Make CUDA a NHWC EP (#17200)
### Description
CUDA inference speed heavily relies on Tensor Cores. To have tensor
cores achieve the optimal throughput they require the data layout to be
NHWC rather than NCHW.
### Motivation and Context
Especially for convolutional networks this is very important. I will
illustrate this using a very simple network:
```
import torch
import torch.nn as nn
class Net1(nn.Module):
def __init__(self):
super(Net1, self).__init__()
# 1 input image channel, 6 output channels, 5x5 square convolution
# kernel
self.m = nn.ModuleList([
nn.Conv2d(in_channels=8, out_channels=32, kernel_size=5, stride=1),
nn.Conv2d(in_channels=32, out_channels=64, kernel_size=3, stride=1),
nn.Conv2d(in_channels=64, out_channels=128, kernel_size=3, stride=1),
nn.Conv2d(in_channels=128, out_channels=128, kernel_size=3, stride=1, bias=False),
nn.Conv2d(in_channels=128, out_channels=128, kernel_size=3, stride=1, bias=False),
])
def forward(self, x):
for module in self.m:
x = module(x)
return x
if __name__ == "__main__":
dtype = torch.half
device = "cuda"
dummy_input = torch.randn(8, 8, 512, 512, dtype=dtype, device=device)
model = Net1().to(dtype=dtype, device=device)
input_names = ["input1"]
output_names = ["output1"]
torch.onnx.export(model, dummy_input, "test.onnx",
input_names=input_names, output_names=output_names)
```
I profiled the launch of `./build/RelWithDebInfo/onnxruntime_perf_test
-e cuda -I -q -t 5 test.onnx` using sys and nvtx ranges.
Current master launches below kernels:
If I add the introduced `-l` flag we see below kernels:
Notice the missing NCHW<>NHWC kernels per operation. The layout
optimizer introduced a transpose op as first and last op of the whole
network. The `op_generic_tensor_kernel` shows the bias used which should
also be optimized out next.
Measured across some very basic models:
| CUDA EP | **NCHW** [ms] | **NHWC** [ms] | Speedup |
|:------------------------|--------------------------------------:|-----------------------------------------:|------------------:|
| | -e cuda -t 5 -q | -e cuda -t 5 -q -l | |
| resnet101-v2-7_bs8_fp16 | 18.33 | 13.07 | 1.4 |
| resnet101-v2-7_bs8 | 21.8 | 12.06 | 1.81 |
| test | 102.07 | 73.62 | 1.39 |
Average speedup: 1.53
## Outlook
Next the mission will be to first write a templated unit test to check
for correctness of NHWC vs NCHW ops. After that we have to transition
more ops to measure perf improvements on a broader range of models.
Currently this is not easily possible as we can do not support all ops
in the NHWC domain.
---------
Co-authored-by: Tianlei Wu <tlwu@microsoft.com>
