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45_Average_Pooling_2Deven_workload_avg_pool2d_base

Level 1 • Task 45
import torch
import torch.nn as nn
import torch.nn.functional as F


def module_fn(
    x: torch.Tensor, kernel_size: int, stride: int, padding: int
) -> torch.Tensor:
    """
    Applies 2D Average Pooling using functional interface.

    Args:
        x (torch.Tensor): Input tensor
        kernel_size (int): Size of pooling window
        stride (int): Stride of pooling operation
        padding (int): Input padding

    Returns:
        torch.Tensor: Output tensor with 2D Average Pooling applied
    """
    return F.avg_pool2d(x, kernel_size=kernel_size, stride=stride, padding=padding)


class Model(nn.Module):
    """
    Simple model that performs 2D Average Pooling.
    """

    def __init__(self, kernel_size: int, stride: int, padding: int):
        """
        Initializes the Average Pooling layer.

        Args:
            kernel_size (int): Size of the pooling window
            stride (int): Stride of the pooling operation
            padding (int): Padding applied to input tensor
        """
        super(Model, self).__init__()
        self.kernel_size = kernel_size
        self.stride = stride
        self.padding = padding

    def forward(self, x: torch.Tensor, fn=module_fn) -> torch.Tensor:
        """
        Applies 2D Average Pooling to the input tensor.

        Args:
            x (torch.Tensor): Input tensor of shape (batch_size, channels, height, width)
            fn: Function to apply pooling operation, defaults to module_fn

        Returns:
            torch.Tensor: Output tensor with Average Pooling applied
        """
        return fn(
            x,
            self.kernel_size,
            self.stride,
            self.padding,
        )


batch_size = 16
channels = 64
height = 256
width = 256
kernel_size = 3
stride = None  # Defaults to kernel_size
padding = 0


def get_inputs():
    x = torch.randn(batch_size, channels, height, width)
    return [x]


def get_init_inputs():
    return [kernel_size, stride if stride is not None else kernel_size, padding]
import torch
import torch.nn as nn


class Model(nn.Module):
    """
    Simple model that performs 2D Average Pooling.
    """

    def __init__(self, kernel_size: int, stride: int = None, padding: int = 0):
        """
        Initializes the Average Pooling layer.

        Args:
            kernel_size (int): Size of the pooling window.
            stride (int, optional): Stride of the pooling operation. Defaults to None (same as kernel_size).
            padding (int, optional): Padding applied to the input tensor. Defaults to 0.
        """
        super(Model, self).__init__()
        self.avg_pool = nn.AvgPool2d(
            kernel_size=kernel_size, stride=stride, padding=padding
        )

    def forward(self, x: torch.Tensor) -> torch.Tensor:
        """
        Applies 2D Average Pooling to the input tensor.

        Args:
            x (torch.Tensor): Input tensor of shape (batch_size, channels, height, width).

        Returns:
            torch.Tensor: Output tensor with Average Pooling applied.
        """
        return self.avg_pool(x)


batch_size = 16
channels = 64
height = 256
width = 256
kernel_size = 3
stride = None  # Defaults to kernel_size
padding = 0


def get_inputs():
    x = torch.randn(batch_size, channels, height, width)
    return [x]


def get_init_inputs():
    return [kernel_size, stride if stride is not None else kernel_size, padding]

Kernel Information

Related Kernels (Level 1, Task 45 • 45_Average_Pooling_2D)

Rank Kernel Name Runtime (ms) Speedup Native Speedup Compile
🥇 unrolled_avg_pool2d_base 0.11 1.94 3.03
🥇 modular_avg_pool2d_base_base 0.11 1.94 3.03
🥇 grid_stride_manual_unroll_base 0.11 1.94 3.03
🥇 optimized_avg_pool2d_base 0.11 1.94 3.03
🥇 manual_unroll_avg_pool2d_base 0.11 1.94 3.03
🥇 efficient_avg_pool_base 0.11 1.94 3.03
🥇 constant_memory_avg_pool2d_base 0.11 1.94 3.03
🥇 even_workload_avg_pool2d_base 0.11 1.94 3.03
🥇 unrolled_optimized_avg_pool2d_base 0.11 1.94 3.03
10 warp_uniform_flow_base_base 0.11 1.83 2.87
10 optimized_avg_pool2d_base 0.11 1.83 2.87
10 grid_stride_avg_pool2d_base_base 0.11 1.83 2.87
10 warp_uniform_flow_base_edit_1 0.11 1.83 2.87
14 stride_optimized_avg_pool2d_base 0.12 1.82 2.84
14 warp_divergence_avg_pool2d_base 0.12 1.82 2.84
14 stride_loop_avg_pool2d_base 0.12 1.82 2.84
14 grid_unrolled_avg_pool2d_base 0.12 1.82 2.84
18 combined_avg_pool_base 0.12 1.80 2.82
18 spatial_block_optimized_base_base 0.12 1.80 2.82
18 spatial_block_optimized_base_edit_1 0.12 1.80 2.82
#include <torch/extension.h>
#include <cuda.h>
#include <cuda_runtime.h>

// Kernel that uses a flat 1D grid-stride loop to evenly distribute workload among threads

template <typename scalar_t>
__global__ void even_workload_avg_pool2d_kernel(
    const scalar_t* __restrict__ input,
    scalar_t* __restrict__ output,
    const int N,
    const int C,
    const int H,
    const int W,
    const int outH,
    const int outW,
    const int kernel_size,
    const int stride,
    const int padding
) {
    int total = N * C * outH * outW;
    int gridStride = blockDim.x * gridDim.x;
    
    // Each thread handles multiple output elements via grid-stride loop
    for (int idx = blockIdx.x * blockDim.x + threadIdx.x; idx < total; idx += gridStride) {
        // Compute the output coordinates
        int w_out = idx % outW;
        int h_out = (idx / outW) % outH;
        int c = (idx / (outW * outH)) % C;
        int n = idx / (outW * outH * C);
        
        // Calculate the corresponding top-left corner of the pooling window in input
        int in_x = w_out * stride - padding;
        int in_y = h_out * stride - padding;

        scalar_t sum = static_cast<scalar_t>(0);

        // Fast path for common 3x3 pooling when the entire window is within bounds
        if (kernel_size == 3 && in_x >= 0 && in_y >= 0 && (in_x + 3) <= W && (in_y + 3) <= H) {
            int base = (n * C + c) * H;
            int row0 = base + in_y;
            int row1 = row0 + 1;
            int row2 = row0 + 2;
            sum = input[row0 * W + in_x]     + input[row0 * W + in_x + 1]     + input[row0 * W + in_x + 2] +
                  input[row1 * W + in_x]     + input[row1 * W + in_x + 1]     + input[row1 * W + in_x + 2] +
                  input[row2 * W + in_x]     + input[row2 * W + in_x + 1]     + input[row2 * W + in_x + 2];
        } else {
            // Generic path: iterate over the pooling window with boundary checks
            for (int ky = 0; ky < kernel_size; ++ky) {
                int y = in_y + ky;
                if (y < 0 || y >= H) continue;
                int row_offset = ((n * C + c) * H + y) * W;
                for (int kx = 0; kx < kernel_size; ++kx) {
                    int x = in_x + kx;
                    if (x < 0 || x >= W) continue;
                    sum += input[row_offset + x];
                }
            }
        }

        output[idx] = sum / static_cast<scalar_t>(kernel_size * kernel_size);
    }
}

// Forward function exposed to PyTorch

torch::Tensor even_workload_avg_pool2d_forward(
    torch::Tensor x,
    int kernel_size,
    int stride,
    int padding
) {
    TORCH_CHECK(x.dim() == 4, "Input must be a 4D tensor.");
    
    int N = x.size(0);
    int C = x.size(1);
    int H = x.size(2);
    int W = x.size(3);
    
    // Compute output dimensions
    int outH = (H + 2 * padding - kernel_size) / stride + 1;
    int outW = (W + 2 * padding - kernel_size) / stride + 1;
    
    auto x_cont = x.contiguous();
    auto output = torch::empty({N, C, outH, outW}, x.options());
    
    int total = N * C * outH * outW;
    int threads = 256;
    int blocks = (total + threads - 1) / threads;
    
    AT_DISPATCH_FLOATING_TYPES(x.scalar_type(), "even_workload_avg_pool2d_kernel", ([&] {
        even_workload_avg_pool2d_kernel<scalar_t><<<blocks, threads>>>(
            x_cont.data_ptr<scalar_t>(),
            output.data_ptr<scalar_t>(),
            N, C, H, W,
            outH, outW,
            kernel_size, stride, padding
        );
    }));
    
    cudaError_t err = cudaGetLastError();
    TORCH_CHECK(err == cudaSuccess, "CUDA Error: ", cudaGetErrorString(err));
    
    return output;
}

PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
    m.def("forward", &even_workload_avg_pool2d_forward, "Evenly Distributed Average Pooling forward (CUDA)");
}
Performance Metrics
Metric Value Unit Variance Samples
Executed Ipc Active 2.326 inst/cycle 0.001 5
Executed Ipc Elapsed 2.242 inst/cycle 0.000 5
Issue Slots Busy 58.226 % 0.276 5
Issued Ipc Active 2.330 inst/cycle 0.001 5
SM Busy 58.226 % 0.276 5
Memory Throughput 3013507503756.941 byte/second 77590038585423069184.000 5
Mem Busy 51.214 % 0.025 5
Max Bandwidth 89.922 % 0.067 5
L1/TEX Hit Rate 65.720 % 0.000 5
L2 Hit Rate 13.082 % 0.001 5
Mem Pipes Busy 25.350 % 0.010 5
Warp Cycles Per Issued Instruction 23.396 cycle 0.022 5
Warp Cycles Per Executed Instruction 23.416 cycle 0.022 5
Avg. Active Threads Per Warp 32.000 0.000 5
Avg. Not Predicated Off Threads Per Warp 27.910 0.000 5
Max Active Clusters 0.000 cluster 0.000 5
Max Cluster Size 8.000 block 0.000 5
Overall GPU Occupancy 0.000 % 0.000 5
Cluster Occupancy 0.000 % 0.000 5
Block Limit SM 32.000 block 0.000 5
Block Limit Registers 8.000 block 0.000 5
Block Limit Shared Mem 32.000 block 0.000 5
Block Limit Warps 8.000 block 0.000 5
Theoretical Active Warps per SM 64.000 warp 0.000 5
Theoretical Occupancy 100.000 % 0.000 5
Achieved Occupancy 85.148 % 0.236 5
Achieved Active Warps Per SM 54.496 warp 0.098 5
Analysis Rules
Rule Description
INF HighPipeUtilization ALU is the highest-utilized pipeline (40.1%) based on active cycles, taking into account the rates of its different instructions. It executes integer and logic operations. It is well-utilized, but should not be a bottleneck.
INF CPIStall Check the Warp Stall Sampling (All Cycles) table for the top stall locations in your source based on sampling data. The Kernel Profiling Guide (https://docs.nvidia.com/nsight-compute/ProfilingGuide/index.html#metrics-reference) provides more details on each stall reason.
WRN Occupancy This kernel's theoretical occupancy is not impacted by any block limit. The difference between calculated theoretical (100.0%) and measured achieved occupancy (85.3%) can be the result of warp scheduling overheads or workload imbalances during the kernel execution. Load imbalances can occur between warps within a block as well as across blocks of the same kernel. See the CUDA Best Practices Guide (https://docs.nvidia.com/cuda/cuda-c-best-practices-guide/index.html#occupancy) for more details on optimizing occupancy.
Operation / Metric Value Unit
aten::randn
CPU Time 462421.17 μs
Device Time 0.00 μs
Self CPU Time 82.19 μs
Self Device Time 0.00 μs
CPU Memory Usage 0 B
Device Memory Usage 0 B
Self CPU Memory Usage 0 B
Self Device Memory Usage 0 B
aten::normal_
CPU Time 462312.42 μs
Device Time 0.00 μs
Self CPU Time 462312.42 μs
Self Device Time 0.00 μs
CPU Memory Usage 0 B
Device Memory Usage 0 B
Self CPU Memory Usage 0 B
Self Device Memory Usage 0 B
cudaLaunchKernel
CPU Time 1193136.55 μs
Device Time 57976.26 μs
Self CPU Time 1193136.55 μs
Self Device Time 57976.26 μs
CPU Memory Usage 0 B
Device Memory Usage 0 B
Self CPU Memory Usage 0 B
Self Device Memory Usage 0 B
void even_workload_avg_pool2d_kernel<float>(float const*, float*, int, int, int, int, int, int, int, int, int)
CPU Time 0.00 μs
Device Time 795567.41 μs
Self CPU Time 0.00 μs
Self Device Time 795567.41 μs
CPU Memory Usage 0 B
Device Memory Usage 0 B
Self CPU Memory Usage 0 B
Self Device Memory Usage 0 B
aten::zero_
CPU Time 727917.43 μs
Device Time 593398.61 μs
Self CPU Time 12712.13 μs
Self Device Time 0.00 μs
CPU Memory Usage 0 B
Device Memory Usage 0 B
Self CPU Memory Usage 0 B
Self Device Memory Usage 0 B
aten::fill_
CPU Time 715207.83 μs
Device Time 593398.61 μs
Self CPU Time 15996.88 μs
Self Device Time 593398.61 μs
CPU Memory Usage 0 B
Device Memory Usage 0 B
Self CPU Memory Usage 0 B
Self Device Memory Usage 0 B
void at::native::vectorized_elementwise_kernel<4, at::native::FillFunctor<int>, at::detail::Array<char*, 1> >(int, at::native::FillFunctor<int>, at::detail::Array<char*, 1>)
CPU Time 0.00 μs
Device Time 593398.61 μs
Self CPU Time 0.00 μs
Self Device Time 593398.61 μs
CPU Memory Usage 0 B
Device Memory Usage 0 B
Self CPU Memory Usage 0 B
Self Device Memory Usage 0 B
Status: Completed
45288 warnings generated when compiling for host.
Suppressed 45324 warnings (45277 in non-user code, 47 NOLINT).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
/home/robert_sakana_ai/llm_cuda/experiments/20250201_optimize_b10_s4_e0_sweep/level_1/task_45/b10_s2_even_workload_avg_pool2d/base/base.cu:14:5 bugprone-easily-swappable-parameters
14 | const int W,
| ^~~~~~~~~~~~
15 | const int outH,
| ~~~~~~~~~~~~~~
/home/robert_sakana_ai/llm_cuda/experiments/20250201_optimize_b10_s4_e0_sweep/level_1/task_45/b10_s2_even_workload_avg_pool2d/base/base.cu:14:15: note: the first parameter in the range is 'W'
14 | const int W,
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250201_optimize_b10_s4_e0_sweep/level_1/task_45/b10_s2_even_workload_avg_pool2d/base/base.cu:15:15: note: the last parameter in the range is 'outH'
15 | const int outH,
| ^~~~
/home/robert_sakana_ai/llm_cuda/experiments/20250201_optimize_b10_s4_e0_sweep/level_1/task_45/b10_s2_even_workload_avg_pool2d/base/base.cu:16:5: warning: 3 adjacent parameters of 'even_workload_avg_pool2d_kernel' of similar type ('const int') are easily swapped by mistake [bugprone-easily-swappable-parameters]
16 | const int outW,
| ^~~~~~~~~~~~~~~
17 | const int kernel_size,
| ~~~~~~~~~~~~~~~~~~~~~~
18 | const int stride,
| ~~~~~~~~~~~~~~~~
/home/robert_sakana_ai/llm_cuda/experiments/20250201_optimize_b10_s4_e0_sweep/level_1/task_45/b10_s2_even_workload_avg_pool2d/base/base.cu:16:15: note: the first parameter in the range is 'outW'
16 | const int outW,
| ^~~~
/home/robert_sakana_ai/llm_cuda/experiments/20250201_optimize_b10_s4_e0_sweep/level_1/task_45/b10_s2_even_workload_avg_pool2d/base/base.cu:18:15: note: the last parameter in the range is 'stride'
18 | const int stride,
| ^~~~~~
/home/robert_sakana_ai/llm_cuda/experiments/20250201_optimize_b10_s4_e0_sweep/level_1/task_45/b10_s2_even_workload_avg_pool2d/base/base.cu:22:22: warning: narrowing conversion from 'unsigned int' to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
22 | int gridStride = blockDim.x * gridDim.x;
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250201_optimize_b10_s4_e0_sweep/level_1/task_45/b10_s2_even_workload_avg_pool2d/base/base.cu:25:20: warning: narrowing conversion from 'unsigned int' to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
25 | for (int idx = blockIdx.x * blockDim.x + threadIdx.x; idx < total; idx += gridStride) {
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250201_optimize_b10_s4_e0_sweep/level_1/task_45/b10_s2_even_workload_avg_pool2d/base/base.cu:75:13: warning: narrowing conversion from 'int64_t' (aka 'long') to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
75 | int N = x.size(0);
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250201_optimize_b10_s4_e0_sweep/level_1/task_45/b10_s2_even_workload_avg_pool2d/base/base.cu:76:13: warning: narrowing conversion from 'int64_t' (aka 'long') to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
76 | int C = x.size(1);
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250201_optimize_b10_s4_e0_sweep/level_1/task_45/b10_s2_even_workload_avg_pool2d/base/base.cu:77:13: warning: narrowing conversion from 'int64_t' (aka 'long') to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
77 | int H = x.size(2);
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250201_optimize_b10_s4_e0_sweep/level_1/task_45/b10_s2_even_workload_avg_pool2d/base/base.cu:78:13: warning: narrowing conversion from 'int64_t' (aka 'long') to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
78 | int W = x.size(3);
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250201_optimize_b10_s4_e0_sweep/level_1/task_45/b10_s2_even_workload_avg_pool2d/base/base.cu:91:5: warning: inside a lambda, '__func__' expands to the name of the function call operator; consider capturing the name of the enclosing function explicitly [bugprone-lambda-function-name]
91 | AT_DISPATCH_FLOATING_TYPES(x.scalar_type(), "even_workload_avg_pool2d_kernel", ([&] {
| ^
/home/robert_sakana_ai/miniconda3/envs/llm2cuda/lib/python3.11/site-packages/torch/include/ATen/Dispatch.h:237:34: note: expanded from macro 'AT_DISPATCH_FLOATING_TYPES'
237 | AT_DISPATCH_SWITCH(TYPE, NAME, AT_DISPATCH_CASE_FLOATING_TYPES(__VA_ARGS__))
| ^
/home/robert_sakana_ai/miniconda3/envs/llm2cuda/lib/python3.11/site-packages/torch/include/ATen/Dispatch.h:233:3: note: expanded from macro 'AT_DISPATCH_CASE_FLOATING_TYPES'
233 | AT_DISPATCH_CASE(at::ScalarType::Double, __VA_ARGS__) \
| ^
/home/robert_sakana_ai/miniconda3/envs/llm2cuda/lib/python3.11/site-packages/torch/include/ATen/Dispatch.h:74:3: note: expanded from macro 'AT_DISPATCH_CASE'
74 | AT_PRIVATE_CASE_TYPE_USING_HINT(enum_type, scalar_t, __VA_ARGS__)
| ^
note: (skipping 1 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
/home/robert_sakana_ai/miniconda3/envs/llm2cuda/lib/python3.11/site-packages/torch/include/ATen/Dispatch.h:58:7: note: expanded from macro 'AT_PRIVATE_CHECK_SELECTIVE_BUILD'
58 | AT_ERROR( \
| ^
/home/robert_sakana_ai/miniconda3/envs/llm2cuda/lib/python3.11/site-packages/torch/include/c10/util/Exception.h:711:32: note: expanded from macro 'AT_ERROR'
711 | C10_EXPAND_MSVC_WORKAROUND(TORCH_CHECK(false, ::c10::str(__VA_ARGS__))); \
| ^
/home/robert_sakana_ai/miniconda3/envs/llm2cuda/lib/python3.11/site-packages/torch/include/c10/util/Exception.h:536:9: note: expanded from macro 'TORCH_CHECK'
536 | __func__, \
| ^