
int feature_dim = weight_contig.numel();
// 动态块分配
int num_blocks;
if (total_elements <= 2048) {
num_blocks = 4;
} else if (total_elements <= 8192) {
num_blocks = 8;
} else if (total_elements <= 32768) {
num_blocks = 16;
} else if (total_elements <= 131072) {
num_blocks = 32;
} else {
num_blocks = 64;
}
// 创建BatchNorm输出和部分和数组
auto batchnorm_output = torch::empty_like(input_contig);
auto partial_sums = torch::zeros({num_blocks}, input.options());
size_t shared_mem = 256 * sizeof(float);
batchnorm_hingeloss_fused_kernel<<<num_blocks, 256, shared_mem>>>(
input_contig.data_ptr<float>(),
target_contig.data_ptr<float>(),
weight_contig.data_ptr<float>(),
bias_contig.data_ptr<float>(),
running_mean_contig.data_ptr<float>(),
running_var_contig.data_ptr<float>(),
batchnorm_output.data_ptr<float>(),
partial_sums.data_ptr<float>(),
total_elements,
feature_dim,
epsilon,
momentum,
margin,
training
);
// 在GPU上完成最终归约
auto total_loss = torch::sum(partial_sums);
return total_loss;
}
"""
batchnorm_hingeloss_cpp_source = """
torch::Tensor batchnorm_hingeloss_fused_cuda(torch::Tensor input, torch::Tensor target, torch::Tensor weight, torch::Tensor bias, torch::Tensor running_mean, torch::Tensor running_var, float epsilon, float momentum, float margin, bool training);
"""
# 编译CUDA代码
batchnorm_hingeloss = load_inline(
name="batchnorm_hingeloss",
cpp_sources=batchnorm_hingeloss_cpp_source,
cuda_sources=batchnorm_hingeloss_source,
functions=["batchnorm_hingeloss_fused_cuda"],
extra_cuda_cflags=[
"-O3",
"--use_fast_math",
"-gencode=arch=compute_80,code=sm_80"
],
verbose=True
)
class ModelNew(torch.nn.Module):
def __init__(self, num_features, epsilon=1e-5, momentum=0.1, margin=1.0):
super(ModelNew, self).__init__()
self.num_features = num_features
self.epsilon = epsilon
self.momentum = momentum
self.margin = margin
self.batchnorm_hingeloss = batchnorm_hingeloss
def forward(self, input, target, weight, bias, running_mean, running_var, training=False):
return self.batchnorm_hingeloss.batchnorm_hingeloss_fused_cuda(
input, target, weight, bias, running_mean, running_var,
self.epsilon, self.momentum, self.margin, training
)

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import torch
import torch.nn as nn
class Model(nn.Module):
"""
BatchNorm + Hinge Loss融合基准
"""
def __init__(self, num_features, epsilon=1e-5, momentum=0.1, margin=1.0):
super(Model, self).__init__()
self.num_features = num_features
self.epsilon = epsilon
self.momentum = momentum
self.margin = margin
def forward(self, input: torch.Tensor, target: torch.Tensor, weight: torch.Tensor, bias: torch.Tensor,
running_mean: torch.Tensor, running_var: torch.Tensor, training: bool = False) -> torch.Tensor:
"""
融合计算BatchNorm和Hinge Loss
Args:
input (torch.Tensor): 输入张量
target (torch.Tensor): 目标标签
weight (torch.Tensor): BatchNorm权重
bias (torch.Tensor): BatchNorm偏置
running_mean (torch.Tensor): 运行均值
running_var (torch.Tensor): 运行方差
training (bool): 是否为训练模式
Returns:
torch.Tensor: Hinge Loss标量值
"""
# BatchNorm计算
batchnorm_output = torch.nn.functional.batch_norm(
input, running_mean, running_var, weight, bias,
training=training, momentum=self.momentum, eps=self.epsilon
)
# Hinge Loss计算
hinge_loss = torch.clamp(self.margin - target * batchnorm_output, min=0)
return torch.sum(hinge_loss)
batch_size = 256
num_features = 512
margin = 1.0
def get_inputs():
"""生成测试数据"""
input = torch.randn(batch_size, num_features)
target = torch.randint(-1, 2, (batch_size, num_features)).float()
target[target == 0] = 1 # 确保标签为-1或1
# BatchNorm参数
weight = torch.randn(num_features)
bias = torch.randn(num_features)
running_mean = torch.zeros(num_features)
running_var = torch.ones(num_features)
return [input, target, weight, bias, running_mean, running_var]
def get_init_inputs():
return [num_features]

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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.
**SPECIAL INSTRUCTIONS FOR REDUCTION-INTENSIVE OPERATORS (Loss Functions):**
When the target operator involves reduction operations that sum across tensor dimensions (like loss functions), you MUST implement the following optimized strategy:
1. **TWO-LEVEL REDUCTION APPROACH**: Instead of using atomic operations on the final result, implement:
- **Level 1**: Block-level reduction using shared memory
- **Level 2**: Final reduction on GPU using torch.sum() on partial results
- This eliminates atomic operation contention for large tensors
2. **SHARED MEMORY REDUCTION PATTERN**:
cpp
// Each thread accumulates locally
float local_loss = 0.0f;
for (int element_idx = idx; element_idx < total_elements; element_idx += stride) {
// Compute loss for each element
local_loss += computed_loss;
}
// Block-level reduction using shared memory
extern __shared__ float shared_mem[];
shared_mem[threadIdx.x] = local_loss;
__syncthreads();
// Reduction within block
for (int stride = blockDim.x / 2; stride > 0; stride /= 2) {
if (threadIdx.x < stride) {
shared_mem[threadIdx.x] += shared_mem[threadIdx.x + stride];
}
__syncthreads();
}
// Each block writes partial sum
if (threadIdx.x == 0) {
partial_sums[blockIdx.x] = shared_mem[0];
}
3. **DYNAMIC BLOCK ALLOCATION**: Based on total_elements:
cpp
int num_blocks;
if (total_elements <= 2048) num_blocks = 4;
else if (total_elements <= 8192) num_blocks = 8;
else if (total_elements <= 32768) num_blocks = 16;
else if (total_elements <= 131072) num_blocks = 32;
else num_blocks = 64;
4. **ELEMENT PROCESSING STRATEGY**: Each thread processes multiple elements:
cpp
int stride = blockDim.x * gridDim.x;
for (int element_idx = idx; element_idx < total_elements; element_idx += stride) {
// Process element at element_idx
}
5. **FINAL REDUCTION ON GPU**: Use torch.sum() on partial results:
cpp
auto partial_sums = torch::zeros({num_blocks}, input.options());
// … kernel execution …
auto total_loss = torch::sum(partial_sums);
return total_loss;
6. **COMPILATION FLAGS**: Use balanced optimization:
python
extra_cuda_cflags=[
"-O3",
"use_fast_math",
"-gencode=arch=compute_80,code=sm_80"
]
7. **PRECISION REQUIREMENTS**: Ensure exact mathematical alignment:
- Use same mathematical formulas as PyTorch implementation
- Verify with torch.allclose(rtol=1e-03, atol=1e-6)
- Test with different input sizes
8. **FUSION OPTIMIZATION FOR BatchNorm+Hinge Loss**:
- Compute BatchNorm normalization first: `(input - mean) / sqrt(var + epsilon)`
- Apply weight and bias: `normalized * weight + bias`
- Store BatchNorm output to separate tensor
- Compute Hinge Loss on BatchNorm output: `max(0, margin - y_true * batchnorm_val)`
- Single kernel eliminates intermediate tensor storage
- Process both operations in one memory access pass
- Handle both training and evaluation modes correctly
Here's the target architecture to optimize:
python
import torch
import torch.nn as nn
class Model(nn.Module):
"""
BatchNorm + Hinge Loss fusion implementation.
Computes BatchNorm normalization first, then applies hinge loss on normalized values.
"""
def init(self, num_features, epsilon=1e-5, momentum=0.1, margin=1.0):
super(Model, self).init()
self.num_features = num_features
self.epsilon = epsilon
self.momentum = momentum
self.margin = margin
def forward(self, input: torch.Tensor, target: torch.Tensor, weight: torch.Tensor, bias: torch.Tensor,
running_mean: torch.Tensor, running_var: torch.Tensor, training: bool = False) -> torch.Tensor:
"""
Compute BatchNorm normalization followed by hinge loss.
Args:
input (torch.Tensor): Input tensor
target (torch.Tensor): Target labels (should be -1 or 1)
weight (torch.Tensor): BatchNorm weight
bias (torch.Tensor): BatchNorm bias
running_mean (torch.Tensor): Running mean statistics
running_var (torch.Tensor): Running variance statistics
training (bool): Whether in training mode
Returns:
torch.Tensor: Scalar hinge loss value computed on BatchNorm output
"""
# BatchNorm computation
batchnorm_output = torch.nn.functional.batch_norm(
input, running_mean, running_var, weight, bias,
training=training, momentum=self.momentum, eps=self.epsilon
)
# Hinge Loss: max(0, margin - y_true * y_pred) computed on BatchNorm output
hinge_loss = torch.clamp(self.margin - target * batchnorm_output, min=0)
return torch.sum(hinge_loss)
batch_size = 256
num_features = 512
margin = 1.0
def get_inputs():
input = torch.randn(batch_size, num_features)
target = torch.randint(-1, 2, (batch_size, num_features)).float()
target[target == 0] = 1 # Ensure labels are -1 or 1
# BatchNorm parameters
weight = torch.randn(num_features)
bias = torch.randn(num_features)
running_mean = torch.zeros(num_features)
running_var = torch.ones(num_features)
return [input, target, weight, bias, running_mean, running_var]
def get_init_inputs():
return [num_features] # num_features parameter
**EXPECTED OUTPUT STRUCTURE**:
Generate two files:
1. `batchnorm_hingeloss_cudacode.py` - Contains ModelNew class with BatchNorm+Hinge fusion using two-level reduction approach
2. `batchnorm_hingeloss_torchcode.py` - Contains the reference PyTorch implementation
**KEY REQUIREMENTS**:
- The CUDA implementation must use two-level reduction to avoid atomic operation bottlenecks
- Must implement exact fusion: BatchNorm normalization first, then Hinge Loss on normalized values
- Must use shared memory for block-level reduction
- Must use dynamic block allocation based on input size
- Must complete final reduction with torch.sum() on GPU
- Must maintain mathematical precision with PyTorch implementation
- Must handle arbitrary tensor shapes
- Must store BatchNorm output to separate tensor for potential further use
- Target labels should be -1 or 1, ensure proper handling in the kernel
- Fusion must eliminate intermediate tensor storage between BatchNorm and Hinge Loss
- Must correctly handle both training and evaluation modes
- Must apply epsilon for numerical stability in BatchNorm

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S1/wut0n_#49/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 batchnorm_hingeloss_torchcode import Model, get_inputs, get_init_inputs
from batchnorm_hingeloss_cudacode 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 batchnorm_hingeloss 平均执行时间: {torch_time:.6f}")
print(f"自定义 CUDA batchnorm_hingeloss 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()