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53_Gemm_Scaling_Hardtanh_GELU53gemm_scaling_hardtanh_gelu_fast_base

Level 2 • Task 53
import torch
import torch.nn as nn
import torch.nn.functional as F


def module_fn(
    x: torch.Tensor,
    scaling_factor: float,
    hardtanh_min: float,
    hardtanh_max: float,
    weight: torch.Tensor,
    bias: torch.Tensor,
) -> torch.Tensor:
    """
    Applies GEMM, scaling, hardtanh and GELU activation.

    Args:
        x (torch.Tensor): Input tensor of shape (batch_size, in_features)
        scaling_factor (float): Factor to scale the GEMM output
        hardtanh_min (float): Minimum value for hardtanh
        hardtanh_max (float): Maximum value for hardtanh
        weight (torch.Tensor): Weight matrix of shape (out_features, in_features)
        bias (torch.Tensor): Bias vector of shape (out_features)

    Returns:
        torch.Tensor: Output tensor after applying GEMM, scaling, hardtanh and GELU,
            with shape (batch_size, out_features)
    """
    x = F.linear(x, weight, bias)
    x = x * scaling_factor
    x = F.hardtanh(x, min_val=hardtanh_min, max_val=hardtanh_max)
    x = F.gelu(x)
    return x


class Model(nn.Module):
    """
    Model that performs a GEMM, scaling, hardtanh, and GELU activation.
    """

    def __init__(
        self, in_features, out_features, scaling_factor, hardtanh_min, hardtanh_max
    ):
        super(Model, self).__init__()
        gemm = nn.Linear(in_features, out_features)
        self.weight = nn.Parameter(gemm.weight)
        self.bias = nn.Parameter(gemm.bias)
        self.scaling_factor = scaling_factor
        self.hardtanh_min = hardtanh_min
        self.hardtanh_max = hardtanh_max

    def forward(self, x, fn=module_fn):
        return fn(
            x,
            self.scaling_factor,
            self.hardtanh_min,
            self.hardtanh_max,
            self.weight,
            self.bias,
        )


batch_size = 128
in_features = 1024
out_features = 512
scaling_factor = 0.5
hardtanh_min = -2
hardtanh_max = 2


def get_inputs():
    return [torch.randn(batch_size, in_features)]


def get_init_inputs():
    return [in_features, out_features, scaling_factor, hardtanh_min, hardtanh_max]
import torch
import torch.nn as nn

class Model(nn.Module):
    """
    Model that performs a GEMM, scaling, hardtanh, and GELU activation.
    """
    def __init__(self, in_features, out_features, scaling_factor, hardtanh_min, hardtanh_max):
        super(Model, self).__init__()
        self.gemm = nn.Linear(in_features, out_features)
        self.scaling_factor = scaling_factor
        self.hardtanh = nn.Hardtanh(min_val=hardtanh_min, max_val=hardtanh_max)
        self.gelu = nn.GELU()

    def forward(self, x):
        x = self.gemm(x)
        x = x * self.scaling_factor
        x = self.hardtanh(x)
        x = self.gelu(x)
        return x

batch_size = 128
in_features = 1024
out_features = 512
scaling_factor = 0.5
hardtanh_min = -2
hardtanh_max = 2

def get_inputs():
    return [torch.randn(batch_size, in_features)]

def get_init_inputs():
    return [in_features, out_features, scaling_factor, hardtanh_min, hardtanh_max]

Kernel Information

Related Kernels (Level 2, Task 53 • 53_Gemm_Scaling_Hardtanh_GELU)

#include <torch/extension.h>
#include <cuda.h>
#include <cuda_runtime.h>

// This kernel applies scaling, Hardtanh and GELU activation using a grid-stride loop.
// Note: No shared memory is used so __syncthreads() is not required.

template <typename scalar_t>
__global__ void fused_activation_kernel_fast(
    scalar_t* x,
    scalar_t scaling_factor,
    scalar_t hardtanh_min,
    scalar_t hardtanh_max,
    int64_t numel) {
  int idx = blockIdx.x * blockDim.x + threadIdx.x;
  int stride = blockDim.x * gridDim.x;
  for (int i = idx; i < numel; i += stride) {
    scalar_t val = x[i];
    // Scaling
    val = val * scaling_factor;
    // Hardtanh
    val = min(max(val, hardtanh_min), hardtanh_max);
    // GELU approximation
    const scalar_t c = static_cast<scalar_t>(0.044715);
    const scalar_t sqrt_2_over_pi = static_cast<scalar_t>(0.7978845608028654); // sqrt(2.0 / pi)
    scalar_t x_cube = val * val * val;
    scalar_t tanh_arg = sqrt_2_over_pi * (val + c * x_cube);
    scalar_t tanh_res = tanh(tanh_arg);
    val = static_cast<scalar_t>(0.5) * val * (static_cast<scalar_t>(1.0) + tanh_res);
    x[i] = val;
  }
}

void fused_activation_cuda(
    torch::Tensor& x,
    double scaling_factor,
    double hardtanh_min,
    double hardtanh_max) {
  const auto numel = x.numel();
  const int threads = 1024;
  const int blocks = (numel + threads - 1) / threads;

  AT_DISPATCH_FLOATING_TYPES(x.scalar_type(), "fused_activation_cuda", ([&] {
    fused_activation_kernel_fast<scalar_t><<<blocks, threads>>>(
        x.data_ptr<scalar_t>(),
        static_cast<scalar_t>(scaling_factor),
        static_cast<scalar_t>(hardtanh_min),
        static_cast<scalar_t>(hardtanh_max),
        numel);
  }));
}

torch::Tensor module_fn_forward(
    torch::Tensor x,
    double scaling_factor,
    double hardtanh_min,
    double hardtanh_max,
    torch::Tensor weight,
    torch::Tensor bias) {

  // Ensure inputs are contiguous and on CUDA
  x = x.contiguous().cuda();
  weight = weight.contiguous().cuda();
  bias = bias.contiguous().cuda();

  // Linear transformation: x = x @ weight.T + bias
  auto xw = torch::matmul(x, weight.t()) + bias;

  // Apply fused activation functions
  fused_activation_cuda(xw, scaling_factor, hardtanh_min, hardtanh_max);

  return xw;
}

PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
  m.def("forward", &module_fn_forward, "Module function forward (CUDA)");
}
Performance Metrics
Metric Value Unit Variance Samples
Executed Ipc Active 0.846 inst/cycle 0.004 5
Executed Ipc Elapsed 0.156 inst/cycle 0.000 5
Issue Slots Busy 23.014 % 2.623 5
Issued Ipc Active 0.922 inst/cycle 0.004 5
SM Busy 23.014 % 2.623 5
Memory Throughput 78061840308.370 byte/second 5854716052622974976.000 5
Mem Busy 10.948 % 0.104 5
Max Bandwidth 6.982 % 0.044 5
L1/TEX Hit Rate 50.000 % 0.000 5
L2 Hit Rate 81.850 % 0.164 5
Mem Pipes Busy 1.738 % 0.003 5
Warp Cycles Per Issued Instruction 29.400 cycle 0.027 5
Warp Cycles Per Executed Instruction 32.048 cycle 0.034 5
Avg. Active Threads Per Warp 30.140 0.000 5
Avg. Not Predicated Off Threads Per Warp 28.950 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 4.000 block 0.000 5
Block Limit Shared Mem 8.000 block 0.000 5
Block Limit Warps 2.000 block 0.000 5
Theoretical Active Warps per SM 64.000 warp 0.000 5
Theoretical Occupancy 100.000 % 0.000 5
Achieved Occupancy 45.026 % 0.778 5
Achieved Active Warps Per SM 28.818 warp 0.317 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 (45.4%) 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 326637.84 μs
Device Time 178.50 μs
Self CPU Time 10002.86 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 316634.98 μs
Device Time 178.50 μs
Self CPU Time 120.75 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::matmul
CPU Time 309310.31 μs
Device Time 125462.86 μs
Self CPU Time 9084.69 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
aten::mm
CPU Time 300225.62 μs
Device Time 125462.86 μs
Self CPU Time 175472.98 μs
Self Device Time 125462.86 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 380349.81 μs
Device Time 12800.51 μs
Self CPU Time 380349.81 μs
Self Device Time 12800.51 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 336896.41 μs
Device Time 676752.16 μs
Self CPU Time 16038.89 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 320859.50 μs
Device Time 676752.16 μs
Self CPU Time 19070.45 μs
Self Device Time 676752.16 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 676752.16 μs
Self CPU Time 0.00 μs
Self Device Time 676752.16 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
45286 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/20250207_optimize_b5_s4_e1_sweep/level_2/task_53/b1_s1_53gemm_scaling_hardtanh_gelu_fast/base/base.cu:11:5 bugprone-easily-swappable-parameters
11 | scalar_t scaling_factor,
| ^~~~~~~~~~~~~~~~~~~~~~~~
12 | scalar_t hardtanh_min,
| ~~~~~~~~~~~~~~~~~~~~~
/home/robert_sakana_ai/llm_cuda/experiments/20250207_optimize_b5_s4_e1_sweep/level_2/task_53/b1_s1_53gemm_scaling_hardtanh_gelu_fast/base/base.cu:11:14: note: the first parameter in the range is 'scaling_factor'
11 | scalar_t scaling_factor,
| ^~~~~~~~~~~~~~
/home/robert_sakana_ai/llm_cuda/experiments/20250207_optimize_b5_s4_e1_sweep/level_2/task_53/b1_s1_53gemm_scaling_hardtanh_gelu_fast/base/base.cu:12:14: note: the last parameter in the range is 'hardtanh_min'
12 | scalar_t hardtanh_min,
| ^~~~~~~~~~~~
/home/robert_sakana_ai/llm_cuda/experiments/20250207_optimize_b5_s4_e1_sweep/level_2/task_53/b1_s1_53gemm_scaling_hardtanh_gelu_fast/base/base.cu:15:13: warning: narrowing conversion from 'unsigned int' to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
15 | int idx = blockIdx.x * blockDim.x + threadIdx.x;
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250207_optimize_b5_s4_e1_sweep/level_2/task_53/b1_s1_53gemm_scaling_hardtanh_gelu_fast/base/base.cu:16:16: warning: narrowing conversion from 'unsigned int' to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
16 | int stride = blockDim.x * gridDim.x;
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250207_optimize_b5_s4_e1_sweep/level_2/task_53/b1_s1_53gemm_scaling_hardtanh_gelu_fast/base/base.cu:41:22: warning: narrowing conversion from 'int64_t' (aka 'long') to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
41 | const int blocks = (numel + threads - 1) / threads;
| ^
/home/robert_sakana_ai/llm_cuda/experiments/20250207_optimize_b5_s4_e1_sweep/level_2/task_53/b1_s1_53gemm_scaling_hardtanh_gelu_fast/base/base.cu:43:3: 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]
43 | AT_DISPATCH_FLOATING_TYPES(x.scalar_type(), "fused_activation_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__, \
| ^