fix opencv launch too many threads

mindspore/ccsrc/minddata/dataset/engine/execution_tree.cc

@@ -134,6 +134,20 @@ void ExecutionTree::PrintNode(std::ostream &out, const std::shared_ptr<DatasetOp
 
 // Start the execution of the tree
 Status ExecutionTree::Launch() {
+  // opencv limit too many threads
+#ifndef ENABLE_ANDROID
+#if !defined(_WIN32) && !defined(_WIN64)
+  int32_t thread_num = get_nprocs();
+  if (thread_num == 0) {
+    std::string err_msg = "Invalid thread number.";
+    RETURN_STATUS_UNEXPECTED(err_msg);
+  }
+  if (thread_num > 8)
+    cv::setNumThreads(8);
+  else
+    cv::setNumThreads(thread_num);
+#endif
+#endif
   // Tree must be built and prepared before it can be launched!
   if (tree_state_ != kDeTStateReady) {
     std::string err_msg =

mindspore/ccsrc/minddata/dataset/engine/execution_tree.h

@@ -21,6 +21,12 @@
 #include <stack>
 #include <string>
 #include <vector>
+#ifndef ENABLE_ANDROID
+#if !defined(_WIN32) && !defined(_WIN64)
+#include <sys/sysinfo.h>
+#include <opencv2/imgproc/imgproc.hpp>
+#endif
+#endif
 #include "minddata/dataset/engine/datasetops/dataset_op.h"
 #include "minddata/dataset/util/status.h"
 #include "mindspore/ccsrc/minddata/dataset/engine/perf/profiling.h"

mindspore/ccsrc/minddata/dataset/kernels/image/image_utils.cc

@@ -97,8 +97,6 @@ Status Resize(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tensor> *out
   if (input_cv->Rank() != 3 && input_cv->Rank() != 2) {
     RETURN_STATUS_UNEXPECTED("Input Tensor is not in shape of <H,W,C> or <H,W>");
   }
-  // OpenCv lanuch too many threads.
-  cv::setNumThreads(8);
   cv::Mat in_image = input_cv->mat();
   // resize image too large or too small
   if (output_height == 0 || output_height > in_image.rows * 1000 || output_width == 0 ||