[X86] Optimize gru and softmax (#2877)

* Optimize softmax. When the input tensor is 2-D and axis is 1, there is no need to resize.

* Optimize the gru, avoid calling Tensor::Slice.
test=develop

* Remove a std::vector in softmax.
test=develop

* Define CalculateSeqWidth to get the width of a sequence.
test=develop

lite/backends/x86/jit/more/mkl/mkl.h

@@ -142,14 +142,13 @@ void StrideScal(const T* a, const T* x, T* y, int n, int stride);
 // remain is the product of dimension shapes after the axis dimension
 template <typename T>
 void Softmax(const T* x, T* y, int n, int bs, int remain = 1) {
-  std::vector<T> entities(bs);
   for (int i = 0; i < bs; ++i) {
-    entities[i] = x[i * n];
+    T entity = x[i * n];
     for (int c = 1; c < n; ++c) {
-      entities[i] = x[i * n + c] > entities[i] ? x[i * n + c] : entities[i];
+      entity = x[i * n + c] > entity ? x[i * n + c] : entity;
     }
     for (int c = 0; c < n; ++c) {
-      y[i * n + c] = x[i * n + c] - entities[i];
+      y[i * n + c] = x[i * n + c] - entity;
     }
   }
   VExp(y, y, n * bs);

lite/backends/x86/math/math_function.cc

@@ -110,11 +110,7 @@ void set_constant(const lite::Context<Target>& context,
                   lite::Tensor* tensor,
                   float value) {
   TensorSetConstantWithTarget<Target> func(context, tensor, value);
-  // #ifdef PADDLE_WITH_CUDA
-  // tensor->target().apply_visitor(func);
-  // #else
   func();
-  // #endif
 }
 
 template <typename T>
@@ -123,7 +119,7 @@ struct RowwiseAdd<lite::TargetType::kX86, T> {
                   const lite::Tensor& input,
                   const lite::Tensor& vector,
                   lite::Tensor* output) {
-    auto in_dims = input.dims();
+    const auto& in_dims = input.dims();
     auto size = input.numel() / in_dims[0];
     PADDLE_ENFORCE_EQ(vector.numel(), size);
     PADDLE_ENFORCE_EQ(output->dims(), in_dims);

lite/kernels/x86/gru_compute.h

@@ -48,6 +48,10 @@ inline void ReorderInitState(const lite::Context<TARGET(kX86)>& context,
   row_shuffle(context, src, index_lod, dst, indexed_src);
 }
 
+static inline int64_t CalculateSeqWidth(const DDim& dims) {
+  return dims.count(1, dims.size());
+}
+
 template <typename T>
 class GRUCompute : public KernelLite<TARGET(kX86), PRECISION(kFloat)> {
  public:
@@ -65,15 +69,16 @@ class GRUCompute : public KernelLite<TARGET(kX86), PRECISION(kFloat)> {
     auto* bias = param.bias;
 
     auto* batch_gate = param.batch_gate;
-    batch_gate->mutable_data<T>();
     auto* batch_reset_hidden_prev = param.batch_reset_hidden_prev;
-    batch_reset_hidden_prev->mutable_data<T>();
     auto* batch_hidden = param.batch_hidden;
-    batch_hidden->mutable_data<T>();
+    T* batch_gate_ptr = batch_gate->mutable_data<T>();
+    T* batch_reset_hidden_prev_ptr = batch_reset_hidden_prev->mutable_data<T>();
+    T* batch_hidden_ptr = batch_hidden->mutable_data<T>();
+
     auto* hidden = param.hidden;
     hidden->mutable_data<T>();
 
-    auto hidden_dims = hidden->dims();
+    const auto& hidden_dims = hidden->dims();
 
     lite::x86::math::LoDTensor2BatchFunctor<TARGET(kX86), T> to_batch;
     to_batch(context, *input, batch_gate, true, is_reverse);
@@ -90,19 +95,23 @@ class GRUCompute : public KernelLite<TARGET(kX86), PRECISION(kFloat)> {
         const_cast<T*>(weight_data + 2 * frame_size * frame_size);
     Tensor ordered_h0;
 
-    std::vector<size_t> order(batch_gate->lod()[2]);
-
     if (h0) {
       // Since the batch computing for GRU reorders the input sequences
       // according to their length. The initialized cell state also needs
       // to reorder.
+      const std::vector<size_t>& order(batch_gate->lod()[2]);
       ReorderInitState<T>(context, *h0, order, &ordered_h0, true);
       gru_value.prev_out_value = ordered_h0.mutable_data<T>();
     } else {
       gru_value.prev_out_value = nullptr;
     }
-    auto batch_starts = batch_gate->lod()[0];
+
+    const auto& batch_starts = batch_gate->lod()[0];
     size_t seq_len = batch_starts.size() - 1;
+    int64_t batch_gate_width = CalculateSeqWidth(batch_gate->dims());
+    int64_t batch_reset_hidden_prev_width =
+        CalculateSeqWidth(batch_reset_hidden_prev->dims());
+    int64_t batch_hidden_width = CalculateSeqWidth(batch_hidden->dims());
     auto active_node =
         lite::x86::math::detail::GetActivationType(param.activation);
     auto active_gate =
@@ -145,13 +154,10 @@ class GRUCompute : public KernelLite<TARGET(kX86), PRECISION(kFloat)> {
         int64_t bend = static_cast<int64_t>(batch_starts[n + 1]);
         int64_t cur_batch_size = bend - bstart;
 
-        Tensor gate_t = batch_gate->Slice<T>(bstart, bend);
-        Tensor reset_hidden_prev_t =
-            batch_reset_hidden_prev->Slice<T>(bstart, bend);
-        Tensor hidden_t = batch_hidden->Slice<T>(bstart, bend);
-        gru_value.output_value = hidden_t.mutable_data<T>();
-        gru_value.gate_value = gate_t.mutable_data<T>();
-        gru_value.reset_output_value = reset_hidden_prev_t.mutable_data<T>();
+        gru_value.output_value = batch_hidden_ptr + bstart * batch_hidden_width;
+        gru_value.gate_value = batch_gate_ptr + bstart * batch_gate_width;
+        gru_value.reset_output_value = batch_reset_hidden_prev_ptr +
+                                       bstart * batch_reset_hidden_prev_width;
 
         if (gru_value.prev_out_value) {
           blas.GEMM_COMPUTE(CblasNoTrans,
@@ -188,13 +194,10 @@ class GRUCompute : public KernelLite<TARGET(kX86), PRECISION(kFloat)> {
         int64_t bend = static_cast<int64_t>(batch_starts[n + 1]);
         int64_t cur_batch_size = bend - bstart;
 
-        Tensor gate_t = batch_gate->Slice<T>(bstart, bend);
-        Tensor reset_hidden_prev_t =
-            batch_reset_hidden_prev->Slice<T>(bstart, bend);
-        Tensor hidden_t = batch_hidden->Slice<T>(bstart, bend);
-        gru_value.output_value = hidden_t.mutable_data<T>();
-        gru_value.gate_value = gate_t.mutable_data<T>();
-        gru_value.reset_output_value = reset_hidden_prev_t.mutable_data<T>();
+        gru_value.output_value = batch_hidden_ptr + bstart * batch_hidden_width;
+        gru_value.gate_value = batch_gate_ptr + bstart * batch_gate_width;
+        gru_value.reset_output_value = batch_reset_hidden_prev_ptr +
+                                       bstart * batch_reset_hidden_prev_width;
 
         lite::x86::math::GRUUnitFunctor<TARGET(kX86), T>::compute(
             context,

lite/kernels/x86/softmax_compute.h

@@ -55,24 +55,33 @@ class SoftmaxCompute : public KernelLite<TARGET(kX86), PRECISION(kFloat)> {
     auto& context = ctx_->As<X86Context>();
     CHECK(param.output);
     CHECK(param.x);
-    param.output->mutable_data<T>();
-    const int rank = param.x->dims().size();
+
+    auto* x = param.x;
+    auto* output = param.output;
+    output->mutable_data<T>();
+
+    const int rank = x->dims().size();
     const int axis = CanonicalAxis(param.axis, rank);
-    int axis_dim = param.x->dims()[axis];
-    const int n = SizeToAxis(axis, param.x->dims());
-    const int d = SizeFromAxis(axis, param.x->dims());
+    int axis_dim = x->dims()[axis];
+    if (rank == 2 && axis == 1) {
+      lite::x86::math::SoftmaxFunctor<lite::TargetType::kX86, T, true>()(
+          context, axis_dim, x, output);
+    } else {
+      const int n = SizeToAxis(axis, x->dims());
+      const int d = SizeFromAxis(axis, x->dims());
 
-    DDim shape(std::vector<DDim::value_type>{n, d});
+      DDim x_dims = x->dims();
+      DDim out_dims = output->dims();
 
-    Tensor input_2d;
-    Tensor out_2d;
-    input_2d.ShareDataWith(*param.x);
-    input_2d.Resize(shape);
-    out_2d.ShareDataWith(*param.output);
-    out_2d.Resize(shape);
+      DDim shape_2d(std::vector<DDim::value_type>{n, d});
+      x->Resize(shape_2d);
+      output->Resize(shape_2d);
 
-    lite::x86::math::SoftmaxFunctor<lite::TargetType::kX86, T, true>()(
-        context, axis_dim, &input_2d, &out_2d);
+      lite::x86::math::SoftmaxFunctor<lite::TargetType::kX86, T, true>()(
+          context, axis_dim, x, output);
+      x->Resize(x_dims);
+      output->Resize(out_dims);
+    }
   }
 
   virtual ~SoftmaxCompute() = default;