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31_ELU31_elu_optimized_indexing_base

Level 1 • Task 31
import torch
import torch.nn as nn
import torch.nn.functional as F


def module_fn(x: torch.Tensor, alpha: float) -> torch.Tensor:
    """
    Applies ELU activation to the input tensor.

    Args:
        x (torch.Tensor): Input tensor of any shape.
        alpha (float): The alpha parameter for the ELU function.

    Returns:
        torch.Tensor: Output tensor with ELU applied, same shape as input.
    """
    return F.elu(x, alpha=alpha)


class Model(nn.Module):
    """
    Simple model that performs an ELU activation.
    """

    def __init__(self, alpha):
        """
        Initializes the ELU model.

        Args:
            alpha (float): The alpha parameter for the ELU function.
        """
        super(Model, self).__init__()
        self.alpha = alpha

    def forward(self, x: torch.Tensor, fn=module_fn) -> torch.Tensor:
        """
        Applies ELU activation to the input tensor.

        Args:
            x (torch.Tensor): Input tensor of any shape.

        Returns:
            torch.Tensor: Output tensor with ELU applied, same shape as input.
        """
        return fn(x, self.alpha)


batch_size = 16
dim = 16384
alpha = 1.0


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


def get_init_inputs():
    return [alpha]
import torch
import torch.nn as nn
import torch.nn.functional as F

class Model(nn.Module):
    """
    Simple model that performs an ELU activation.
    """
    def __init__(self, alpha: float = 1.0):
        """
        Initializes the ELU model.

        Args:
            alpha (float, optional): The alpha parameter for the ELU function. Defaults to 1.0.
        """
        super(Model, self).__init__()
        self.alpha = alpha
    
    def forward(self, x: torch.Tensor) -> torch.Tensor:
        """
        Applies ELU activation to the input tensor.

        Args:
            x (torch.Tensor): Input tensor of any shape.

        Returns:
            torch.Tensor: Output tensor with ELU applied, same shape as input.
        """
        return F.elu(x, alpha=self.alpha)

batch_size = 16
dim = 16384

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

def get_init_inputs():
    return [1.0]  # Provide alpha value for initialization

Kernel Information

Related Kernels (Level 1, Task 31 • 31_ELU)

Rank Kernel Name Runtime (ms) Speedup Native Speedup Compile
🥇 31_elu_shared_base 0.01 1.14 4.80
🥇 hybrid_elu_optimized_base 0.01 1.14 4.80
🥇 31_elu_vectorized_base 0.01 1.14 4.80
🥇 vec_shared_elu_base 0.01 1.14 4.80
🥇 31_elu_grid_stride_base_base 0.01 1.14 4.80
🥇 31_elu_vectorized_edit_1 0.01 1.14 4.80
🥇 elu_unroll_kernel_base 0.01 1.14 4.80
🥇 ldg_elu_128_base 0.01 1.14 4.80
9 31_ELU 0.01 0.97 4.12
9 31_elu_aligned_coalesced_base 0.01 0.97 4.12
9 hybrid_elu_base 0.01 0.97 4.12
9 31_elu_optimized_indexing_base 0.01 0.97 4.12
9 31_elu_reduced_divergence_base 0.01 0.97 4.12
9 elu_hybrid_base 0.01 0.97 4.12
9 31_elu_coalesced_base 0.01 0.97 4.12
9 31_elu_shared_mem_base 0.01 0.97 4.12
9 modular_elu_base 0.01 0.97 4.12
9 elu_vec4_shared_base 0.01 0.97 4.12
9 elu_tuned_blocksize_base 0.01 0.97 4.12
9 branchless_elu_vectorized_base 0.01 0.97 4.12
#include <torch/extension.h>
#include <cuda.h>
#include <cuda_runtime.h>
#include <math.h>

#define CHECK_CUDA(x) TORCH_CHECK(x.is_cuda(), #x " must be a CUDA tensor")
#define CHECK_CONTIGUOUS(x) TORCH_CHECK(x.is_contiguous(), #x " must be contiguous")
#define CHECK_INPUT(x) CHECK_CUDA(x); CHECK_CONTIGUOUS(x)

__global__ void elu_kernel_optimized(const float* x, float* out, float alpha, int n) {
    int idx = blockIdx.x * blockDim.x + threadIdx.x;
    int stride = blockDim.x * gridDim.x;
    
    for (int i = idx; i < n; i += stride) {
        float val = x[i];
        out[i] = (val > 0) ? val : alpha * (expf(val) - 1);
    }
}

torch::Tensor elu_cuda(torch::Tensor x, float alpha) {
    CHECK_INPUT(x);
    auto out = torch::empty_like(x);
    int n = x.numel();
    
    const int threads = 256;
    const int blocks = (n + threads - 1) / threads;
    
    elu_kernel_optimized<<<blocks, threads>>>(x.data_ptr<float>(), out.data_ptr<float>(), alpha, n);
    
    return out;
}

PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
    m.def("forward", &elu_cuda, "ELU activation with optimized indexing (CUDA)");
}
Performance Metrics
Metric Value Unit Variance Samples
Executed Ipc Active 1.334 inst/cycle 0.000 5
Executed Ipc Elapsed 0.584 inst/cycle 0.000 5
Issue Slots Busy 35.786 % 0.015 5
Issued Ipc Active 1.432 inst/cycle 0.000 5
SM Busy 35.786 % 0.015 5
Memory Throughput 261105837744.474 byte/second 6953858628345210880.000 5
Mem Busy 12.354 % 0.007 5
Max Bandwidth 11.522 % 0.011 5
L1/TEX Hit Rate 0.000 % 0.000 5
L2 Hit Rate 66.068 % 0.234 5
Mem Pipes Busy 14.894 % 0.021 5
Warp Cycles Per Issued Instruction 34.398 cycle 0.018 5
Warp Cycles Per Executed Instruction 36.902 cycle 0.020 5
Avg. Active Threads Per Warp 32.000 0.000 5
Avg. Not Predicated Off Threads Per Warp 26.930 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 10.000 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 77.680 % 0.064 5
Achieved Active Warps Per SM 49.718 warp 0.027 5
Analysis Rules
Rule Description
INF HighPipeUtilization ALU is the highest-utilized pipeline (23.3%) 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.
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 (77.3%) 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.
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.
Operation / Metric Value Unit
aten::to
CPU Time 487928.99 μs
Device Time 40.19 μs
Self CPU Time 35.14 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 487893.85 μs
Device Time 40.19 μs
Self CPU Time 82.31 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 507864.36 μs
Device Time 0.00 μs
Self CPU Time 20398.45 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 484357.07 μs
Device Time 0.00 μs
Self CPU Time 484357.07 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 508532.19 μs
Device Time 22905.53 μs
Self CPU Time 508532.19 μs
Self Device Time 22905.53 μs
CPU Memory Usage 0 B
Device Memory Usage 0 B
Self CPU Memory Usage 0 B
Self Device Memory Usage 0 B
elu_kernel_optimized(float const*, float*, float, int)
CPU Time 0.00 μs
Device Time 35131.54 μs
Self CPU Time 0.00 μs
Self Device Time 35131.54 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 21070.56 μs
Device Time 44192.13 μs
Self CPU Time 21070.56 μs
Self Device Time 44192.13 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 73872.55 μs
Device Time 654442.06 μs
Self CPU Time 14893.23 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 58983.88 μs
Device Time 654442.06 μs
Self CPU Time 16462.31 μs
Self Device Time 654442.06 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 654442.06 μs
Self CPU Time 0.00 μs
Self Device Time 654442.06 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
45282 warnings generated when compiling for host.
Suppressed 45322 warnings (45275 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/20250202_optimize_b10_s4_e0_sweep/level_1/task_31/b3_s2_31_elu_optimized_indexing/base/base.cu:6:35 bugprone-macro-parentheses
6 | #define CHECK_CUDA(x) TORCH_CHECK(x.is_cuda(), #x " must be a CUDA tensor")
| ^
| ()
/home/robert_sakana_ai/llm_cuda/experiments/20250202_optimize_b10_s4_e0_sweep/level_1/task_31/b3_s2_31_elu_optimized_indexing/base/base.cu:7:41: warning: macro argument should be enclosed in parentheses [bugprone-macro-parentheses]
7 | #define CHECK_CONTIGUOUS(x) TORCH_CHECK(x.is_contiguous(), #x " must be contiguous")
| ^
| ()
/home/robert_sakana_ai/llm_cuda/experiments/20250202_optimize_b10_s4_e0_sweep/level_1/task_31/b3_s2_31_elu_optimized_indexing/base/base.cu:10:66: warning: 2 adjacent parameters of 'elu_kernel_optimized' of convertible types are easily swapped by mistake [bugprone-easily-swappable-parameters]
10 | __global__ void elu_kernel_optimized(const float* x, float* out, float alpha, int n) {
| ^~~~~~~~~~~~~~~~~~
/home/robert_sakana_ai/llm_cuda/experiments/20250202_optimize_b10_s4_e0_sweep/level_1/task_31/b3_s2_31_elu_optimized_indexing/base/base.cu:10:72: note: the first parameter in the range is 'alpha'
10 | __global__ void elu_kernel_optimized(const float* x, float* out, float alpha, int n) {
| ^~~~~
/home/robert_sakana_ai/llm_cuda/experiments/20250202_optimize_b10_s4_e0_sweep/level_1/task_31/b3_s2_31_elu_optimized_indexing/base/base.cu:10:83: note: the last parameter in the range is 'n'
10 | __global__ void elu_kernel_optimized(const float* x, float* out, float alpha, int n) {
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250202_optimize_b10_s4_e0_sweep/level_1/task_31/b3_s2_31_elu_optimized_indexing/base/base.cu:10:79: note: 'float' and 'int' may be implicitly converted
10 | __global__ void elu_kernel_optimized(const float* x, float* out, float alpha, int n) {
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250202_optimize_b10_s4_e0_sweep/level_1/task_31/b3_s2_31_elu_optimized_indexing/base/base.cu:11:15: warning: narrowing conversion from 'unsigned int' to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
11 | int idx = blockIdx.x * blockDim.x + threadIdx.x;
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250202_optimize_b10_s4_e0_sweep/level_1/task_31/b3_s2_31_elu_optimized_indexing/base/base.cu:12:18: warning: narrowing conversion from 'unsigned int' to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
12 | int stride = blockDim.x * gridDim.x;
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250202_optimize_b10_s4_e0_sweep/level_1/task_31/b3_s2_31_elu_optimized_indexing/base/base.cu:20:38: 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]
20 | torch::Tensor elu_cuda(torch::Tensor x, float alpha) {
| ^
| const &
/home/robert_sakana_ai/llm_cuda/experiments/20250202_optimize_b10_s4_e0_sweep/level_1/task_31/b3_s2_31_elu_optimized_indexing/base/base.cu:23:13: warning: narrowing conversion from 'int64_t' (aka 'long') to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
23 | int n = x.numel();
| ^