Optimize Matmul_v2 (#37037)

Optimize dot product of Matmul_v2

Author: linjieccc

paddle/pten/kernels/functions/math/matmul_func.h

@@ -17,9 +17,7 @@ limitations under the License. */
 #include "paddle/fluid/operators/math/blas.h"
 #include "paddle/fluid/operators/math/complex_functors.h"
 
-#include "paddle/fluid/operators/eigen/eigen_function.h"
 #include "paddle/pten/core/dense_tensor.h"
-#include "paddle/pten/kernels/functions/eigen/common.h"
 
 namespace pten {
 namespace math {
@@ -105,34 +103,34 @@ void MatMulFunction(const DeviceContext& dev_ctx,
   const T* x_data = X.data<T>();
   const T* y_data = Y.data<T>();
 
+  auto blas = paddle::operators::math::GetBlas<DeviceContext, T>(dev_ctx);
+
   if (x_ndim == 1 && y_ndim == 1) {
+    const int M = X.numel();
+    const int N = Y.numel();
     PADDLE_ENFORCE_EQ(
-        X.numel(),
-        Y.numel(),
+        M,
+        N,
         paddle::platform::errors::InvalidArgument(
             "X's numbers must be equal to Y's numbers,"
             "when X/Y's dims =1. But received X has [%d] elements,"
             "received Y has [%d] elements",
-            X.numel(),
-            Y.numel()));
+            M,
+            N));
     VLOG(3) << "MatMul's case 1";
-    Out->Resize({1});
-    Out->mutable_data<T>();
-    auto out_eigen = EigenScalar<T>::From(*Out);
-    auto x_eigen = EigenVector<T>::Flatten(X);
-    auto y_eigen = EigenVector<T>::Flatten(Y);
-
-    auto& dev = *dev_ctx.eigen_device();
-    if (flag) {
-      out_eigen.device(dev) = (x_eigen * y_eigen).sum() + out_eigen;
-    } else {
-      out_eigen.device(dev) = (x_eigen * y_eigen).sum();
-    }
+    blas.GEMM(CblasNoTrans,
+              CblasTrans,
+              1,
+              1,
+              M,
+              static_cast<T>(1),
+              y_data,
+              x_data,
+              static_cast<T>(flag),
+              Out->mutable_data<T>());
     return;
   }
 
-  auto blas = paddle::operators::math::GetBlas<DeviceContext, T>(dev_ctx);
-
   if (x_ndim == 1) {
     const int N = X.numel();
     if (trans_y) {