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29_Softplusoptimized_softplus_cuda_base

Level 1 • Task 29
import torch
import torch.nn as nn
import torch.nn.functional as F


def module_fn(x: torch.Tensor) -> torch.Tensor:
    """
    Applies Softplus activation to the input tensor.

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

    Returns:
        torch.Tensor: Output tensor with Softplus applied, same shape as input.
    """
    return F.softplus(x)


class Model(nn.Module):
    """
    Simple model that performs a Softplus activation.
    """

    def __init__(self):
        super(Model, self).__init__()

    def forward(self, x: torch.Tensor, fn=module_fn) -> torch.Tensor:
        return fn(x)


batch_size = 16
dim = 16384


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


def get_init_inputs():
    return []  # No special initialization inputs needed
import torch
import torch.nn as nn

class Model(nn.Module):
    """
    Simple model that performs a Softplus activation.
    """
    def __init__(self):
        super(Model, self).__init__()
    
    def forward(self, x: torch.Tensor) -> torch.Tensor:
        """
        Applies Softplus activation to the input tensor.

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

        Returns:
            torch.Tensor: Output tensor with Softplus applied, same shape as input.
        """
        return torch.nn.functional.softplus(x)

batch_size = 16
dim = 16384

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

def get_init_inputs():
    return []  # No special initialization inputs needed

Kernel Information

Related Kernels (Level 1, Task 29 • 29_Softplus)

Rank Kernel Name Runtime (ms) Speedup Native Speedup Compile
🥇 softplus_modular_base_base 0.01 1.16 4.88
🥇 warp_and_alignment_optimized_softplus_edit_1 0.01 1.16 4.88
🥇 branchless_softplus_edit_1 0.01 1.16 4.88
🥇 warp_optimized_softplus_base 0.01 1.16 4.88
5 softplus_unrolled_base_base 0.01 0.99 4.18
5 softplus_coalesced_base 0.01 0.99 4.18
5 softplus_2d_block_thread_base 0.01 0.99 4.18
5 optimized_softplus_cuda_base 0.01 0.99 4.18
5 softplus_coalesced_memory_access_base 0.01 0.99 4.18
5 softplus_tuned_indexing_base_base 0.01 0.99 4.18
5 softplus_blockstride_base 0.01 0.99 4.18
5 softplus_loop_unroll_base_base 0.01 0.99 4.18
5 softplus_branchless_base 0.01 0.99 4.18
5 softplus_blocksize_experiment_base 0.01 0.99 4.18
5 softplus_unrolled_base 0.01 0.99 4.18
5 softplus_constant_memory_base_base 0.01 0.99 4.18
5 optimized_softplus_cuda_base 0.01 0.99 4.18
5 29_Softplus 0.01 0.99 4.18
5 softplus_constant_memory_base 0.01 0.99 4.18
5 optimized_softplus_base 0.01 0.99 4.18
#include <torch/extension.h>
#include <cuda.h>
#include <cuda_runtime.h>
#include <type_traits>

// Threshold constants in constant memory
__constant__ float c_upper_threshold_float = 20.0f;
__constant__ float c_lower_threshold_float = -20.0f;
__constant__ double c_upper_threshold_double = 20.0;
__constant__ double c_lower_threshold_double = -20.0;

template <typename scalar_t>
__device__ __forceinline__ scalar_t compute_softplus(const scalar_t x) {
    if constexpr (std::is_same<scalar_t, float>::value) {
        if (x > c_upper_threshold_float) return x;
        if (x < c_lower_threshold_float) return __expf(x);
        return log1pf(__expf(x));
    } else {
        if (x > c_upper_threshold_double) return x;
        if (x < c_lower_threshold_double) return exp(x);
        return log1p(exp(x));
    }
}

template <typename scalar_t>
__global__ void softplus_kernel_optimized(
    const scalar_t* __restrict__ input,
    scalar_t* __restrict__ output,
    const int size) {
    
    const int tid = threadIdx.x;
    int idx = blockIdx.x * blockDim.x * 4 + tid;
    const scalar_t* input_block = input + blockIdx.x * blockDim.x * 4;
    scalar_t* output_block = output + blockIdx.x * blockDim.x * 4;

    // Use shared memory for coalesced memory access
    __shared__ scalar_t shared_input[1024];
    
    // Load data into shared memory
    #pragma unroll
    for (int i = 0; i < 4; i++) {
        if (idx + i * blockDim.x < size) {
            shared_input[tid + i * blockDim.x] = input_block[tid + i * blockDim.x];
        }
    }
    __syncthreads();

    // Process data from shared memory
    #pragma unroll
    for (int i = 0; i < 4; i++) {
        if (idx + i * blockDim.x < size) {
            output_block[tid + i * blockDim.x] = compute_softplus(shared_input[tid + i * blockDim.x]);
        }
    }
}

torch::Tensor softplus_cuda_forward(torch::Tensor input) {
    auto output = torch::empty_like(input);
    const int size = input.numel();
    const int threads = 256;
    const int blocks = (size + threads * 4 - 1) / (threads * 4);

    AT_DISPATCH_FLOATING_TYPES(input.scalar_type(), "softplus_forward_cuda", ([&] {
        softplus_kernel_optimized<scalar_t><<<blocks, threads>>>(
            input.data_ptr<scalar_t>(),
            output.data_ptr<scalar_t>(),
            size);
    }));

    return output;
}

PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
    m.def("forward", &softplus_cuda_forward, "Softplus forward (CUDA)");
}
Performance Metrics
Metric Value Unit Variance Samples
Executed Ipc Active 1.206 inst/cycle 0.001 5
Executed Ipc Elapsed 0.564 inst/cycle 0.000 5
Issue Slots Busy 30.648 % 1.052 5
Issued Ipc Active 1.224 inst/cycle 0.002 5
SM Busy 30.648 % 1.052 5
Memory Throughput 257268295374.282 byte/second 17749528052329951232.000 5
Mem Busy 12.188 % 0.039 5
Max Bandwidth 11.306 % 0.040 5
L1/TEX Hit Rate 0.000 % 0.000 5
L2 Hit Rate 67.380 % 0.095 5
Mem Pipes Busy 5.988 % 0.012 5
Warp Cycles Per Issued Instruction 12.076 cycle 0.005 5
Warp Cycles Per Executed Instruction 12.280 cycle 0.005 5
Avg. Active Threads Per Warp 32.000 0.000 5
Avg. Not Predicated Off Threads Per Warp 30.360 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 20.000 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 23.586 % 0.001 5
Achieved Active Warps Per SM 15.096 warp 0.001 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.
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 (23.6%) 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 2190813.28 μs
Device Time 40.38 μs
Self CPU Time 40.58 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 2190772.69 μs
Device Time 40.38 μs
Self CPU Time 103.96 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 2190950.78 μs
Device Time 0.00 μs
Self CPU Time 670.99 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 2166599.69 μs
Device Time 0.00 μs
Self CPU Time 2166599.69 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 234556.11 μs
Device Time 314.49 μs
Self CPU Time 234556.11 μs
Self Device Time 314.49 μs
CPU Memory Usage 0 B
Device Memory Usage 0 B
Self CPU Memory Usage 0 B
Self Device Memory Usage 0 B
void softplus_kernel_optimized<float>(float const*, float*, int)
CPU Time 0.00 μs
Device Time 751.75 μs
Self CPU Time 0.00 μs
Self Device Time 751.75 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 631.52 μs
Device Time 472.57 μs
Self CPU Time 631.52 μs
Self Device Time 472.57 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 222054.44 μs
Device Time 18154.37 μs
Self CPU Time 373.60 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 221682.56 μs
Device Time 18154.37 μs
Self CPU Time 503.31 μs
Self Device Time 18154.37 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 18154.37 μs
Self CPU Time 0.00 μs
Self Device Time 18154.37 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
45280 warnings generated when compiling for host.
Suppressed 45321 warnings (45274 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_29/b8_s2_optimized_softplus_cuda/base/base.cu:31:21 bugprone-narrowing-conversions
31 | const int tid = threadIdx.x;
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250202_optimize_b10_s4_e0_sweep/level_1/task_29/b8_s2_optimized_softplus_cuda/base/base.cu:32:15: warning: narrowing conversion from 'unsigned int' to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
32 | int idx = blockIdx.x * blockDim.x * 4 + tid;
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250202_optimize_b10_s4_e0_sweep/level_1/task_29/b8_s2_optimized_softplus_cuda/base/base.cu:59:22: warning: narrowing conversion from 'int64_t' (aka 'long') to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
59 | const int size = input.numel();
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250202_optimize_b10_s4_e0_sweep/level_1/task_29/b8_s2_optimized_softplus_cuda/base/base.cu:63:5: 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]
63 | AT_DISPATCH_FLOATING_TYPES(input.scalar_type(), "softplus_forward_cuda", ([&] {
| ^
/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__, \
| ^