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41_Max_Pooling_1Dcoalesced_aligned_pooling_base

Level 1 • Task 41
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,
    dilation: int,
    return_indices: bool,
) -> torch.Tensor:
    """
    Functional implementation of Max Pooling 1D.

    Args:
        x (torch.Tensor): Input tensor of shape (batch_size, num_features, sequence_length).
        kernel_size (int): Size of the window to take a max over.
        stride (int): Stride of the window.
        padding (int): Implicit zero padding to be added on both sides.
        dilation (int): Spacing between kernel elements.
        return_indices (bool): Whether to return the indices of the maximum values.

    Returns:
        torch.Tensor: Output tensor with Max Pooling 1D applied.
    """
    return F.max_pool1d(
        x,
        kernel_size=kernel_size,
        stride=stride,
        padding=padding,
        dilation=dilation,
        return_indices=return_indices,
    )


class Model(nn.Module):
    """
    Simple model that performs Max Pooling 1D.
    """

    def __init__(
        self,
        kernel_size: int,
        stride: int,
        padding: int,
        dilation: int,
        return_indices: bool,
    ):
        """
        Initializes the Max Pooling 1D layer.

        Args:
            kernel_size (int): Size of the window to take a max over.
            stride (int): Stride of the window.
            padding (int): Implicit zero padding to be added on both sides.
            dilation (int): Spacing between kernel elements.
            return_indices (bool): Whether to return the indices of the maximum values.
        """
        super(Model, self).__init__()
        self.kernel_size = kernel_size
        self.stride = stride
        self.padding = padding
        self.dilation = dilation
        self.return_indices = return_indices

    def forward(self, x: torch.Tensor, fn=module_fn) -> torch.Tensor:
        """
        Applies Max Pooling 1D to the input tensor.

        Args:
            x (torch.Tensor): Input tensor of shape (batch_size, num_features, sequence_length).
            fn: Function to apply (defaults to module_fn)

        Returns:
            torch.Tensor: Output tensor with Max Pooling 1D applied.
        """
        return fn(
            x,
            self.kernel_size,
            self.stride,
            self.padding,
            self.dilation,
            self.return_indices,
        )


batch_size = 16
features = 64
sequence_length = 128
kernel_size = 4
stride = 2
padding = 2
dilation = 3
return_indices = False


def get_inputs():
    x = torch.randn(batch_size, features, sequence_length)
    return [x]


def get_init_inputs():
    return [kernel_size, stride, padding, dilation, return_indices]
import torch
import torch.nn as nn

class Model(nn.Module):
    """
    Simple model that performs Max Pooling 1D.
    """
    def __init__(self, kernel_size: int, stride: int = None, padding: int = 0, dilation: int = 1, return_indices: bool = False):
        """
        Initializes the Max Pooling 1D layer.

        Args:
            kernel_size (int): Size of the window to take a max over.
            stride (int, optional): Stride of the window. Defaults to None (same as kernel_size).
            padding (int, optional): Implicit zero padding to be added on both sides. Defaults to 0.
            dilation (int, optional): Spacing between kernel elements. Defaults to 1.
            return_indices (bool, optional): Whether to return the indices of the maximum values. Defaults to False.
        """
        super(Model, self).__init__()
        self.maxpool = nn.MaxPool1d(kernel_size=kernel_size, stride=stride, padding=padding, dilation=dilation, return_indices=return_indices)

    def forward(self, x: torch.Tensor) -> torch.Tensor:
        """
        Applies Max Pooling 1D to the input tensor.

        Args:
            x (torch.Tensor): Input tensor of shape (batch_size, num_features, sequence_length).

        Returns:
            torch.Tensor: Output tensor with Max Pooling 1D applied, shape (batch_size, num_features, output_sequence_length).
        """
        return self.maxpool(x)

batch_size = 16
features = 64
sequence_length = 128
kernel_size = 4
stride = 2
padding = 2
dilation = 3
return_indices = False

def get_inputs():
    x = torch.randn(batch_size, features, sequence_length)
    return [x]

def get_init_inputs():
    return [kernel_size, stride, padding, dilation, return_indices]

Kernel Information

Related Kernels (Level 1, Task 41 • 41_Max_Pooling_1D)

Rank Kernel Name Runtime (ms) Speedup Native Speedup Compile
🥇 41_Max_Pooling_1D 0.01 1.18 5.01
🥇 max_pool1d_shared_opt_base 0.01 1.18 5.01
🥇 optimized_workload_distributed_pool1d_base 0.01 1.18 5.01
🥇 max_pool1d_optimized_grid_base 0.01 1.18 5.01
🥇 optimized_max_pool1d_kernel_base 0.01 1.18 5.01
🥇 max_pool1d_kernel_combined_base 0.01 1.18 5.01
🥇 max_pool1d_nosync_base 0.01 1.18 5.01
🥇 coalesced_writes_edit_1 0.01 1.18 5.01
🥇 aligned_memory_access_base 0.01 1.18 5.01
🥇 aligned_memory_access_edit_1 0.01 1.18 5.01
🥇 loop_unrolling_base 0.01 1.18 5.01
🥇 balanced_workload_distribution_base 0.01 1.18 5.01
🥇 balanced_max_pool1d_base 0.01 1.18 5.01
🥇 balanced_workload_distribution_edit_1 0.01 1.18 5.01
🥇 max_pool1d_fused_kernel_base 0.01 1.18 5.01
🥇 coalesced_max_pool1d_kernel_base_base 0.01 1.18 5.01
🥇 experimental_block_size_pool1d_base_base 0.01 1.18 5.01
🥇 max_pool1d_tunable_base 0.01 1.18 5.01
🥇 coalesced_aligned_pooling_base 0.01 1.18 5.01
🥇 modular_device_functions_edit_1_base 0.01 1.18 5.01
#include <torch/extension.h>
#include <cuda.h>
#include <cuda_runtime.h>

// This kernel organizes threads so that each block processes contiguous output indices along the innermost dimension.
// Threads in the same warp will access consecutive memory locations in the output tensor, ensuring memory coalescing.

__global__ void max_pool1d_coalesced_aligned_kernel(
    const float* __restrict__ input,
    float* __restrict__ output,
    int64_t* __restrict__ indices,
    const int batch_size,
    const int num_channels,
    const int input_length,
    const int kernel_size,
    const int stride,
    const int padding,
    const int dilation,
    const int output_length,
    const bool return_indices) {

    // Use a 2D grid: blockIdx.x covers output index dimension; blockIdx.y covers (b, c) combinations.
    int i = blockIdx.x * blockDim.x + threadIdx.x;  // output index in the innermost dimension
    int row = blockIdx.y;  // Flattened index for (batch, channel)
    int b = row / num_channels;
    int c = row % num_channels;

    if (i >= output_length) return;

    // Compute base pointer for the current batch and channel
    const float* input_base = input + (b * num_channels * input_length + c * input_length);
    int input_start = i * stride - padding;

    float max_val = -INFINITY;
    int max_idx = -1;

    // Loop over the pooling window
    for (int k = 0; k < kernel_size; ++k) {
        int pos = input_start + k * dilation;
        if (pos >= 0 && pos < input_length) {
            float val = __ldg(input_base + pos);
            if (val > max_val) {
                max_val = val;
                max_idx = pos;
            }
        }
    }

    // Compute the output index. Memory layout: [b, c, i] with i as the fastest dimension.
    int out_index = b * (num_channels * output_length) + c * output_length + i;
    output[out_index] = max_val;
    if (return_indices)
        indices[out_index] = max_idx;
}


// The forward function creates output tensors and launches the kernel with a 2D grid.
// Grid dimensions:
//   - gridDim.x: covers the output_length dimension using blockDim.x threads
//   - gridDim.y: covers the (batch, channel) combinations

torch::Tensor forward(
    torch::Tensor x,
    int64_t kernel_size,
    int64_t stride,
    int64_t padding,
    int64_t dilation,
    bool return_indices) {

    TORCH_CHECK(x.dim() == 3, "Input must be a 3D tensor.");
    TORCH_CHECK(x.is_cuda(), "Input tensor must be on CUDA.");
    TORCH_CHECK(x.is_contiguous(), "Input tensor must be contiguous.");

    const int batch_size = x.size(0);
    const int num_channels = x.size(1);
    const int input_length = x.size(2);

    const int output_length = ((input_length + 2 * padding - dilation * (kernel_size - 1) - 1) / stride) + 1;
    TORCH_CHECK(output_length > 0, "Output length must be positive.");

    auto options = torch::TensorOptions().dtype(x.dtype()).device(x.device());
    auto output = torch::empty({batch_size, num_channels, output_length}, options);
    torch::Tensor indices;
    if (return_indices) {
        indices = torch::empty({batch_size, num_channels, output_length}, options.dtype(torch::kInt64));
    }

    // Configure a 2D grid: threads.x covers the contiguous 'i' dimension, threads in each block read/write consecutive
    // memory locations, ensuring coalescing. Block dimension in y is implicitly 1.
    const int threads_x = 256;
    dim3 threads(threads_x);
    dim3 blocks((output_length + threads_x - 1) / threads_x, batch_size * num_channels);

    max_pool1d_coalesced_aligned_kernel<<<blocks, threads>>>(
        x.data_ptr<float>(),
        output.data_ptr<float>(),
        return_indices ? indices.data_ptr<int64_t>() : nullptr,
        batch_size,
        num_channels,
        input_length,
        kernel_size,
        stride,
        padding,
        dilation,
        output_length,
        return_indices
    );

    return return_indices ? torch::cat({output, indices}, -1) : output;
}

PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
    m.def("forward", &forward, "MaxPool1D forward with coalesced and aligned accesses (CUDA)");
}
Performance Metrics
Metric Value Unit Variance Samples
Executed Ipc Active 0.770 inst/cycle 0.000 5
Executed Ipc Elapsed 0.298 inst/cycle 0.000 5
Issue Slots Busy 21.702 % 0.039 5
Issued Ipc Active 0.868 inst/cycle 0.000 5
SM Busy 21.702 % 0.039 5
Memory Throughput 134136553042.824 byte/second 4306120113096010240.000 5
Mem Busy 10.384 % 0.038 5
Max Bandwidth 7.198 % 0.012 5
L1/TEX Hit Rate 69.170 % 0.001 5
L2 Hit Rate 71.638 % 0.068 5
Mem Pipes Busy 10.254 % 0.027 5
Warp Cycles Per Issued Instruction 37.308 cycle 14.840 5
Warp Cycles Per Executed Instruction 42.112 cycle 18.926 5
Avg. Active Threads Per Warp 31.270 0.000 5
Avg. Not Predicated Off Threads Per Warp 30.140 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 48.730 % 0.297 5
Achieved Active Warps Per SM 31.186 warp 0.123 5
Analysis Rules
Rule Description
WRN HighPipeUtilization All compute pipelines are under-utilized. Either this kernel is very small or it doesn't issue enough warps per scheduler. Check the Launch Statistics and Scheduler Statistics sections for further details.
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 (48.4%) 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::to
CPU Time 586641.18 μs
Device Time 21.15 μs
Self CPU Time 37.47 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::_to_copy
CPU Time 586603.70 μs
Device Time 21.15 μs
Self CPU Time 92.55 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::empty_strided
CPU Time 586355.53 μs
Device Time 0.00 μs
Self CPU Time 80.65 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
cudaDeviceGetStreamPriorityRange
CPU Time 586094.70 μs
Device Time 0.00 μs
Self CPU Time 586094.70 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 496763.53 μs
Device Time 23209.08 μs
Self CPU Time 496763.53 μs
Self Device Time 23209.08 μs
CPU Memory Usage 0 B
Device Memory Usage 0 B
Self CPU Memory Usage 0 B
Self Device Memory Usage 0 B
max_pool1d_coalesced_aligned_kernel(float const*, float*, long*, int, int, int, int, int, int, int, int, bool)
CPU Time 0.00 μs
Device Time 23489.02 μs
Self CPU Time 0.00 μs
Self Device Time 23489.02 μs
CPU Memory Usage 0 B
Device Memory Usage 0 B
Self CPU Memory Usage 0 B
Self Device Memory Usage 0 B
cudaEventRecord
CPU Time 19972.54 μs
Device Time 42935.22 μs
Self CPU Time 19972.54 μs
Self Device Time 42935.22 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 64403.92 μs
Device Time 641017.91 μs
Self CPU Time 14782.79 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 49625.36 μs
Device Time 641017.91 μs
Self CPU Time 15775.05 μs
Self Device Time 641017.91 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 641017.91 μs
Self CPU Time 0.00 μs
Self Device Time 641017.91 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
45293 warnings generated when compiling for host.
Suppressed 45326 warnings (45279 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/20250211_optimize_b5_s4_e1_v2/level_1/task_41/b4_s3_coalesced_aligned_pooling/base/base.cu:12:5 bugprone-easily-swappable-parameters
12 | const int batch_size,
| ^~~~~~~~~~~~~~~~~~~~~
13 | const int num_channels,
| ~~~~~~~~~~~~~~~~~~~~~~
/home/robert_sakana_ai/llm_cuda/experiments/20250211_optimize_b5_s4_e1_v2/level_1/task_41/b4_s3_coalesced_aligned_pooling/base/base.cu:12:15: note: the first parameter in the range is 'batch_size'
12 | const int batch_size,
| ^~~~~~~~~~
/home/robert_sakana_ai/llm_cuda/experiments/20250211_optimize_b5_s4_e1_v2/level_1/task_41/b4_s3_coalesced_aligned_pooling/base/base.cu:13:15: note: the last parameter in the range is 'num_channels'
13 | const int num_channels,
| ^~~~~~~~~~~~
/home/robert_sakana_ai/llm_cuda/experiments/20250211_optimize_b5_s4_e1_v2/level_1/task_41/b4_s3_coalesced_aligned_pooling/base/base.cu:14:5: warning: 3 adjacent parameters of 'max_pool1d_coalesced_aligned_kernel' of similar type ('const int') are easily swapped by mistake [bugprone-easily-swappable-parameters]
14 | const int input_length,
| ^~~~~~~~~~~~~~~~~~~~~~~
15 | const int kernel_size,
| ~~~~~~~~~~~~~~~~~~~~~~
16 | const int stride,
| ~~~~~~~~~~~~~~~~
/home/robert_sakana_ai/llm_cuda/experiments/20250211_optimize_b5_s4_e1_v2/level_1/task_41/b4_s3_coalesced_aligned_pooling/base/base.cu:14:15: note: the first parameter in the range is 'input_length'
14 | const int input_length,
| ^~~~~~~~~~~~
/home/robert_sakana_ai/llm_cuda/experiments/20250211_optimize_b5_s4_e1_v2/level_1/task_41/b4_s3_coalesced_aligned_pooling/base/base.cu:16:15: note: the last parameter in the range is 'stride'
16 | const int stride,
| ^~~~~~
/home/robert_sakana_ai/llm_cuda/experiments/20250211_optimize_b5_s4_e1_v2/level_1/task_41/b4_s3_coalesced_aligned_pooling/base/base.cu:17:5: warning: 3 adjacent parameters of 'max_pool1d_coalesced_aligned_kernel' of similar type ('const int') are easily swapped by mistake [bugprone-easily-swappable-parameters]
17 | const int padding,
| ^~~~~~~~~~~~~~~~~~
18 | const int dilation,
| ~~~~~~~~~~~~~~~~~~~
19 | const int output_length,
| ~~~~~~~~~~~~~~~~~~~~~~~
/home/robert_sakana_ai/llm_cuda/experiments/20250211_optimize_b5_s4_e1_v2/level_1/task_41/b4_s3_coalesced_aligned_pooling/base/base.cu:17:15: note: the first parameter in the range is 'padding'
17 | const int padding,
| ^~~~~~~
/home/robert_sakana_ai/llm_cuda/experiments/20250211_optimize_b5_s4_e1_v2/level_1/task_41/b4_s3_coalesced_aligned_pooling/base/base.cu:19:15: note: the last parameter in the range is 'output_length'
19 | const int output_length,
| ^~~~~~~~~~~~~
/home/robert_sakana_ai/llm_cuda/experiments/20250211_optimize_b5_s4_e1_v2/level_1/task_41/b4_s3_coalesced_aligned_pooling/base/base.cu:23:13: warning: narrowing conversion from 'unsigned int' to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
23 | int i = blockIdx.x * blockDim.x + threadIdx.x; // output index in the innermost dimension
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250211_optimize_b5_s4_e1_v2/level_1/task_41/b4_s3_coalesced_aligned_pooling/base/base.cu:24:15: warning: narrowing conversion from 'unsigned int' to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
24 | int row = blockIdx.y; // Flattened index for (batch, channel)
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250211_optimize_b5_s4_e1_v2/level_1/task_41/b4_s3_coalesced_aligned_pooling/base/base.cu:63:19: warning: the parameter 'x' is copied for each invocation but only used as a const reference; consider making it a const reference [performance-unnecessary-value-param]
63 | torch::Tensor x,
| ^
| const &
/home/robert_sakana_ai/llm_cuda/experiments/20250211_optimize_b5_s4_e1_v2/level_1/task_41/b4_s3_coalesced_aligned_pooling/base/base.cu:74:28: warning: narrowing conversion from 'int64_t' (aka 'long') to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
74 | const int batch_size = x.size(0);
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250211_optimize_b5_s4_e1_v2/level_1/task_41/b4_s3_coalesced_aligned_pooling/base/base.cu:75:30: warning: narrowing conversion from 'int64_t' (aka 'long') to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
75 | const int num_channels = x.size(1);
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250211_optimize_b5_s4_e1_v2/level_1/task_41/b4_s3_coalesced_aligned_pooling/base/base.cu:76:30: warning: narrowing conversion from 'int64_t' (aka 'long') to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
76 | const int input_length = x.size(2);
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250211_optimize_b5_s4_e1_v2/level_1/task_41/b4_s3_coalesced_aligned_pooling/base/base.cu:78:31: warning: narrowing conversion from 'int64_t' (aka 'long') to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
78 | const int output_length = ((input_length + 2 * padding - dilation * (kernel_size - 1) - 1) / stride) + 1;
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250211_optimize_b5_s4_e1_v2/level_1/task_41/b4_s3_coalesced_aligned_pooling/base/base.cu:101:9: warning: narrowing conversion from 'int64_t' (aka 'long') to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
101 | kernel_size,
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250211_optimize_b5_s4_e1_v2/level_1/task_41/b4_s3_coalesced_aligned_pooling/base/base.cu:102:9: warning: narrowing conversion from 'int64_t' (aka 'long') to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
102 | stride,
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250211_optimize_b5_s4_e1_v2/level_1/task_41/b4_s3_coalesced_aligned_pooling/base/base.cu:103:9: warning: narrowing conversion from 'int64_t' (aka 'long') to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
103 | padding,
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250211_optimize_b5_s4_e1_v2/level_1/task_41/b4_s3_coalesced_aligned_pooling/base/base.cu:104:9: warning: narrowing conversion from 'int64_t' (aka 'long') to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
104 | dilation,
| ^