Move reduceSum to elementwise_op_function.h (#9773)

* add cuda_device_functions.h

* move reduceSum to elementwise_op_function.h

Author: chengduo

paddle/fluid/operators/elementwise_op_function.h

@@ -13,14 +13,15 @@ See the License for the specific language governing permissions and
 limitations under the License. */
 
 #pragma once
+#include <algorithm>
 #include "paddle/fluid/framework/eigen.h"
 #include "paddle/fluid/framework/op_registry.h"
 #include "paddle/fluid/framework/operator.h"
 #include "paddle/fluid/platform/transform.h"
 
 #ifdef __NVCC__
+#include <cuda.h>
 #include <thrust/iterator/iterator_adaptor.h>
-#include "paddle/fluid/platform/cuda_helper.h"
 constexpr int ELEMWISE_MAX_BLOCK_DIM = 1024;
 #endif
 
@@ -43,35 +44,35 @@ namespace operators {
  */
 inline void get_mid_dims(const framework::DDim& x_dims,
                          const framework::DDim& y_dims, const int axis,
-                         int& pre, int& n, int& post) {
-  pre = 1;
-  n = 1;
-  post = 1;
+                         int* pre, int* n, int* post) {
+  *pre = 1;
+  *n = 1;
+  *post = 1;
   for (int i = 0; i < axis; ++i) {
-    pre *= x_dims[i];
+    (*pre) *= x_dims[i];
   }
 
   for (int i = 0; i < y_dims.size(); ++i) {
     PADDLE_ENFORCE_EQ(x_dims[i + axis], y_dims[i],
                       "Broadcast dimension mismatch.");
-    n *= y_dims[i];
+    (*n) *= y_dims[i];
   }
 
   for (int i = axis + y_dims.size(); i < x_dims.size(); ++i) {
-    post *= x_dims[i];
+    (*post) *= x_dims[i];
   }
 }
 
-inline void trim_trailing_singular_dims(framework::DDim& dims) {
+inline void trim_trailing_singular_dims(framework::DDim* dims) {
   // Remove trailing dimensions of size 1 for y
-  auto actual_dims_size = dims.size();
+  auto actual_dims_size = dims->size();
   for (; actual_dims_size != 0; --actual_dims_size) {
-    if (dims[actual_dims_size - 1] != 1) break;
+    if ((*dims)[actual_dims_size - 1] != 1) break;
   }
-  if (actual_dims_size != dims.size()) {
-    auto actual_dims = framework::vectorize(dims);
+  if (actual_dims_size != dims->size()) {
+    auto actual_dims = framework::vectorize(*dims);
     actual_dims.resize(actual_dims_size);
-    dims = framework::make_ddim(actual_dims);
+    *dims = framework::make_ddim(actual_dims);
   }
 }
 
@@ -159,7 +160,7 @@ class RowwiseTransformIterator<T, platform::CUDADeviceContext>
       RowwiseTransformIterator<T, platform::CUDADeviceContext>, const T*>
       super_t;
   HOSTDEVICE RowwiseTransformIterator(const T* x, int n)
-      : super_t(x), begin_(x), n_(n){};
+      : super_t(x), begin_(x), n_(n) {}
   friend class thrust::iterator_core_access;
 
  private:
@@ -179,7 +180,7 @@ class MidWiseTransformIterator<T, platform::CUDADeviceContext>
       MidWiseTransformIterator<T, platform::CUDADeviceContext>, const T*>
       super_t;
   HOSTDEVICE MidWiseTransformIterator(const T* x, int n, int post)
-      : super_t(x), begin_(x), n_(n), post_(post){};
+      : super_t(x), begin_(x), n_(n), post_(post) {}
   friend class thrust::iterator_core_access;
 
  private:
@@ -333,6 +334,55 @@ static void ElemwiseGradBroadcast1CPU(const T* x, const T* y, const T* out,
   }
 }
 #ifdef __NVCC__
+
+// __shfl_down has been deprecated as of CUDA 9.0.
+#if CUDA_VERSION < 9000
+template <typename T>
+__forceinline__ __device__ T __shfl_down_sync(unsigned, T val, int delta) {
+  return __shfl_down(val, delta);
+}
+#define CREATE_SHFL_MASK(mask, predicate) mask = 0u;
+#else
+#define FULL_WARP_MASK 0xFFFFFFFF
+#define CREATE_SHFL_MASK(mask, predicate) \
+  mask = __ballot_sync(FULL_WARP_MASK, (predicate))
+#endif
+
+template <typename T>
+__device__ T reduceSum(T val, int tid, int len) {
+  // TODO(zcd): The warp size should be taken from the
+  // parameters of the GPU but not specified as 32 simply.
+  // To make the reduceSum more efficiently,
+  // I use Warp-Level Parallelism and assume the Warp size
+  // is 32 which may be different for different GPU,
+  // but most card's warp size is 32.
+  __shared__ T shm[32];
+  const int warpSize = 32;
+  unsigned mask = 0u;
+  CREATE_SHFL_MASK(mask, tid < len);
+
+  for (int offset = warpSize / 2; offset > 0; offset /= 2)
+    val += __shfl_down_sync(mask, val, offset);
+
+  if (tid < warpSize) shm[tid] = 0;
+
+  __syncthreads();
+
+  if (tid % warpSize == 0) {
+    shm[tid / warpSize] = val;
+  }
+
+  CREATE_SHFL_MASK(mask, tid < warpSize);
+
+  if (tid < warpSize) {
+    val = shm[tid];
+    for (int offset = warpSize / 2; offset > 0; offset /= 2)
+      val += __shfl_down_sync(mask, val, offset);
+  }
+
+  return val;
+}
+
 template <typename T, typename DX_OP, typename DY_OP>
 static __global__ void ElemwiseGradBroadcast1CUDAKernel(
     const T* x, const T* y, const T* out, const T* dout, int h, int w,
@@ -355,7 +405,7 @@ static __global__ void ElemwiseGradBroadcast1CUDAKernel(
 
   if (dy) {
     h = h > ELEMWISE_MAX_BLOCK_DIM ? ELEMWISE_MAX_BLOCK_DIM : h;
-    val = platform::reduceSum(val, tid, h);
+    val = reduceSum(val, tid, h);
     if (threadIdx.x == 0) {
       dy[j] = val;
     }
@@ -432,7 +482,7 @@ static __global__ void ElemwiseGradBroadcast2CUDAKernel(
   if (dy) {
     int h = pre * post;
     h = h > ELEMWISE_MAX_BLOCK_DIM ? ELEMWISE_MAX_BLOCK_DIM : h;
-    val = platform::reduceSum(val, tid, h);
+    val = reduceSum(val, tid, h);
     if (threadIdx.x == 0) {
       dy[j] = val;
     }
@@ -472,11 +522,11 @@ void ElemwiseGradCompute(const framework::ExecutionContext& ctx,
     auto y_dim = y.dims();
 
     axis = (axis == -1 ? x_dim.size() - y_dim.size() : axis);
-    trim_trailing_singular_dims(y_dim);
+    trim_trailing_singular_dims(&y_dim);
     axis = (y_dim.size() == 0) ? x_dim.size() : axis;
 
     int pre, n, post;
-    get_mid_dims(x_dim, y_dim, axis, pre, n, post);
+    get_mid_dims(x_dim, y_dim, axis, &pre, &n, &post);
     if (post == 1) {
       int h = pre;
       int w = n;
@@ -514,7 +564,7 @@ void ElemwiseGradCompute(const framework::ExecutionContext& ctx,
       }
     }
   }
-};
+}
 
 template <typename DeviceContext, typename T, typename functor,
           typename broadcastfunctor, typename broadcast2functor>
@@ -543,11 +593,11 @@ void ElementwiseGradCompute(const framework::ExecutionContext& ctx,
   }
 
   axis = (axis == -1 ? x_dims.size() - y_dims.size() : axis);
-  trim_trailing_singular_dims(y_dims);
+  trim_trailing_singular_dims(&y_dims);
   axis = (y_dims.size() == 0) ? x_dims.size() : axis;
 
   int pre, n, post;
-  get_mid_dims(x_dims, y_dims, axis, pre, n, post);
+  get_mid_dims(x_dims, y_dims, axis, &pre, &n, &post);
 
   if (post == 1) {
     broadcastfunctor f;
@@ -582,11 +632,11 @@ void ElementwiseComputeEx(const framework::ExecutionContext& ctx,
   axis = (axis == -1 ? x_dims.size() - y_dims.size() : axis);
   PADDLE_ENFORCE(axis >= 0 && axis < x_dims.size(),
                  "Axis should be in range [0, x_dims)");
-  trim_trailing_singular_dims(y_dims);
+  trim_trailing_singular_dims(&y_dims);
   axis = (y_dims.size() == 0) ? x_dims.size() : axis;
 
   int pre, n, post;
-  get_mid_dims(x_dims, y_dims, axis, pre, n, post);
+  get_mid_dims(x_dims, y_dims, axis, &pre, &n, &post);
   if (post == 1) {
     functor.RunRowWise(n, pre);
     return;

paddle/fluid/platform/cuda_helper.h

@@ -62,53 +62,5 @@ CUDA_ATOMIC_WRAPPER(Add, double) {
 }
 #endif
 
-// __shfl_down has been deprecated as of CUDA 9.0.
-#if CUDA_VERSION < 9000
-template <typename T>
-__forceinline__ __device__ T __shfl_down_sync(unsigned, T val, int delta) {
-  return __shfl_down(val, delta);
-}
-#define CREATE_SHFL_MASK(mask, predicate) mask = 0u;
-#else
-#define FULL_WARP_MASK 0xFFFFFFFF
-#define CREATE_SHFL_MASK(mask, predicate) \
-  mask = __ballot_sync(FULL_WARP_MASK, (predicate))
-#endif
-
-template <typename T>
-__device__ T reduceSum(T val, int tid, int len) {
-  // TODO(zcd): The warp size should be taken from the
-  // parameters of the GPU but not specified as 32 simply.
-  // To make the reduceSum more efficiently,
-  // I use Warp-Level Parallelism and assume the Warp size
-  // is 32 which may be different for different GPU,
-  // but most card's warp size is 32.
-  __shared__ T shm[32];
-  const int warpSize = 32;
-  unsigned mask = 0u;
-  CREATE_SHFL_MASK(mask, tid < len);
-
-  for (int offset = warpSize / 2; offset > 0; offset /= 2)
-    val += __shfl_down_sync(mask, val, offset);
-
-  if (tid < warpSize) shm[tid] = 0;
-
-  __syncthreads();
-
-  if (tid % warpSize == 0) {
-    shm[tid / warpSize] = val;
-  }
-
-  CREATE_SHFL_MASK(mask, tid < warpSize);
-
-  if (tid < warpSize) {
-    val = shm[tid];
-    for (int offset = warpSize / 2; offset > 0; offset /= 2)
-      val += __shfl_down_sync(mask, val, offset);
-  }
-
-  return val;
-}
-
 }  // namespace platform
 }  // namespace paddle