[Feature] : Add Deformable Conv2d TensorRT Plugin (#858)

* add dcn tensorrt plugin

* prepare for fp16 support

* fix for lint

* limit column buffer

* add docstring to memcpyPermute

mmcv/ops/csrc/deform_conv_cuda_kernel.cuh

@@ -66,11 +66,16 @@
 #ifndef DEFORM_CONV_CUDA_KERNEL_CUH
 #define DEFORM_CONV_CUDA_KERNEL_CUH
 
+#include <float.h>
+#ifdef MMCV_WITH_TRT
+#include "common_cuda_helper.hpp"
+#else  // MMCV_WITH_TRT
 #ifdef MMCV_USE_PARROTS
 #include "parrots_cuda_helper.hpp"
-#else
+#else  // MMCV_USE_PARROTS
 #include "pytorch_cuda_helper.hpp"
-#endif
+#endif  // MMCV_USE_PARROTS
+#endif  // MMCV_WITH_TRT
 
 template <typename T>
 __device__ T deformable_im2col_bilinear(const T *input, const int data_width,

mmcv/ops/csrc/tensorrt/plugins/trt_cuda_helper.cu

@@ -0,0 +1,66 @@
+#include "common_cuda_helper.hpp"
+#include "trt_cuda_helper.cuh"
+#include "trt_plugin_helper.hpp"
+
+using mmcv::TensorDesc;
+
+template <class scalar_t>
+__global__ void copy_permute_kernel(scalar_t *dst, const scalar_t *src, int n,
+                                    TensorDesc ts_src_stride,
+                                    TensorDesc ts_dst_stride,
+                                    TensorDesc ts_permute) {
+  const int src_dim = ts_src_stride.dim;
+  int *src_stride = &(ts_src_stride.stride[0]);
+  int *dst_stride = &(ts_dst_stride.stride[0]);
+  int *permute = &(ts_permute.shape[0]);
+  CUDA_1D_KERNEL_LOOP(index, n) {
+    size_t dst_index = index;
+    size_t src_index = 0;
+    for (int i = 0; i < src_dim; ++i) {
+      int dim_index = dst_index / dst_stride[i];
+      dst_index = dst_index % dst_stride[i];
+      src_index += dim_index * src_stride[permute[i]];
+    }
+    dst[index] = src[src_index];
+  }
+}
+
+template <class scalar_t>
+void memcpyPermute(scalar_t *dst, const scalar_t *src, int *src_size,
+                   int *permute, int src_dim, cudaStream_t stream) {
+  size_t copy_size = 1;
+  TensorDesc ts_permute;
+  memcpy(&(ts_permute.shape[0]), permute, src_dim * sizeof(int));
+
+  TensorDesc ts_src_stride;
+  TensorDesc ts_dst_stride;
+  ts_src_stride.dim = src_dim;
+  ts_dst_stride.dim = src_dim;
+  int *src_stride = &(ts_src_stride.stride[0]);
+  int *dst_stride = &(ts_dst_stride.stride[0]);
+  int *dst_size = &(ts_dst_stride.shape[0]);
+  src_stride[src_dim - 1] = 1;
+  dst_stride[src_dim - 1] = 1;
+
+  for (int i = src_dim - 1; i >= 0; --i) {
+    dst_size[i] = src_size[permute[i]];
+    if (i < src_dim - 1) {
+      src_stride[i] = src_stride[i + 1] * src_size[i + 1];
+    }
+  }
+
+  for (int i = src_dim - 1; i >= 0; --i) {
+    copy_size *= dst_size[i];
+    if (i < src_dim - 1) {
+      dst_stride[i] = dst_stride[i + 1] * dst_size[i + 1];
+    }
+  }
+
+  copy_permute_kernel<scalar_t>
+      <<<GET_BLOCKS(copy_size), THREADS_PER_BLOCK, 0, stream>>>(
+          dst, src, copy_size, ts_src_stride, ts_dst_stride, ts_permute);
+}
+
+template void memcpyPermute<float>(float *dst, const float *src, int *src_size,
+                                   int *permute, int src_dim,
+                                   cudaStream_t stream);