gpt-5.5-priority · original · l12_all_gpt
correct 57_Conv2d_ReLU_HardSwish.py
model
gpt-5.5-priority
turns / max
13 / 15
tool calls
13
tokens (total)
0
wall clock
—
truncated
no
backend
cuda fp32
variant
original
runtime
1.52 μs
ref runtime
3.81 μs
speedup
2.51x
started
2026-05-04T09:39:48Z
timingkernelbench.timing
kernel runtime
1.52 μs
ref runtime
3.81 μs
speedup
2.51x
kernel mean / median / std
1.52 / — / 0.67 μs
ref mean / median / std
3.81 / — / 7.34 μs
numerical precisioneval_kernel_against_ref
max abs error
1.19e-07
mean abs error
2.20e-09
max rel error
1.79e-07
mean rel error
1.58e-08
gpu memoryextended_metrics.measure_memory
kernel peak
593.16 MB
ref peak
1585.41 MB
kernel / ref
0.37x
kernel launches / fusiontorch.profiler
kernel launches
7
ref launches
14
fusion ratio (ref / kernel)
2.00x
total cuda time
5267 μs
energyNVML (pynvml)
kernel mJ / run
726.06
ref mJ / run
484.22
ratio (ref / kernel)
0.67x
avg power
500.03 W
ref avg power
160.70 W
SOL (speed-of-light)nsight_hardware_counters
SOL score (0–1)
1.000
dram util %
100.0%
compute util %
75.3%
bottleneck
memory-bound
dominant pipe
FP32
arithmetic intensity
—
ridge point
20.00
roofline / occupancynsight_hardware_counters
dram bandwidth
6154.42 GB/s
dram util %
100.0%
fp32 tflops
—
fp32 util %
—
fp16 tflops
—
occupancy %
181.2%
bottleneck
memory-bound
dominant pipe %
75.3%
arithmetic intensity
—
ridge point
20.00
L1 hit %
—
L2 hit %
192.2%
ld sectors / req
23.21
st sectors / req
—
regs / thread
297
smem / block
36352 B
block size
512
peak bw
3350.00 GB/s
peak fp32 tflops
67.00
peak fp16 tflops
1979.00
warp stalls (top 5)nsight
long_scoreboard
8155.6%
short_scoreboard
132.8%
mio_throttle
9.1%
reference PyTorch source (the prompt the agent sees)
import torch
import torch.nn as nn

class Model(nn.Module):
    """
    Simple model that performs a convolution, applies ReLU, and applies HardSwish activation.
    """
    def __init__(self, in_channels, out_channels, kernel_size):
        super(Model, self).__init__()
        self.conv = nn.Conv2d(in_channels, out_channels, kernel_size)

    def forward(self, x):
        x = self.conv(x)
        x = torch.relu(x)
        x = x * torch.clamp((x + 3) / 6, 0, 1)
        return x

batch_size = 128
in_channels = 8
out_channels = 64
height, width = 128, 128
kernel_size = 3

def get_inputs():
    return [torch.rand(batch_size, in_channels, height, width)]

def get_init_inputs():
    return [in_channels, out_channels, kernel_size]
turn 010.8s turn · 10.8s LLM · 0.0s tools
call → get_gpu_specs
callget_gpu_specs {}
result ← get_gpu_specs (ok)
okget_gpu_specs GPU specs for NVIDIA H100 80GB HBM3: total memory (runtime): 79.1 GB spec entry: H100 GPU Architecture: Hopper GPU Memory: 80GB Memory Bandwidth: 3.35 TB/s FP64 TFLOPS: 34 FP64 Tensor Core TFLOPS: 67 FP32 TFLOPS: 67 TF32 Tensor Core TFLOPS: 989 with sparsity BFLOAT16 Tensore Core TFLOPS: 1979 with sparsity FP16 Tensor Core TFLOPS: 1979 with sparsity FP8 Tensor Core TFLOPS: 3958 with sparsity INT8 Tensor Core TOPS: 3958 with sparsity Register File Size: 64K 32-bit registers per SM Maximum number of registers per thread: 255 Maximum number of thread blocks per SM: 32 Shared memory capacity per SM: 228 KB Maximum shared memory per thread block: 227 KB
turn 1 · 1 tool call(s) · 49.8s turn · 49.8s LLM · 10,038 chars (click to expand)
turn 149.8s turn · 49.8s LLM · 0.0s tools
reasoning
**Analyzing thread mapping** I'm thinking about how threads might be mapped. If I consider 256 threads, that could translate to 8 warps. Could each thread compute one measurement and one computation? The math seems messy—16 million times 64 gives an overwhelming number of outputs per block. It sounds more feasible if 256 threads each compute four outputs instead. Maybe I can map those threads to 16 million and 16 computation groups, having each thread work on four channels. **Clarifying tensor storage** I'm working through some tensor storage considerations, specifically with output offsets in a layout. I think using a formula like ((n*64 + co)*Ho + oh)*Wo + ow could work, especially for computing layouts. I wonder if switching to a channels_last format would fix issues with coalescing. I'm also considering the implications of striding and shape compatibility with PyTorch, and whether custom allocation could help optimize storage. It seems like there might be a solution here!
call → compile_kernel
callcompile_kernel { "kernel_code": "import torch\nimport torch.nn as nn\nfrom torch.utils.cpp_extension import load_inline\n\n_cpp_src = r\"\"\"\n#include <torch/extension.h>\ntorch::Tensor conv_relu_hswish_forward(torch::Tensor x, torch::Tensor weight, torch::Tensor bias);\n\"\"\"\n\n_cuda_src = r\"\"\"\n#include <torch/extension.h>\n#include <cuda.h>\n#include <cuda_runtime.h>\n\n#define CHECK_CUDA(x) TORCH_CHECK(x.is_cuda(), #x \" must be a CUDA tensor\")\n#define CHECK_CONTIGUOUS(x) TORCH_CHECK(x.is_contiguous(), #x \" must be contiguous\")\n\n__global__ void pack_weight_kernel(const float* __restrict__ w, float* __restrict__ pw) {\n int idx = blockIdx.x * blockDim.x + threadIdx.x;\n if (idx < 64*72) {\n int k = idx / 64;\n int co = idx - k * 64;\n pw[idx] = w[co * 72 + k];\n }\n}\n\n__global__ void conv_act_kernel(const float* __restrict__ x,\n const float* __restrict__ pw,\n const float* __restrict__ bias,\n float* __restrict__ out) {\n constexpr int BM = 32;\n constexpr int K = 72;\n constexpr int CO = 64;\n constexpr int H = 128;\n constexpr int W = 128;\n constexpr int HO = 126;\n constexpr int WO = 126;\n constexpr int SP = HO * WO;\n constexpr int M = 128 * SP;\n __shared__ float sh[BM * K];\n\n int tile_m = blockIdx.x * BM;\n int tid = threadIdx.x;\n\n // Cooperatively load the implicit im2col tile into shared memory.\n for (int idx = tid; idx < BM*K; idx += blockDim.x) {\n int mi = idx / K;\n int k = idx - mi * K;\n int mg = tile_m + mi;\n float v = 0.0f;\n if (mg < M) {\n int t = mg;\n int ow = t % WO;\n t /= WO;\n int oh = t % HO;\n int n = t / HO;\n int c = k / 9;\n int kk = k - c * 9;\n int r = kk / 3;\n int s = kk - r * 3;\n v = x[((n * 8 + c) * H + (oh + r)) * W + (ow + s)];\n }\n sh[idx] = v;\n }\n __syncthreads();\n\n int mi = tid >> 3; // 0..31\n int cg = tid & 7; // 0..7, each computes 8 adjacent channels\n int co0 = cg << 3;\n int mg = tile_m + mi;\n if (mi < BM && mg < M) {\n float a0 = bias[co0 + 0];\n float a1 = bias[co0 + 1];\n float a2 = bias[co0 + 2];\n float a3 = bias[co0 + 3];\n float a4 = bias[co0 + 4];\n float a5 = bias[co0 + 5];\n float a6 = bias[co0 + 6];\n float a7 = bias[co0 + 7];\n #pragma unroll\n for (int k = 0; k < K; ++k) {\n float xv = sh[mi*K + k];\n const float* wp = pw + k*CO + co0;\n a0 = fmaf(xv, wp[0], a0);\n a1 = fmaf(xv, wp[1], a1);\n a2 = fmaf(xv, wp[2], a2);\n a3 = fmaf(xv, wp[3], a3);\n a4 = fmaf(xv, wp[4], a4);\n a5 = fmaf(xv, wp[5], a5);\n a6 = fmaf(xv, wp[6], a6);\n a7 = fmaf(xv, wp[7], a7);\n }\n int t = mg;\n int ow = t % WO;\n t /= WO;\n int oh = t % HO;\n int n = t / HO;\n int base = ((n * HO + oh) * WO + ow) * CO + co0; // channels-last physical storage\n float vals[8] = {a0,a1,a2,a3,a4,a5,a6,a7};\n #pragma unroll\n for (int i = 0; i < 8; ++i) {\n float z = vals[i];\n z = z > 0.0f ? z : 0.0f;\n float y = (z >= 3.0f) ? z : (z * (z + 3.0f) * 0.16666666666666666f);\n out[base + i] = y;\n }\n }\n}\n\ntorch::Tensor conv_relu_hswish_forward(torch::Tensor x, torch::Tensor weight, torch::Tensor bias) {\n CHECK_CUDA(x); CHECK_CUDA(weight); CHECK_CUDA(bias);\n CHECK_CONTIGUOUS(x); CHECK_CONTIGUOUS(weight); CHECK_CONTIGUOUS(bias);\n TORCH_CHECK(x.scalar_type() == torch::kFloat32, \"x must be float32\");\n auto opts = x.options();\n auto out = torch::empty_strided({128, 64, 126, 126}, {64*126*126, 1, 64*126, 64}, opts);\n auto packed = torch::empty({72, 64}, opts);\n cudaStream_t stream = at::cuda::getCurrentCUDAStream();\n pack_weight_kernel<<<18, 256, 0, stream>>>(weight.data_ptr<float>(), packed.data_ptr<float>());\n int blocks = (128*126*126 + 31) / 32;\n conv_act_kernel<<<blocks, 256, 0, stream>>>(x.data_ptr<float>(), packed.data_ptr<float>(), bias.data_ptr<float>(), out.data_ptr<float>());\n return out;\n}\n\"\"\"\n\n_ext = load_inline(name=\"conv_relu_hswish_ext_v1\", cpp_sources=_cpp_src, cuda_sources=_cuda_src,\n functions=[\"conv_relu_hswish_forward\"], extra_cuda_cflags=[\"-O3\", \"--use_fast_math\"], verbose=False)\n\nclass ModelNew(nn.Module):\n def __init__(self, in_channels, out_channels, kernel_size):\n super(ModelNew, self).__init__()\n self.conv = nn.Conv2d(in_channels, out_channels, kernel_size)\n def forward(self, x):\n return _ext.conv_relu_hswish_forward(x, self.conv.weight, self.conv.bias)\n" }
result ← compile_kernel (fail)
failcompile_kernel compile_kernel FAILED: RuntimeError. RuntimeError: Error building extension 'conv_relu_hswish_ext_v1': [1/3] /opt/conda/bin/x86_64-conda-linux-gnu-c++ -MMD -MF main.o.d -DTORCH_EXTENSION_NAME=conv_relu_hswish_ext_v1 -DTORCH_API_INCLUDE_EXTENSION_H -isystem /scratch/abaner/KernelBench/.venv/lib/python3.10/site-packages/torch/include -isystem /scratch/abaner/KernelBench/.venv/lib/python3.10/site-packages/torch/include/torch/csrc/api/include -isystem /usr/local/cuda/include -isystem /opt/conda/include/python3.10 -fPIC -std=c++17 -c /scratch/abaner/KernelBench/runs/l12_all_gpt/original/gpt-5.5-priority/level_2_problem_57_cache/k_b2f4a02c77b5/conv_relu_hswish_ext_v1/main.cpp -o main.o [2/3] /usr/local/cuda/bin/nvcc -MD -MF cuda.cuda.o.d -ccbin /opt/conda/bin/x86_64-conda-linux-gnu-cc -DTORCH_EXTENSION_NAME=conv_relu_hswish_ext_v1 -DTORCH_API_INCLUDE_EXTENSION_H -isystem /scratch/abaner/KernelBench/.venv/lib/python3.10/site-packages/torch/include -isystem /scratch/abaner/KernelBench/.venv/lib/python3.10/site-packages/torch/include/torch/csrc/api/include -isystem /usr/local/cuda/include -isystem /opt/conda/include/python3.10 -D__CUDA_NO_HALF_OPERATORS__ -D__CUDA_NO_HALF_CONVERSIONS__ -D__CUDA_NO_BFLOAT16_CONVERSIONS__ -D__CUDA_NO_HALF2_OPERATORS__ --expt-relaxed-constexpr -gencode=arch=compute_90,code=compute_90 -gencode=arch=compute_90,code=sm_90 --compiler-options '-fPIC' -O3 --use_fast_math -std=c++17 -c /scratch/abaner/KernelBench/runs/l12_all_gpt/original/gpt-5.5-priority/level_2_problem_57_cache/k_b2f4a02c77b5/conv_relu_hswish_ext_v1/cuda.cu -o cuda.cuda.o FAILED: [code=2] cuda.cuda.o /usr/local/cuda/bin/nvcc -MD -MF cuda.cuda.o.d -ccbin /opt/conda/bin/x86_64-conda-linux-gnu-cc -DTORCH_EXTENSION_NAME=conv_relu_hswish_ext_v1 -DTORCH_API_INCLUDE_EXTENSION_H -isystem /scratch/abaner/KernelBench/.venv/lib/python3.10/site-packages/torch/include -isystem /scratch/abaner/KernelBench/.venv/lib/python3.10/site-packages/torch/include/torch/csrc/api/include -isystem /usr/local/cuda/include -isystem /opt/conda/include/python3.10 -D__CUDA_NO_HALF_OPERATORS__ -D__CUDA_NO_HALF_CONVERSIONS__ -D__CUDA_NO_BFLOAT16_CONVERSIONS__ -D__CUDA_NO_HALF2_OPERATORS__ --expt-relaxed-constexpr -gencode=arch=compute_90,code=compute_90 -gencode=arch=compute_90,code=sm_90 --compiler-options '-fPIC' -O3 --use_fast_math -std=c++17 -c /scratch/abaner/KernelBench/runs/l12_all_gpt/original/gpt-5.5-priority/level_2_problem_57_cache/k_b2f4a02c77b5/conv_relu_hswish_ext_v1/cuda.cu -o cuda.cuda.o nvcc warning : incompatible redefinition for option 'compiler-bindir', the last value of this option was used /scratch/abaner/KernelBench/runs/l12_all_gpt/original/gpt-5.5-priority/level_2_problem_57_cache/k_b2f4a02c77b5/conv_relu_hswish_ext_v1/cuda.cu(111): error: namespace "at::cuda" has no member "getCurrentCUDAStream" cudaStream_t stream = at::cuda::getCurrentCUDAStream(); ^ 1 error detected in the compilation of "/scratch/abaner/KernelBench/runs/l12_all_gpt/original/gpt-5.5-priority/level_2_problem_57_cache/k_b2f4a02c77b5/conv_relu_hswish_ext_v1/cuda.cu". ninja: build stopped: subcommand failed.
turn 211.7s turn · 11.7s LLM · 0.0s tools
call → compile_kernel
callcompile_kernel { "kernel_code": "import torch\nimport torch.nn as nn\nfrom torch.utils.cpp_extension import load_inline\n\n_cpp_src = r\"\"\"\n#include <torch/extension.h>\ntorch::Tensor conv_relu_hswish_forward(torch::Tensor x, torch::Tensor weight, torch::Tensor bias);\n\"\"\"\n\n_cuda_src = r\"\"\"\n#include <torch/extension.h>\n#include <ATen/cuda/CUDAContext.h>\n#include <cuda.h>\n#include <cuda_runtime.h>\n\n#define CHECK_CUDA(x) TORCH_CHECK(x.is_cuda(), #x \" must be a CUDA tensor\")\n#define CHECK_CONTIGUOUS(x) TORCH_CHECK(x.is_contiguous(), #x \" must be contiguous\")\n\n__global__ void pack_weight_kernel(const float* __restrict__ w, float* __restrict__ pw) {\n int idx = blockIdx.x * blockDim.x + threadIdx.x;\n if (idx < 64*72) {\n int k = idx / 64;\n int co = idx - k * 64;\n pw[idx] = w[co * 72 + k];\n }\n}\n\n__global__ void conv_act_kernel(const float* __restrict__ x,\n const float* __restrict__ pw,\n const float* __restrict__ bias,\n float* __restrict__ out) {\n constexpr int BM = 32;\n constexpr int K = 72;\n constexpr int CO = 64;\n constexpr int H = 128;\n constexpr int W = 128;\n constexpr int HO = 126;\n constexpr int WO = 126;\n constexpr int SP = HO * WO;\n constexpr int M = 128 * SP;\n __shared__ float sh[BM * K];\n\n int tile_m = blockIdx.x * BM;\n int tid = threadIdx.x;\n\n for (int idx = tid; idx < BM*K; idx += blockDim.x) {\n int mi = idx / K;\n int k = idx - mi * K;\n int mg = tile_m + mi;\n float v = 0.0f;\n if (mg < M) {\n int t = mg;\n int ow = t % WO;\n t /= WO;\n int oh = t % HO;\n int n = t / HO;\n int c = k / 9;\n int kk = k - c * 9;\n int r = kk / 3;\n int s = kk - r * 3;\n v = x[((n * 8 + c) * H + (oh + r)) * W + (ow + s)];\n }\n sh[idx] = v;\n }\n __syncthreads();\n\n int mi = tid >> 3;\n int cg = tid & 7;\n int co0 = cg << 3;\n int mg = tile_m + mi;\n if (mg < M) {\n float a0 = bias[co0 + 0];\n float a1 = bias[co0 + 1];\n float a2 = bias[co0 + 2];\n float a3 = bias[co0 + 3];\n float a4 = bias[co0 + 4];\n float a5 = bias[co0 + 5];\n float a6 = bias[co0 + 6];\n float a7 = bias[co0 + 7];\n #pragma unroll\n for (int k = 0; k < K; ++k) {\n float xv = sh[mi*K + k];\n const float* wp = pw + k*CO + co0;\n a0 = fmaf(xv, wp[0], a0);\n a1 = fmaf(xv, wp[1], a1);\n a2 = fmaf(xv, wp[2], a2);\n a3 = fmaf(xv, wp[3], a3);\n a4 = fmaf(xv, wp[4], a4);\n a5 = fmaf(xv, wp[5], a5);\n a6 = fmaf(xv, wp[6], a6);\n a7 = fmaf(xv, wp[7], a7);\n }\n int t = mg;\n int ow = t % WO;\n t /= WO;\n int oh = t % HO;\n int n = t / HO;\n int base = ((n * HO + oh) * WO + ow) * CO + co0;\n float vals[8] = {a0,a1,a2,a3,a4,a5,a6,a7};\n #pragma unroll\n for (int i = 0; i < 8; ++i) {\n float z = vals[i];\n z = z > 0.0f ? z : 0.0f;\n float y = (z >= 3.0f) ? z : (z * (z + 3.0f) * 0.16666666666666666f);\n out[base + i] = y;\n }\n }\n}\n\ntorch::Tensor conv_relu_hswish_forward(torch::Tensor x, torch::Tensor weight, torch::Tensor bias) {\n CHECK_CUDA(x); CHECK_CUDA(weight); CHECK_CUDA(bias);\n CHECK_CONTIGUOUS(x); CHECK_CONTIGUOUS(weight); CHECK_CONTIGUOUS(bias);\n TORCH_CHECK(x.scalar_type() == torch::kFloat32, \"x must be float32\");\n auto opts = x.options();\n auto out = torch::empty_strided({128, 64, 126, 126}, {64*126*126, 1, 64*126, 64}, opts);\n auto packed = torch::empty({72, 64}, opts);\n cudaStream_t stream = at::cuda::getCurrentCUDAStream();\n pack_weight_kernel<<<18, 256, 0, stream>>>(weight.data_ptr<float>(), packed.data_ptr<float>());\n int blocks = (128*126*126 + 31) / 32;\n conv_act_kernel<<<blocks, 256, 0, stream>>>(x.data_ptr<float>(), packed.data_ptr<float>(), bias.data_ptr<float>(), out.data_ptr<float>());\n return out;\n}\n\"\"\"\n\n_ext = load_inline(name=\"conv_relu_hswish_ext_v2\", cpp_sources=_cpp_src, cuda_sources=_cuda_src,\n functions=[\"conv_relu_hswish_forward\"], extra_cuda_cflags=[\"-O3\", \"--use_fast_math\"], verbose=False)\n\nclass ModelNew(nn.Module):\n def __init__(self, in_channels, out_channels, kernel_size):\n super(ModelNew, self).__init__()\n self.conv = nn.Conv2d(in_channels, out_channels, kernel_size)\n def forward(self, x):\n return _ext.conv_relu_hswish_forward(x, self.conv.weight, self.conv.bias)\n" }
result ← compile_kernel (ok)
okcompile_kernel compile_kernel PASSED: kernel compiled without errors.
turn 39.0s turn · 9.0s LLM · 0.0s tools
call → run_correctness
callrun_correctness { "kernel_code": "import torch\nimport torch.nn as nn\nfrom torch.utils.cpp_extension import load_inline\n\n_cpp_src = r\"\"\"\n#include <torch/extension.h>\ntorch::Tensor conv_relu_hswish_forward(torch::Tensor x, torch::Tensor weight, torch::Tensor bias);\n\"\"\"\n\n_cuda_src = r\"\"\"\n#include <torch/extension.h>\n#include <ATen/cuda/CUDAContext.h>\n#include <cuda.h>\n#include <cuda_runtime.h>\n#define CHECK_CUDA(x) TORCH_CHECK(x.is_cuda(), #x \" must be a CUDA tensor\")\n#define CHECK_CONTIGUOUS(x) TORCH_CHECK(x.is_contiguous(), #x \" must be contiguous\")\n__global__ void pack_weight_kernel(const float* __restrict__ w, float* __restrict__ pw) { int idx=blockIdx.x*blockDim.x+threadIdx.x; if(idx<64*72){int k=idx/64; int co=idx-k*64; pw[idx]=w[co*72+k];}}\n__global__ void conv_act_kernel(const float* __restrict__ x,const float* __restrict__ pw,const float* __restrict__ bias,float* __restrict__ out){\n constexpr int BM=32,K=72,CO=64,H=128,W=128,HO=126,WO=126,SP=HO*WO,M=128*SP; __shared__ float sh[BM*K]; int tile_m=blockIdx.x*BM; int tid=threadIdx.x;\n for(int idx=tid;idx<BM*K;idx+=blockDim.x){int mi=idx/K; int k=idx-mi*K; int mg=tile_m+mi; float v=0.0f; if(mg<M){int t=mg; int ow=t%WO; t/=WO; int oh=t%HO; int n=t/HO; int c=k/9; int kk=k-c*9; int r=kk/3; int s=kk-r*3; v=x[((n*8+c)*H+(oh+r))*W+(ow+s)];} sh[idx]=v;} __syncthreads();\n int mi=tid>>3; int cg=tid&7; int co0=cg<<3; int mg=tile_m+mi; if(mg<M){float a0=bias[co0],a1=bias[co0+1],a2=bias[co0+2],a3=bias[co0+3],a4=bias[co0+4],a5=bias[co0+5],a6=bias[co0+6],a7=bias[co0+7];\n #pragma unroll\n for(int k=0;k<K;++k){float xv=sh[mi*K+k]; const float* wp=pw+k*CO+co0; a0=fmaf(xv,wp[0],a0); a1=fmaf(xv,wp[1],a1); a2=fmaf(xv,wp[2],a2); a3=fmaf(xv,wp[3],a3); a4=fmaf(xv,wp[4],a4); a5=fmaf(xv,wp[5],a5); a6=fmaf(xv,wp[6],a6); a7=fmaf(xv,wp[7],a7);} int t=mg; int ow=t%WO; t/=WO; int oh=t%HO; int n=t/HO; int base=((n*HO+oh)*WO+ow)*CO+co0; float vals[8]={a0,a1,a2,a3,a4,a5,a6,a7};\n #pragma unroll\n for(int i=0;i<8;++i){float z=vals[i]; z=z>0.0f?z:0.0f; float y=(z>=3.0f)?z:(z*(z+3.0f)*0.16666666666666666f); out[base+i]=y;}}}\ntorch::Tensor conv_relu_hswish_forward(torch::Tensor x, torch::Tensor weight, torch::Tensor bias){CHECK_CUDA(x);CHECK_CUDA(weight);CHECK_CUDA(bias);CHECK_CONTIGUOUS(x);CHECK_CONTIGUOUS(weight);CHECK_CONTIGUOUS(bias); auto opts=x.options(); auto out=torch::empty_strided({128,64,126,126},{64*126*126,1,64*126,64},opts); auto packed=torch::empty({72,64},opts); cudaStream_t stream=at::cuda::getCurrentCUDAStream(); pack_weight_kernel<<<18,256,0,stream>>>(weight.data_ptr<float>(),packed.data_ptr<float>()); int blocks=(128*126*126+31)/32; conv_act_kernel<<<blocks,256,0,stream>>>(x.data_ptr<float>(),packed.data_ptr<float>(),bias.data_ptr<float>(),out.data_ptr<float>()); return out;}\n\"\"\"\n_ext=load_inline(name=\"conv_relu_hswish_ext_v2c\", cpp_sources=_cpp_src, cuda_sources=_cuda_src, functions=[\"conv_relu_hswish_forward\"], extra_cuda_cflags=[\"-O3\",\"--use_fast_math\"], verbose=False)\nclass ModelNew(nn.Module):\n def __init__(self,in_channels,out_channels,kernel_size):\n super(ModelNew,self).__init__(); self.conv=nn.Conv2d(in_channels,out_channels,kernel_size)\n def forward(self,x): return _ext.conv_relu_hswish_forward(x,self.conv.weight,self.conv.bias)\n" }
result ← run_correctness (ok)
okrun_correctness run_correctness PASSED: (5 / 5) trials all matched the reference. Numerical precision: max_abs_err=5.96e-07 mean_abs_err=1.06e-08 max_rel_err=1.99e+04
turn 48.4s turn · 8.4s LLM · 0.0s tools
call → profile_kernel
callprofile_kernel { "kernel_code": "import torch\nimport torch.nn as nn\nfrom torch.utils.cpp_extension import load_inline\n_cpp_src=r\"\"\"\n#include <torch/extension.h>\ntorch::Tensor conv_relu_hswish_forward(torch::Tensor x, torch::Tensor weight, torch::Tensor bias);\n\"\"\"\n_cuda_src=r\"\"\"\n#include <torch/extension.h>\n#include <ATen/cuda/CUDAContext.h>\n#include <cuda.h>\n#include <cuda_runtime.h>\n#define CHECK_CUDA(x) TORCH_CHECK(x.is_cuda(), #x \" must be a CUDA tensor\")\n#define CHECK_CONTIGUOUS(x) TORCH_CHECK(x.is_contiguous(), #x \" must be contiguous\")\n__global__ void pack_weight_kernel(const float* __restrict__ w,float* __restrict__ pw){int idx=blockIdx.x*blockDim.x+threadIdx.x;if(idx<64*72){int k=idx/64;int co=idx-k*64;pw[idx]=w[co*72+k];}}\n__global__ void conv_act_kernel(const float* __restrict__ x,const float* __restrict__ pw,const float* __restrict__ bias,float* __restrict__ out){constexpr int BM=32,K=72,CO=64,H=128,W=128,HO=126,WO=126,SP=HO*WO,M=128*SP;__shared__ float sh[BM*K];int tile_m=blockIdx.x*BM;int tid=threadIdx.x;for(int idx=tid;idx<BM*K;idx+=blockDim.x){int mi=idx/K;int k=idx-mi*K;int mg=tile_m+mi;float v=0.0f;if(mg<M){int t=mg;int ow=t%WO;t/=WO;int oh=t%HO;int n=t/HO;int c=k/9;int kk=k-c*9;int r=kk/3;int s=kk-r*3;v=x[((n*8+c)*H+(oh+r))*W+(ow+s)];}sh[idx]=v;}__syncthreads();int mi=tid>>3;int cg=tid&7;int co0=cg<<3;int mg=tile_m+mi;if(mg<M){float a0=bias[co0],a1=bias[co0+1],a2=bias[co0+2],a3=bias[co0+3],a4=bias[co0+4],a5=bias[co0+5],a6=bias[co0+6],a7=bias[co0+7];#pragma unroll\nfor(int k=0;k<K;++k){float xv=sh[mi*K+k];const float* wp=pw+k*CO+co0;a0=fmaf(xv,wp[0],a0);a1=fmaf(xv,wp[1],a1);a2=fmaf(xv,wp[2],a2);a3=fmaf(xv,wp[3],a3);a4=fmaf(xv,wp[4],a4);a5=fmaf(xv,wp[5],a5);a6=fmaf(xv,wp[6],a6);a7=fmaf(xv,wp[7],a7);}int t=mg;int ow=t%WO;t/=WO;int oh=t%HO;int n=t/HO;int base=((n*HO+oh)*WO+ow)*CO+co0;float vals[8]={a0,a1,a2,a3,a4,a5,a6,a7};#pragma unroll\nfor(int i=0;i<8;++i){float z=vals[i];z=z>0.0f?z:0.0f;float y=(z>=3.0f)?z:(z*(z+3.0f)*0.16666666666666666f);out[base+i]=y;}}}\ntorch::Tensor conv_relu_hswish_forward(torch::Tensor x,torch::Tensor weight,torch::Tensor bias){CHECK_CUDA(x);CHECK_CUDA(weight);CHECK_CUDA(bias);CHECK_CONTIGUOUS(x);CHECK_CONTIGUOUS(weight);CHECK_CONTIGUOUS(bias);auto opts=x.options();auto out=torch::empty_strided({128,64,126,126},{64*126*126,1,64*126,64},opts);auto packed=torch::empty({72,64},opts);cudaStream_t stream=at::cuda::getCurrentCUDAStream();pack_weight_kernel<<<18,256,0,stream>>>(weight.data_ptr<float>(),packed.data_ptr<float>());int blocks=(128*126*126+31)/32;conv_act_kernel<<<blocks,256,0,stream>>>(x.data_ptr<float>(),packed.data_ptr<float>(),bias.data_ptr<float>(),out.data_ptr<float>());return out;}\n\"\"\"\n_ext=load_inline(name=\"conv_relu_hswish_ext_v2p\",cpp_sources=_cpp_src,cuda_sources=_cuda_src,functions=[\"conv_relu_hswish_forward\"],extra_cuda_cflags=[\"-O3\",\"--use_fast_math\"],verbose=False)\nclass ModelNew(nn.Module):\n def __init__(self,in_channels,out_channels,kernel_size):\n super(ModelNew,self).__init__();self.conv=nn.Conv2d(in_channels,out_channels,kernel_size)\n def forward(self,x):return _ext.conv_relu_hswish_forward(x,self.conv.weight,self.conv.bias)\n" }
result ← profile_kernel (fail)
failprofile_kernel profile_kernel FAILED: worker exited with code 1. or: expected a ";" for(int i=0;i<8;++i){float z=vals[i];z=z>0.0f?z:0.0f;float y=(z>=3.0f)?z:(z*(z+3.0f)*0.16666666666666666f);out[base+i]=y;}}} ^ 6 errors detected in the compilation of "/scratch/abaner/KernelBench/runs/l12_all_gpt/original/gpt-5.5-priority/level_2_problem_57_cache/k_f75b95b6fdfa/conv_relu_hswish_ext_v2p/cuda.cu". ninja: build stopped: subcommand failed.
turn 524.0s turn · 24.0s LLM · 0.0s tools
reasoning
**Considering code compilation** I'm pondering whether to address the minified pragma not line issue. It might make sense to use the previous, full version instead but I wonder if that’s really necessary. Still, I definitely want to create a profile. Perhaps I could also compile the code from above for consistency? There are so many factors to balance here, and I want to get it right to ensure everything works smoothly. Let's see how this unfolds!
call → run_correctness
callrun_correctness { "kernel_code": "import torch\nimport torch.nn as nn\nfrom torch.utils.cpp_extension import load_inline\n\n_cpp_src = r\"\"\"\n#include <torch/extension.h>\ntorch::Tensor conv_relu_hswish_forward(torch::Tensor x, torch::Tensor weight, torch::Tensor bias);\n\"\"\"\n\n_cuda_src = r\"\"\"\n#include <torch/extension.h>\n#include <ATen/cuda/CUDAContext.h>\n#include <cuda.h>\n#include <cuda_runtime.h>\n#define CHECK_CUDA(x) TORCH_CHECK(x.is_cuda(), #x \" must be a CUDA tensor\")\n#define CHECK_CONTIGUOUS(x) TORCH_CHECK(x.is_contiguous(), #x \" must be contiguous\")\n\n__global__ void pack_weight_kernel(const float* __restrict__ w, float* __restrict__ pw) {\n int idx = blockIdx.x * blockDim.x + threadIdx.x;\n if (idx < 64*72) { int k = idx / 64; int co = idx - k*64; pw[idx] = w[co*72+k]; }\n}\n\n__global__ void conv_act_kernel64(const float* __restrict__ x, const float* __restrict__ pw, const float* __restrict__ bias, float* __restrict__ out) {\n constexpr int BM=64, K=72, CO=64, H=128, W=128, HO=126, WO=126, SP=HO*WO, M=128*SP;\n __shared__ float sh[BM*K];\n int tile_m = blockIdx.x * BM;\n int tid = threadIdx.x;\n for (int idx=tid; idx<BM*K; idx += blockDim.x) {\n int mi = idx / K; int k = idx - mi*K; int mg = tile_m + mi;\n float v = 0.0f;\n if (mg < M) {\n int t=mg; int ow=t%WO; t/=WO; int oh=t%HO; int n=t/HO;\n int c=k/9; int kk=k-c*9; int r=kk/3; int s=kk-r*3;\n v = x[((n*8+c)*H + (oh+r))*W + (ow+s)];\n }\n sh[idx] = v;\n }\n __syncthreads();\n int mi = tid >> 2; // 0..63\n int cg = tid & 3; // 0..3\n int co0 = cg << 4; // 16 channels per thread\n int mg = tile_m + mi;\n if (mg < M) {\n float a0=bias[co0+0], a1=bias[co0+1], a2=bias[co0+2], a3=bias[co0+3];\n float a4=bias[co0+4], a5=bias[co0+5], a6=bias[co0+6], a7=bias[co0+7];\n float a8=bias[co0+8], a9=bias[co0+9], a10=bias[co0+10], a11=bias[co0+11];\n float a12=bias[co0+12], a13=bias[co0+13], a14=bias[co0+14], a15=bias[co0+15];\n #pragma unroll\n for (int k=0; k<K; ++k) {\n float xv = sh[mi*K+k]; const float* wp = pw + k*CO + co0;\n a0=fmaf(xv,wp[0],a0); a1=fmaf(xv,wp[1],a1); a2=fmaf(xv,wp[2],a2); a3=fmaf(xv,wp[3],a3);\n a4=fmaf(xv,wp[4],a4); a5=fmaf(xv,wp[5],a5); a6=fmaf(xv,wp[6],a6); a7=fmaf(xv,wp[7],a7);\n a8=fmaf(xv,wp[8],a8); a9=fmaf(xv,wp[9],a9); a10=fmaf(xv,wp[10],a10); a11=fmaf(xv,wp[11],a11);\n a12=fmaf(xv,wp[12],a12); a13=fmaf(xv,wp[13],a13); a14=fmaf(xv,wp[14],a14); a15=fmaf(xv,wp[15],a15);\n }\n int t=mg; int ow=t%WO; t/=WO; int oh=t%HO; int n=t/HO;\n int base = ((n*HO+oh)*WO+ow)*CO + co0;\n float vals[16] = {a0,a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12,a13,a14,a15};\n #pragma unroll\n for (int i=0;i<16;++i) { float z=vals[i]; z = z>0.0f ? z : 0.0f; out[base+i] = (z>=3.0f) ? z : (z*(z+3.0f)*0.16666666666666666f); }\n }\n}\n\ntorch::Tensor conv_relu_hswish_forward(torch::Tensor x, torch::Tensor weight, torch::Tensor bias) {\n CHECK_CUDA(x); CHECK_CUDA(weight); CHECK_CUDA(bias); CHECK_CONTIGUOUS(x); CHECK_CONTIGUOUS(weight); CHECK_CONTIGUOUS(bias);\n auto opts=x.options();\n auto out=torch::empty_strided({128,64,126,126},{64*126*126,1,64*126,64},opts);\n auto packed=torch::empty({72,64},opts);\n cudaStream_t stream=at::cuda::getCurrentCUDAStream();\n pack_weight_kernel<<<18,256,0,stream>>>(weight.data_ptr<float>(), packed.data_ptr<float>());\n int blocks=(128*126*126 + 63)/64;\n conv_act_kernel64<<<blocks,256,0,stream>>>(x.data_ptr<float>(), packed.data_ptr<float>(), bias.data_ptr<float>(), out.data_ptr<float>());\n return out;\n}\n\"\"\"\n_ext=load_inline(name=\"conv_relu_hswish_ext_v3\", cpp_sources=_cpp_src, cuda_sources=_cuda_src, functions=[\"conv_relu_hswish_forward\"], extra_cuda_cflags=[\"-O3\",\"--use_fast_math\"], verbose=False)\nclass ModelNew(nn.Module):\n def __init__(self,in_channels,out_channels,kernel_size):\n super(ModelNew,self).__init__(); self.conv=nn.Conv2d(in_channels,out_channels,kernel_size)\n def forward(self,x): return _ext.conv_relu_hswish_forward(x,self.conv.weight,self.conv.bias)\n" }
result ← run_correctness (ok)
okrun_correctness run_correctness PASSED: (5 / 5) trials all matched the reference. Numerical precision: max_abs_err=5.96e-07 mean_abs_err=1.06e-08 max_rel_err=1.99e+04
turn 6 · 1 tool call(s) · 10.1s turn · 10.1s LLM · 6,409 chars (click to expand)
turn 610.1s turn · 10.1s LLM · 0.0s tools
call → profile_kernel
callprofile_kernel { "kernel_code": "import torch\nimport torch.nn as nn\nfrom torch.utils.cpp_extension import load_inline\n\n_cpp_src = r\"\"\"\n#include <torch/extension.h>\ntorch::Tensor conv_relu_hswish_forward(torch::Tensor x, torch::Tensor weight, torch::Tensor bias);\n\"\"\"\n\n_cuda_src = r\"\"\"\n#include <torch/extension.h>\n#include <ATen/cuda/CUDAContext.h>\n#include <cuda.h>\n#include <cuda_runtime.h>\n#define CHECK_CUDA(x) TORCH_CHECK(x.is_cuda(), #x \" must be a CUDA tensor\")\n#define CHECK_CONTIGUOUS(x) TORCH_CHECK(x.is_contiguous(), #x \" must be contiguous\")\n\n__global__ void pack_weight_kernel(const float* __restrict__ w, float* __restrict__ pw) {\n int idx = blockIdx.x * blockDim.x + threadIdx.x;\n if (idx < 64*72) { int k = idx / 64; int co = idx - k*64; pw[idx] = w[co*72+k]; }\n}\n\n__global__ void conv_act_kernel64(const float* __restrict__ x, const float* __restrict__ pw, const float* __restrict__ bias, float* __restrict__ out) {\n constexpr int BM=64, K=72, CO=64, H=128, W=128, HO=126, WO=126, SP=HO*WO, M=128*SP;\n __shared__ float sh[BM*K];\n int tile_m = blockIdx.x * BM;\n int tid = threadIdx.x;\n for (int idx=tid; idx<BM*K; idx += blockDim.x) {\n int mi = idx / K; int k = idx - mi*K; int mg = tile_m + mi;\n float v = 0.0f;\n if (mg < M) {\n int t=mg; int ow=t%WO; t/=WO; int oh=t%HO; int n=t/HO;\n int c=k/9; int kk=k-c*9; int r=kk/3; int s=kk-r*3;\n v = x[((n*8+c)*H + (oh+r))*W + (ow+s)];\n }\n sh[idx] = v;\n }\n __syncthreads();\n int mi = tid >> 2;\n int cg = tid & 3;\n int co0 = cg << 4;\n int mg = tile_m + mi;\n if (mg < M) {\n float a0=bias[co0+0], a1=bias[co0+1], a2=bias[co0+2], a3=bias[co0+3];\n float a4=bias[co0+4], a5=bias[co0+5], a6=bias[co0+6], a7=bias[co0+7];\n float a8=bias[co0+8], a9=bias[co0+9], a10=bias[co0+10], a11=bias[co0+11];\n float a12=bias[co0+12], a13=bias[co0+13], a14=bias[co0+14], a15=bias[co0+15];\n #pragma unroll\n for (int k=0; k<K; ++k) {\n float xv = sh[mi*K+k]; const float* wp = pw + k*CO + co0;\n a0=fmaf(xv,wp[0],a0); a1=fmaf(xv,wp[1],a1); a2=fmaf(xv,wp[2],a2); a3=fmaf(xv,wp[3],a3);\n a4=fmaf(xv,wp[4],a4); a5=fmaf(xv,wp[5],a5); a6=fmaf(xv,wp[6],a6); a7=fmaf(xv,wp[7],a7);\n a8=fmaf(xv,wp[8],a8); a9=fmaf(xv,wp[9],a9); a10=fmaf(xv,wp[10],a10); a11=fmaf(xv,wp[11],a11);\n a12=fmaf(xv,wp[12],a12); a13=fmaf(xv,wp[13],a13); a14=fmaf(xv,wp[14],a14); a15=fmaf(xv,wp[15],a15);\n }\n int t=mg; int ow=t%WO; t/=WO; int oh=t%HO; int n=t/HO;\n int base = ((n*HO+oh)*WO+ow)*CO + co0;\n float vals[16] = {a0,a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12,a13,a14,a15};\n #pragma unroll\n for (int i=0;i<16;++i) { float z=vals[i]; z = z>0.0f ? z : 0.0f; out[base+i] = (z>=3.0f) ? z : (z*(z+3.0f)*0.16666666666666666f); }\n }\n}\n\ntorch::Tensor conv_relu_hswish_forward(torch::Tensor x, torch::Tensor weight, torch::Tensor bias) {\n CHECK_CUDA(x); CHECK_CUDA(weight); CHECK_CUDA(bias); CHECK_CONTIGUOUS(x); CHECK_CONTIGUOUS(weight); CHECK_CONTIGUOUS(bias);\n auto opts=x.options();\n auto out=torch::empty_strided({128,64,126,126},{64*126*126,1,64*126,64},opts);\n auto packed=torch::empty({72,64},opts);\n cudaStream_t stream=at::cuda::getCurrentCUDAStream();\n pack_weight_kernel<<<18,256,0,stream>>>(weight.data_ptr<float>(), packed.data_ptr<float>());\n int blocks=(128*126*126 + 63)/64;\n conv_act_kernel64<<<blocks,256,0,stream>>>(x.data_ptr<float>(), packed.data_ptr<float>(), bias.data_ptr<float>(), out.data_ptr<float>());\n return out;\n}\n\"\"\"\n_ext=load_inline(name=\"conv_relu_hswish_ext_v3p\", cpp_sources=_cpp_src, cuda_sources=_cuda_src, functions=[\"conv_relu_hswish_forward\"], extra_cuda_cflags=[\"-O3\",\"--use_fast_math\"], verbose=False)\nclass ModelNew(nn.Module):\n def __init__(self,in_channels,out_channels,kernel_size):\n super(ModelNew,self).__init__(); self.conv=nn.Conv2d(in_channels,out_channels,kernel_size)\n def forward(self,x): return _ext.conv_relu_hswish_forward(x,self.conv.weight,self.conv.bias)\n" }
result ← profile_kernel (ok)
okprofile_kernel profile_kernel PASSED: profiling complete. === Kernel Profile Summary === --- Kernel Breakdown (by GPU time) --- #1: aten::empty_strided 6604.0μs (98%) calls=1 #2: aten::empty 124.0μs (2%) calls=1 --- Timing --- GPU time: 3268.03 μs --- Memory Bandwidth --- DRAM BW: 180.0/3350 GB/s (5.4%) read=27.0 write=153.0 GB/s Hit rates: L2=196.6% --- Compute Throughput --- Dominant pipe: FP32 util=12.1% Pipe util: FMA=12.1%, Tensor=0.3% --- Roofline Analysis --- Ridge point (FP32): 20.00 FLOPs/byte Classification: COMPUTE-BOUND --- Occupancy --- Achieved: 110.1% Eligible warps/cycle: 1.43 Launch: regs/thread=48, smem/blk=20480B, block=512, grid=31770 --- Memory Access Quality --- Global ld coalescing: 36.15 sectors/req (36.1x wasted BW) --- Warp Stall Reasons (% of issue cycles) --- long_scoreboard 4996.3% #################### short_scoreboard 1717.4% #################### mio_throttle 614.1% #################### --- Optimization Hints --- -> 4996% stalls: global memory latency (waiting for DRAM/L2). + sectors/req=36.1 -> uncoalesced global loads, restructure access pattern or use __ldg Try shared-memory tiling, prefetching, or reducing working set. -> Global load coalescing=36.1x (ideal=1.0) -> 36x wasted DRAM BW. Make per-warp accesses contiguous. -> Compute-bound but NOT using tensor cores. If applicable, use FP16/BF16 with torch.matmul or WMMA intrinsics.
turn 7 · 1 tool call(s) · 14.7s turn · 14.7s LLM · 6,855 chars (click to expand)
turn 714.7s turn · 14.7s LLM · 0.0s tools
reasoning
**Implementing improvements for warp coalescing** I’m exploring how to achieve better performance by using consecutive memory access for the warp with a fixed K value. This seems like a good start. I need to load from `sh[mi*K+k]` and set up a loop to iterate over `idx < K*BM`. Here, I'll assign `k` as `idx/BM` and `mi` as `idx%BM`. It looks like using `BM` with a power of 64 will help with coalescing efficiency. I'm thinking of moving ahead with version 4 of the implementation and considering `blockDim 256`.
call → profile_kernel
callprofile_kernel { "kernel_code": "import torch\nimport torch.nn as nn\nfrom torch.utils.cpp_extension import load_inline\n\n_cpp_src = r\"\"\"\n#include <torch/extension.h>\ntorch::Tensor conv_relu_hswish_forward(torch::Tensor x, torch::Tensor weight, torch::Tensor bias);\n\"\"\"\n_cuda_src = r\"\"\"\n#include <torch/extension.h>\n#include <ATen/cuda/CUDAContext.h>\n#include <cuda.h>\n#include <cuda_runtime.h>\n#define CHECK_CUDA(x) TORCH_CHECK(x.is_cuda(), #x \" must be a CUDA tensor\")\n#define CHECK_CONTIGUOUS(x) TORCH_CHECK(x.is_contiguous(), #x \" must be contiguous\")\n__global__ void pack_weight_kernel(const float* __restrict__ w, float* __restrict__ pw) { int idx=blockIdx.x*blockDim.x+threadIdx.x; if(idx<4608){int k=idx>>6; int co=idx&63; pw[idx]=w[co*72+k];}}\n__global__ void conv_act_kernel64(const float* __restrict__ x,const float* __restrict__ pw,const float* __restrict__ bias,float* __restrict__ out){\n constexpr int BM=64,K=72,CO=64,H=128,W=128,HO=126,WO=126,SP=15876,M=2032128; __shared__ float sh[BM*K]; int tile_m=blockIdx.x*BM; int tid=threadIdx.x;\n for(int idx=tid; idx<BM*K; idx+=blockDim.x){ int k=idx>>6; int mi=idx&63; int mg=tile_m+mi; float v=0.0f; if(mg<M){ int t=mg; int ow=t%WO; t/=WO; int oh=t%HO; int n=t/HO; int c=k/9; int kk=k-c*9; int r=kk/3; int s=kk-r*3; v=x[((n*8+c)*H+(oh+r))*W+(ow+s)]; } sh[mi*K+k]=v; }\n __syncthreads();\n int mi=tid>>2; int cg=tid&3; int co0=cg<<4; int mg=tile_m+mi; if(mg<M){\n float a0=bias[co0+0],a1=bias[co0+1],a2=bias[co0+2],a3=bias[co0+3],a4=bias[co0+4],a5=bias[co0+5],a6=bias[co0+6],a7=bias[co0+7];\n float a8=bias[co0+8],a9=bias[co0+9],a10=bias[co0+10],a11=bias[co0+11],a12=bias[co0+12],a13=bias[co0+13],a14=bias[co0+14],a15=bias[co0+15];\n #pragma unroll\n for(int k=0;k<K;++k){float xv=sh[mi*K+k]; const float* wp=pw+k*CO+co0; a0=fmaf(xv,wp[0],a0);a1=fmaf(xv,wp[1],a1);a2=fmaf(xv,wp[2],a2);a3=fmaf(xv,wp[3],a3);a4=fmaf(xv,wp[4],a4);a5=fmaf(xv,wp[5],a5);a6=fmaf(xv,wp[6],a6);a7=fmaf(xv,wp[7],a7);a8=fmaf(xv,wp[8],a8);a9=fmaf(xv,wp[9],a9);a10=fmaf(xv,wp[10],a10);a11=fmaf(xv,wp[11],a11);a12=fmaf(xv,wp[12],a12);a13=fmaf(xv,wp[13],a13);a14=fmaf(xv,wp[14],a14);a15=fmaf(xv,wp[15],a15);} \n int t=mg; int ow=t%WO; t/=WO; int oh=t%HO; int n=t/HO; int base=((n*HO+oh)*WO+ow)*CO+co0; float vals[16]={a0,a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12,a13,a14,a15};\n #pragma unroll\n for(int i=0;i<16;++i){float z=vals[i]; z=z>0.0f?z:0.0f; out[base+i]=(z>=3.0f)?z:(z*(z+3.0f)*0.16666666666666666f);} }}\ntorch::Tensor conv_relu_hswish_forward(torch::Tensor x,torch::Tensor weight,torch::Tensor bias){CHECK_CUDA(x);CHECK_CUDA(weight);CHECK_CUDA(bias);CHECK_CONTIGUOUS(x);CHECK_CONTIGUOUS(weight);CHECK_CONTIGUOUS(bias);auto opts=x.options();auto out=torch::empty_strided({128,64,126,126},{64*126*126,1,64*126,64},opts);auto packed=torch::empty({72,64},opts);cudaStream_t stream=at::cuda::getCurrentCUDAStream();pack_weight_kernel<<<18,256,0,stream>>>(weight.data_ptr<float>(),packed.data_ptr<float>());int blocks=(2032128+63)/64;conv_act_kernel64<<<blocks,256,0,stream>>>(x.data_ptr<float>(),packed.data_ptr<float>(),bias.data_ptr<float>(),out.data_ptr<float>());return out;}\n\"\"\"\n_ext=load_inline(name=\"conv_relu_hswish_ext_v4p\", cpp_sources=_cpp_src, cuda_sources=_cuda_src, functions=[\"conv_relu_hswish_forward\"], extra_cuda_cflags=[\"-O3\",\"--use_fast_math\"], verbose=False)\nclass ModelNew(nn.Module):\n def __init__(self,in_channels,out_channels,kernel_size): super(ModelNew,self).__init__(); self.conv=nn.Conv2d(in_channels,out_channels,kernel_size)\n def forward(self,x): return _ext.conv_relu_hswish_forward(x,self.conv.weight,self.conv.bias)\n" }
result ← profile_kernel (ok)
okprofile_kernel profile_kernel PASSED: profiling complete. === Kernel Profile Summary === --- Kernel Breakdown (by GPU time) --- #1: aten::empty_strided 2515.0μs (100%) calls=1 #2: aten::empty 12.0μs (0%) calls=1 --- Timing --- GPU time: 3206.43 μs [↓61.6μs ok] --- Memory Bandwidth --- DRAM BW: 183.8/3350 GB/s (5.5%) [↑0.1% ok] read=27.8 write=156.0 GB/s Hit rates: L2=196.2% --- Compute Throughput --- Dominant pipe: FP32 util=12.1% [↑0.0% ok] Pipe util: FMA=12.1%, Tensor=0.3% --- Roofline Analysis --- Ridge point (FP32): 20.00 FLOPs/byte Classification: COMPUTE-BOUND --- Occupancy --- Achieved: 110.0% [↓0.1% REGRESSED] Eligible warps/cycle: 1.47 Launch: regs/thread=48, smem/blk=20480B, block=512, grid=31770 --- Memory Access Quality --- Global ld coalescing: 36.01 sectors/req (36.0x wasted BW) --- Warp Stall Reasons (% of issue cycles) --- long_scoreboard 5720.9% #################### short_scoreboard 2486.7% #################### mio_throttle 620.2% #################### --- Optimization Hints --- -> 5721% stalls: global memory latency (waiting for DRAM/L2). + sectors/req=36.0 -> uncoalesced global loads, restructure access pattern or use __ldg Try shared-memory tiling, prefetching, or reducing working set. -> Global load coalescing=36.0x (ideal=1.0) -> 36x wasted DRAM BW. Make per-warp accesses contiguous. -> Compute-bound but NOT using tensor cores. If applicable, use FP16/BF16 with torch.matmul or WMMA intrinsics. --- Delta vs Previous Iteration --- GPU time: 3268.03→3206.43μs (↓61.60) ok DRAM BW%: 5.37→5.49% (↑0.11) ok Compute%: 12.13→12.14% (↑0.01) ok Occupancy: 110.10→109.99% (↓0.11) REGRESSED Eligible warps/cyc: 1.43→1.47 (↑0.04) ok Ld sectors/req: 36.15→36.01 (↓0.14) ok L2 hit%: 196.62→196.16% (↓0.47) REGRESSED
turn 814.6s turn · 14.6s LLM · 0.0s tools
reasoning
**Evaluating GPU processing efficiency** I’m analyzing the performance of the current setup. The GPU time is hovering around 3.2ms, which might not be enough for my needs. I should consider using cuDNN for improved speed because the reference implementation is faster. Perhaps I can focus on fusing activation kernels with torch conv to enhance performance. The custom kernel work is tricky, and I’m weighing whether a PyTorch reference would be acceptable if the custom CUDA replaces that compute pathway. Overall, I want optimal speed with acceptable methods. **Analyzing model speed and correctness** I need to compare processing speeds and correctness is a minor concern right now. It seems a custom CUDA solution may actually be faster than fully custom options. My model uses convolution in PyTorch, which complicates things. If I use `self.conv`, many submissions seem to operate under that assumption. I'm considering how to fuse the activation while ensuring I don't modify the convolution output inadvertently. By launching one kernel over the entire tensor after convolution, I’d aim for an effective speedup and enhanced performance. **Considering activation functions and speed** I’m looking at using ReLU versus hswish for my convolution outputs. The formula would look like this: for `z = conv`, I have `r = max(z, 0)`, followed by `y = r * clamp((r + 3) / 6, 0, 1)`. Since `r` is always non-negative, this approach seems straightforward. Using fast math should minimize errors and possibly be the fastest route. However, I'm aware that benchmarks—including reference with cuDNN plus activations—might show only modest speed improvements.
call → run_correctness
callrun_correctness { "kernel_code": "import torch\nimport torch.nn as nn\nfrom torch.utils.cpp_extension import load_inline\n_cpp_src=r\"\"\"\n#include <torch/extension.h>\ntorch::Tensor relu_hswish_inplace(torch::Tensor x);\n\"\"\"\n_cuda_src=r\"\"\"\n#include <torch/extension.h>\n#include <ATen/cuda/CUDAContext.h>\n#include <cuda.h>\n#include <cuda_runtime.h>\n__global__ void act_kernel(float* __restrict__ x, long n){\n long idx = blockIdx.x * blockDim.x + threadIdx.x;\n long stride = (long)blockDim.x * gridDim.x;\n for(long i=idx;i<n;i+=stride){\n float z=x[i];\n z = z > 0.0f ? z : 0.0f;\n float y = (z >= 3.0f) ? z : (z * (z + 3.0f) * 0.16666666666666666f);\n x[i]=y;\n }\n}\ntorch::Tensor relu_hswish_inplace(torch::Tensor x){\n TORCH_CHECK(x.is_cuda(), \"x must be CUDA\");\n TORCH_CHECK(x.scalar_type()==torch::kFloat32, \"x must be float\");\n long n=x.numel();\n int threads=256; int blocks=(int)((n+threads-1)/threads); if(blocks>65535) blocks=65535;\n cudaStream_t stream=at::cuda::getCurrentCUDAStream();\n act_kernel<<<blocks,threads,0,stream>>>(x.data_ptr<float>(), n);\n return x;\n}\n\"\"\"\n_ext=load_inline(name=\"fused_act_ext_v1\", cpp_sources=_cpp_src, cuda_sources=_cuda_src, functions=[\"relu_hswish_inplace\"], extra_cuda_cflags=[\"-O3\",\"--use_fast_math\"], verbose=False)\nclass ModelNew(nn.Module):\n def __init__(self,in_channels,out_channels,kernel_size):\n super(ModelNew,self).__init__(); self.conv=nn.Conv2d(in_channels,out_channels,kernel_size)\n def forward(self,x):\n y=self.conv(x)\n return _ext.relu_hswish_inplace(y)\n" }
result ← run_correctness (ok)
okrun_correctness run_correctness PASSED: (5 / 5) trials all matched the reference. Numerical precision: max_abs_err=1.19e-07 mean_abs_err=2.20e-09 max_rel_err=1.79e-07
turn 95.3s turn · 5.3s LLM · 0.0s tools
call → profile_kernel
callprofile_kernel { "kernel_code": "import torch\nimport torch.nn as nn\nfrom torch.utils.cpp_extension import load_inline\n_cpp_src=r\"\"\"\n#include <torch/extension.h>\ntorch::Tensor relu_hswish_inplace(torch::Tensor x);\n\"\"\"\n_cuda_src=r\"\"\"\n#include <torch/extension.h>\n#include <ATen/cuda/CUDAContext.h>\n#include <cuda.h>\n#include <cuda_runtime.h>\n__global__ void act_kernel(float* __restrict__ x, long n){\n long idx = blockIdx.x * blockDim.x + threadIdx.x;\n long stride = (long)blockDim.x * gridDim.x;\n for(long i=idx;i<n;i+=stride){\n float z=x[i];\n z = z > 0.0f ? z : 0.0f;\n float y = (z >= 3.0f) ? z : (z * (z + 3.0f) * 0.16666666666666666f);\n x[i]=y;\n }\n}\ntorch::Tensor relu_hswish_inplace(torch::Tensor x){\n TORCH_CHECK(x.is_cuda(), \"x must be CUDA\");\n TORCH_CHECK(x.scalar_type()==torch::kFloat32, \"x must be float\");\n long n=x.numel();\n int threads=256; int blocks=(int)((n+threads-1)/threads); if(blocks>65535) blocks=65535;\n cudaStream_t stream=at::cuda::getCurrentCUDAStream();\n act_kernel<<<blocks,threads,0,stream>>>(x.data_ptr<float>(), n);\n return x;\n}\n\"\"\"\n_ext=load_inline(name=\"fused_act_ext_v1p\", cpp_sources=_cpp_src, cuda_sources=_cuda_src, functions=[\"relu_hswish_inplace\"], extra_cuda_cflags=[\"-O3\",\"--use_fast_math\"], verbose=False)\nclass ModelNew(nn.Module):\n def __init__(self,in_channels,out_channels,kernel_size):\n super(ModelNew,self).__init__(); self.conv=nn.Conv2d(in_channels,out_channels,kernel_size)\n def forward(self,x):\n y=self.conv(x)\n return _ext.relu_hswish_inplace(y)\n" }
result ← profile_kernel (ok)
okprofile_kernel profile_kernel PASSED: profiling complete. === Kernel Profile Summary === --- Kernel Breakdown (by GPU time) --- #1: aten::conv2d 529275.0μs (25%) calls=1 #2: aten::convolution 529212.0μs (25%) calls=1 #3: aten::_convolution 529166.0μs (25%) calls=1 #4: aten::cudnn_convolution 515583.0μs (24%) calls=1 #5: aten::add_ 12741.0μs (1%) calls=1 ... +2 more kernels --- Timing --- GPU time: 1515.62 μs [↓1690.8μs ok] --- Memory Bandwidth --- DRAM BW: 5692.7/3350 GB/s (100.0%) [↑94.5% ok] read=2582.0 write=3110.7 GB/s Hit rates: L2=192.1% --- Compute Throughput --- Dominant pipe: FP32 util=74.8% [↑62.7% ok] Pipe util: FMA=74.8%, Tensor=3.7% --- Roofline Analysis --- Ridge point (FP32): 20.00 FLOPs/byte Classification: MEMORY-BOUND --- Occupancy --- Achieved: 186.5% [↑76.5% ok] Eligible warps/cycle: 2.83 Launch: regs/thread=295, smem/blk=36352B, block=512, grid=581505 --- Memory Access Quality --- Global ld coalescing: 11.21 sectors/req (11.2x wasted BW) --- Warp Stall Reasons (% of issue cycles) --- long_scoreboard 8423.5% #################### short_scoreboard 107.5% #################### mio_throttle 8.3% # --- Optimization Hints --- -> 8424% stalls: global memory latency (waiting for DRAM/L2). + sectors/req=11.2 -> uncoalesced global loads, restructure access pattern or use __ldg Try shared-memory tiling, prefetching, or reducing working set. -> Global load coalescing=11.2x (ideal=1.0) -> 11x wasted DRAM BW. Make per-warp accesses contiguous. --- Delta vs Previous Iteration --- GPU time: 3206.43→1515.62μs (↓1690.82) ok DRAM BW%: 5.49→100.00% (↑94.51) ok Compute%: 12.14→74.84% (↑62.70) ok Occupancy: 109.99→186.46% (↑76.47) ok Eligible warps/cyc: 1.47→2.83 (↑1.36) ok Ld sectors/req: 36.01→11.21 (↓24.80) ok L2 hit%: 196.16→192.13% (↓4.02) REGRESSED
turn 108.7s turn · 8.7s LLM · 0.0s tools
call → static_check
callstatic_check { "kernel_code": "import torch\nimport torch.nn as nn\nfrom torch.utils.cpp_extension import load_inline\n_cpp_src=r\"\"\"\n#include <torch/extension.h>\ntorch::Tensor relu_hswish_inplace(torch::Tensor x);\n\"\"\"\n_cuda_src=r\"\"\"\n#include <torch/extension.h>\n#include <ATen/cuda/CUDAContext.h>\n#include <cuda.h>\n#include <cuda_runtime.h>\n__global__ void act_kernel(float* __restrict__ x, long n){\n long idx = blockIdx.x * blockDim.x + threadIdx.x;\n long stride = (long)blockDim.x * gridDim.x;\n for(long i=idx;i<n;i+=stride){\n float z=x[i];\n z = z > 0.0f ? z : 0.0f;\n float y = (z >= 3.0f) ? z : (z * (z + 3.0f) * 0.16666666666666666f);\n x[i]=y;\n }\n}\ntorch::Tensor relu_hswish_inplace(torch::Tensor x){\n TORCH_CHECK(x.is_cuda(), \"x must be CUDA\");\n TORCH_CHECK(x.scalar_type()==torch::kFloat32, \"x must be float\");\n long n=x.numel();\n int threads=256; int blocks=(int)((n+threads-1)/threads); if(blocks>65535) blocks=65535;\n cudaStream_t stream=at::cuda::getCurrentCUDAStream();\n act_kernel<<<blocks,threads,0,stream>>>(x.data_ptr<float>(), n);\n return x;\n}\n\"\"\"\n_ext=load_inline(name=\"fused_act_ext_v1s\", cpp_sources=_cpp_src, cuda_sources=_cuda_src, functions=[\"relu_hswish_inplace\"], extra_cuda_cflags=[\"-O3\",\"--use_fast_math\"], verbose=False)\nclass ModelNew(nn.Module):\n def __init__(self,in_channels,out_channels,kernel_size):\n super(ModelNew,self).__init__(); self.conv=nn.Conv2d(in_channels,out_channels,kernel_size)\n def forward(self,x):\n y=self.conv(x)\n return _ext.relu_hswish_inplace(y)\n" }
result ← static_check (ok)
okstatic_check static_check PASSED: no violations or warnings detected.
turn 1110.3s turn · 10.3s LLM · 0.0s tools
call → run_correctness
callrun_correctness { "kernel_code": "import torch\nimport torch.nn as nn\nfrom torch.utils.cpp_extension import load_inline\n_cpp_src=r\"\"\"\n#include <torch/extension.h>\ntorch::Tensor relu_hswish_inplace(torch::Tensor x);\n\"\"\"\n_cuda_src=r\"\"\"\n#include <torch/extension.h>\n#include <ATen/cuda/CUDAContext.h>\n#include <cuda.h>\n#include <cuda_runtime.h>\n__device__ __forceinline__ float act(float z){ z = z > 0.0f ? z : 0.0f; return (z >= 3.0f) ? z : (z * (z + 3.0f) * 0.16666666666666666f); }\n__global__ void act4_kernel(float4* __restrict__ x4, long n4){\n long idx=blockIdx.x*blockDim.x+threadIdx.x; long stride=(long)blockDim.x*gridDim.x;\n for(long i=idx;i<n4;i+=stride){ float4 v=x4[i]; v.x=act(v.x); v.y=act(v.y); v.z=act(v.z); v.w=act(v.w); x4[i]=v; }\n}\n__global__ void act_kernel(float* __restrict__ x, long start, long n){\n long idx=start + blockIdx.x*blockDim.x+threadIdx.x; if(idx<n){ float z=x[idx]; x[idx]=act(z); }\n}\ntorch::Tensor relu_hswish_inplace(torch::Tensor x){\n TORCH_CHECK(x.is_cuda(), \"x must be CUDA\"); TORCH_CHECK(x.is_contiguous(), \"x must be contiguous\"); TORCH_CHECK(x.scalar_type()==torch::kFloat32, \"x must be float\");\n long n=x.numel(); long n4=n/4; int threads=256; int blocks=(int)((n4+threads-1)/threads); if(blocks>65535) blocks=65535; cudaStream_t stream=at::cuda::getCurrentCUDAStream();\n if(n4>0) act4_kernel<<<blocks,threads,0,stream>>>(reinterpret_cast<float4*>(x.data_ptr<float>()), n4);\n if((n&3)!=0) act_kernel<<<1,threads,0,stream>>>(x.data_ptr<float>(), n4*4, n);\n return x;\n}\n\"\"\"\n_ext=load_inline(name=\"fused_act_ext_v2\", cpp_sources=_cpp_src, cuda_sources=_cuda_src, functions=[\"relu_hswish_inplace\"], extra_cuda_cflags=[\"-O3\",\"--use_fast_math\"], verbose=False)\nclass ModelNew(nn.Module):\n def __init__(self,in_channels,out_channels,kernel_size): super(ModelNew,self).__init__(); self.conv=nn.Conv2d(in_channels,out_channels,kernel_size)\n def forward(self,x):\n y=self.conv(x)\n return _ext.relu_hswish_inplace(y)\n" }
result ← run_correctness (ok)
okrun_correctness run_correctness PASSED: (5 / 5) trials all matched the reference. Numerical precision: max_abs_err=1.19e-07 mean_abs_err=2.20e-09 max_rel_err=1.79e-07
turn 128.8s turn · 8.8s LLM · 0.0s tools · FINAL
call → submit_kernel
callsubmit_kernel { "kernel_code": "import torch\nimport torch.nn as nn\nfrom torch.utils.cpp_extension import load_inline\n\n_cpp_src = r\"\"\"\n#include <torch/extension.h>\ntorch::Tensor relu_hswish_inplace(torch::Tensor x);\n\"\"\"\n\n_cuda_src = r\"\"\"\n#include <torch/extension.h>\n#include <ATen/cuda/CUDAContext.h>\n#include <cuda.h>\n#include <cuda_runtime.h>\n\n__device__ __forceinline__ float fused_act(float z) {\n z = z > 0.0f ? z : 0.0f;\n return (z >= 3.0f) ? z : (z * (z + 3.0f) * 0.16666666666666666f);\n}\n\n__global__ void act4_kernel(float4* __restrict__ x4, long n4) {\n long idx = (long)blockIdx.x * blockDim.x + threadIdx.x;\n long stride = (long)blockDim.x * gridDim.x;\n for (long i = idx; i < n4; i += stride) {\n float4 v = x4[i];\n v.x = fused_act(v.x);\n v.y = fused_act(v.y);\n v.z = fused_act(v.z);\n v.w = fused_act(v.w);\n x4[i] = v;\n }\n}\n\n__global__ void act_tail_kernel(float* __restrict__ x, long start, long n) {\n long idx = start + (long)blockIdx.x * blockDim.x + threadIdx.x;\n if (idx < n) x[idx] = fused_act(x[idx]);\n}\n\ntorch::Tensor relu_hswish_inplace(torch::Tensor x) {\n TORCH_CHECK(x.is_cuda(), \"x must be CUDA\");\n TORCH_CHECK(x.is_contiguous(), \"x must be contiguous\");\n TORCH_CHECK(x.scalar_type() == torch::kFloat32, \"x must be float32\");\n long n = x.numel();\n long n4 = n >> 2;\n int threads = 256;\n int blocks = (int)((n4 + threads - 1) / threads);\n if (blocks > 65535) blocks = 65535;\n cudaStream_t stream = at::cuda::getCurrentCUDAStream();\n if (n4 > 0) {\n act4_kernel<<<blocks, threads, 0, stream>>>(reinterpret_cast<float4*>(x.data_ptr<float>()), n4);\n }\n if ((n & 3) != 0) {\n act_tail_kernel<<<1, threads, 0, stream>>>(x.data_ptr<float>(), n4 * 4, n);\n }\n return x;\n}\n\"\"\"\n\n_ext = load_inline(\n name=\"fused_relu_hswish_ext_final\",\n cpp_sources=_cpp_src,\n cuda_sources=_cuda_src,\n functions=[\"relu_hswish_inplace\"],\n extra_cuda_cflags=[\"-O3\", \"--use_fast_math\"],\n verbose=False,\n)\n\nclass ModelNew(nn.Module):\n def __init__(self, in_channels, out_channels, kernel_size):\n super(ModelNew, self).__init__()\n self.conv = nn.Conv2d(in_channels, out_channels, kernel_size)\n\n def forward(self, x):\n y = self.conv(x)\n return _ext.relu_hswish_inplace(y)\n" }
result ← submit_kernel (ok)
oksubmit_kernel submit_kernel PASSED: (5 / 5) correctness trials all passed. Kernel runtime: 1.52 μs Runtime stats: mean=1.52μs median=?μs std=0.67μs Numerical precision: max_abs_err=1.19e-07 mean_abs_err=2.20e-09 max_rel_err=1.79e-07 Memory: 593.16 MB peak (ref: 1585.41 MB, ratio: 0.3741x) Kernel launches: 7 (ref: 14, fusion ratio: 2.0) Energy: 726.06 mJ/run (ref: 484.22 mJ, ratio: 0.6669x) SOL score: 1.0
final submitted kernel (76 lines, 2,299 chars) — full source, untruncated
import torch
import torch.nn as nn
from torch.utils.cpp_extension import load_inline

_cpp_src = r"""
#include <torch/extension.h>
torch::Tensor relu_hswish_inplace(torch::Tensor x);
"""

_cuda_src = r"""
#include <torch/extension.h>
#include <ATen/cuda/CUDAContext.h>
#include <cuda.h>
#include <cuda_runtime.h>

__device__ __forceinline__ float fused_act(float z) {
    z = z > 0.0f ? z : 0.0f;
    return (z >= 3.0f) ? z : (z * (z + 3.0f) * 0.16666666666666666f);
}

__global__ void act4_kernel(float4* __restrict__ x4, long n4) {
    long idx = (long)blockIdx.x * blockDim.x + threadIdx.x;
    long stride = (long)blockDim.x * gridDim.x;
    for (long i = idx; i < n4; i += stride) {
        float4 v = x4[i];
        v.x = fused_act(v.x);
        v.y = fused_act(v.y);
        v.z = fused_act(v.z);
        v.w = fused_act(v.w);
        x4[i] = v;
    }
}

__global__ void act_tail_kernel(float* __restrict__ x, long start, long n) {
    long idx = start + (long)blockIdx.x * blockDim.x + threadIdx.x;
    if (idx < n) x[idx] = fused_act(x[idx]);
}

torch::Tensor relu_hswish_inplace(torch::Tensor x) {
    TORCH_CHECK(x.is_cuda(), "x must be CUDA");
    TORCH_CHECK(x.is_contiguous(), "x must be contiguous");
    TORCH_CHECK(x.scalar_type() == torch::kFloat32, "x must be float32");
    long n = x.numel();
    long n4 = n >> 2;
    int threads = 256;
    int blocks = (int)((n4 + threads - 1) / threads);
    if (blocks > 65535) blocks = 65535;
    cudaStream_t stream = at::cuda::getCurrentCUDAStream();
    if (n4 > 0) {
        act4_kernel<<<blocks, threads, 0, stream>>>(reinterpret_cast<float4*>(x.data_ptr<float>()), n4);
    }
    if ((n & 3) != 0) {
        act_tail_kernel<<<1, threads, 0, stream>>>(x.data_ptr<float>(), n4 * 4, n);
    }
    return x;
}
"""

_ext = load_inline(
    name="fused_relu_hswish_ext_final",
    cpp_sources=_cpp_src,
    cuda_sources=_cuda_src,
    functions=["relu_hswish_inplace"],
    extra_cuda_cflags=["-O3", "--use_fast_math"],
    verbose=False,
)

class ModelNew(nn.Module):
    def __init__(self, in_channels, out_channels, kernel_size):
        super(ModelNew, self).__init__()
        self.conv = nn.Conv2d(in_channels, out_channels, kernel_size)

    def forward(self, x):
        y = self.conv(x)
        return _ext.relu_hswish_inplace(y)