GPUCodeForces/S1/uucoco_#8/ChannelShuffle_cuda.py

121 lines
3.4 KiB
Python

import torch
import torch.nn as nn
from torch.utils.cpp_extension import load_inline
N, C, H, W = 32, 64, 56, 56
GROUPS = 4
assert (H * W) % 4 == 0, "Spatial size (H*W) must be a multiple of 4"
class ModelNew(nn.Module):
def __init__(self, groups=GROUPS):
super().__init__()
self.groups = groups
self.block_size = 256
self._compile_cuda_kernel()
def _compile_cuda_kernel(self):
cpp_source = """
#include <torch/extension.h>
torch::Tensor channel_shuffle_cuda(torch::Tensor input, int groups);
"""
cuda_source = f"""
#include <cuda_runtime.h>
#define BLOCK_SIZE {self.block_size}
__global__ void channel_shuffle_kernel(
const float* __restrict__ input,
float* __restrict__ output,
int N,
int C,
int S_vec, // H * W / 4
int groups,
int channels_per_group
) {{
int total_threads = N * C * S_vec;
int idx = blockIdx.x * blockDim.x + threadIdx.x;
for (; idx < total_threads; idx += gridDim.x * blockDim.x) {{
int s = idx % S_vec;
int tmp = idx / S_vec;
int c_in = tmp % C;
int n = tmp / C;
int g_idx = c_in / channels_per_group;
int c_idx = c_in % channels_per_group;
int c_out = c_idx * groups + g_idx;
int out_global_idx = (n * C + c_out) * S_vec + s;
const float4* in_ptr = reinterpret_cast<const float4*>(input);
float4* out_ptr = reinterpret_cast<float4*>(output);
out_ptr[out_global_idx] = in_ptr[idx];
}}
}}
torch::Tensor channel_shuffle_cuda(torch::Tensor input, int groups) {{
TORCH_CHECK(input.is_cuda(), "Input must be a CUDA tensor");
TORCH_CHECK(input.dim() == 4, "Input must be 4D (N, C, H, W)");
int N = input.size(0);
int C = input.size(1);
int H = input.size(2);
int W = input.size(3);
TORCH_CHECK(C % groups == 0, "Channels must be divisible by groups");
TORCH_CHECK((H * W) % 4 == 0, "Spatial size must be divisible by 4 for float4 optimization");
input = input.contiguous();
auto output = torch::empty_like(input);
int S = H * W;
int S_vec = S / 4;
int channels_per_group = C / groups;
int total_threads = N * C * S_vec;
int blocks = std::min((total_threads + BLOCK_SIZE - 1) / BLOCK_SIZE, 1024);
channel_shuffle_kernel<<<blocks, BLOCK_SIZE>>>(
input.data_ptr<float>(),
output.data_ptr<float>(),
N,
C,
S_vec,
groups,
channels_per_group
);
return output;
}}
"""
self.op = load_inline(
name='channel_shuffle_cuda_opt_v1',
cpp_sources=cpp_source,
cuda_sources=cuda_source,
functions=['channel_shuffle_cuda'],
extra_cuda_cflags=['-O3'],
verbose=False
)
def forward(self, x: torch.Tensor) -> torch.Tensor:
if not x.is_cuda: x = x.cuda()
return self.op.channel_shuffle_cuda(x, self.groups)