fixes ChannelPermute #130

This commit is contained in:
ZZZJ 2025-12-09 21:12:40 +08:00
parent cc73715277
commit fbf9a8282b
4 changed files with 222 additions and 0 deletions

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import torch
import torch.nn as nn
from torch.utils.cpp_extension import load_inline
permute_cpp_source = "torch::Tensor permute_cuda(torch::Tensor input);"
permute_cuda_source = """
#include <cuda_runtime.h>
__global__ void __launch_bounds__(256) rgb2bgr_vec_kernel(
const float* __restrict__ input,
float* __restrict__ output,
int batch_size,
int plane_size, // H * W
int vec_per_plane // plane_size / 4
) {
int idx = blockIdx.x * blockDim.x + threadIdx.x;
int total_spatial_vectors = batch_size * vec_per_plane;
if (idx >= total_spatial_vectors) return;
int batch_idx = idx / vec_per_plane;
int v_off = idx % vec_per_plane;
int base_offset = batch_idx * 3 * plane_size;
const float4* input_f4 = reinterpret_cast<const float4*>(input);
float4* output_f4 = reinterpret_cast<float4*>(output);
// float4 index = float index / 4
int r_vec_idx = (base_offset >> 2) + v_off;
int g_vec_idx = r_vec_idx + vec_per_plane;
int b_vec_idx = g_vec_idx + vec_per_plane;
float4 vec_r = input_f4[r_vec_idx];
float4 vec_g = input_f4[g_vec_idx];
float4 vec_b = input_f4[b_vec_idx];
output_f4[r_vec_idx] = vec_b; // R <- B
output_f4[g_vec_idx] = vec_g; // G <- G
output_f4[b_vec_idx] = vec_r; // B <- R
}
torch::Tensor permute_cuda(torch::Tensor input) {
int numel = input.numel();
input = input.contiguous();
auto output = torch::empty_like(input);
int batch_size = input.size(0);
int height = input.size(2);
int width = input.size(3);
int plane_size = height * width;
if (plane_size % 4 != 0) {
}
int vec_per_plane = plane_size / 4;
int total_spatial_vectors = batch_size * vec_per_plane;
const int block_size = 256;
int grid_size = (total_spatial_vectors + 255) / 256;
rgb2bgr_vec_kernel<<<grid_size, 256>>>(
input.data_ptr<float>(),
output.data_ptr<float>(),
batch_size,
plane_size,
vec_per_plane
);
return output;
}
"""
class ModelNew(nn.Module):
def __init__(self):
super().__init__()
self.module = load_inline(
name="permute_rgb2bgr_v2_fixed",
cpp_sources=permute_cpp_source,
cuda_sources=permute_cuda_source,
functions=["permute_cuda"],
verbose=False,
extra_cuda_cflags=["-O3"]
)
def forward(self, x):
return self.module.permute_cuda(x)

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import torch
import torch.nn as nn
class Model(nn.Module):
def __init__(self):
super().__init__()
self.perm_indices = [2, 1, 0]
def forward(self, img: torch.Tensor) -> torch.Tensor:
return img[:, self.perm_indices, :, :]
batch_size = 64
channels = 3
height = 1024
width = 1024
def get_inputs():
x = torch.rand(batch_size, channels, height, width, dtype=torch.float32)
return [x]
def get_init_inputs():
return []

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S1/ZZZJ_#130/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
class Model(nn.Module):
def __init__(self):
super().__init__()
self.perm_indices = [2, 1, 0]
def forward(self, img: torch.Tensor) -> torch.Tensor:
return img[:, self.perm_indices, :, :]
batch_size = 64
channels = 3
height = 1024
width = 1024
def get_inputs():
x = torch.rand(batch_size, channels, height, width, dtype=torch.float32)
return [x]
def get_init_inputs():
return []
```

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S1/ZZZJ_#130/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 channel_permute_torch import Model,get_inputs,get_init_inputs
from channel_permute_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()