Fix virtualenv issue in object detection notebook; Fix Windows build error for absl::GetCurrentTimeNanos() (#334)

* Add virtualenv step to isolate yolov4 model conversion

* Fix Windows build error for absl::GetCurrentTimeNanos()

* Revert metadata changes in object detection notebook

Author: sspintel

examples/notebooks/OpenVINO_TensorFlow_object_detection_example.ipynb

@@ -194,7 +194,9 @@
     "else:\n",
     "    path = \"{0}/openvino_tensorflow/examples/\".format(OVTF_DIR)\n",
     "%cd {path}\n",
-    "!chmod +x convert_yolov4.sh && bash convert_yolov4.sh\n",
+    "!python3 -m pip install virtualenv\n",
+    "!virtualenv env\n",
+    "!source env/bin/activate && chmod +x convert_yolov4.sh && bash convert_yolov4.sh && deactivate\n",
     "# Once the model conversion is completed; move back to outside of examples directory\n",
     "%cd ../"
    ]

openvino_tensorflow/kernels/encapsulate_op.cc

@@ -44,6 +44,12 @@
   EXPAND(m(__VA_ARGS__))  // L1431 op_kernel.h
 #endif
 
+#ifdef _WIN32
+#define GetCurrentTimeNanos() profiler::GetCurrentTimeNanos()
+#else
+#define GetCurrentTimeNanos() absl::GetCurrentTimeNanos()
+#endif
+
 using namespace std;
 
 namespace tensorflow {
@@ -211,9 +217,9 @@ void NGraphEncapsulateOp::Compute(OpKernelContext* ctx) {
   if (api::IsRewritePassEnabled() &&
       s_tf_timing_run_enabled_map[m_cluster_id]) {
     // Measure the timing of cluster through force TF run
-    int64_t start_ns = absl::GetCurrentTimeNanos();
+    int64_t start_ns = GetCurrentTimeNanos();
     OP_REQUIRES_OK(ctx, Fallback(ctx));
-    int64_t duration_in_ms = (absl::GetCurrentTimeNanos() - start_ns) / 1e6;
+    int64_t duration_in_ms = (GetCurrentTimeNanos() - start_ns) / 1e6;
     OVTF_VLOG(1) << "Iter: " << m_iter;
     OVTF_VLOG(1) << "TF: Cluster " << m_cluster_id << " took " << duration_in_ms
                  << " ms.";
@@ -409,9 +415,9 @@ void NGraphEncapsulateOp::Compute(OpKernelContext* ctx) {
       OVTF_VLOG(4) << "NGraphEncapsulateOp::Compute call starting for cluster "
                    << m_cluster_id;
       try {
-        int64_t start_ns = absl::GetCurrentTimeNanos();
+        int64_t start_ns = GetCurrentTimeNanos();
         ng_exec->Call(ng_inputs, ng_func_outputs, multi_req_execution);
-        int64_t duration_in_ms = (absl::GetCurrentTimeNanos() - start_ns) / 1e6;
+        int64_t duration_in_ms = (GetCurrentTimeNanos() - start_ns) / 1e6;
         OVTF_VLOG(1) << "Iter: " << m_iter;
         OVTF_VLOG(1) << "OVTF: Cluster " << m_cluster_id << " took "
                      << duration_in_ms << " ms.";