Optimize (legacy, reference-typed) VariableOp::Compute().

The `cinfo_` member can be initialized at construction time, so there is no need to acquire a mutex in the `Compute()` method.

The changes in "ops_testutil.cc" update the test harness to use a non-deprecated method for creating kernels in C++ tests. The deprecated API did not set the resource manager in `OpKernelConstruction`.

Note that this op is still rather inefficient because it looks up the variable in the `ResourceMgr` every time it is invoked (for backwards compatibility reasons, relating to state invalidation via `Session::Reset()`). However, new code—and all TF2 code—should use resource variables, which avoid this codepath.

PiperOrigin-RevId: 303410876
Change-Id: I29e114bb863fe8a1f483d4ce1e034f5f13f1a116

tensorflow/core/kernels/ops_testutil.cc

@@ -13,6 +13,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 ==============================================================================*/
 
+#include "tensorflow/core/framework/node_properties.h"
 #ifdef GOOGLE_CUDA
 #define EIGEN_USE_GPU
 #include "tensorflow/core/common_runtime/gpu/gpu_managed_allocator.h"
@@ -137,11 +138,16 @@ Status OpsTestBase::InitOp() {
 }
 
 Status OpsTestBase::InitOpWithGraphVersion(int graph_def_version) {
-  Status status;
-  kernel_ = CreateOpKernel(device_type_, device_, allocator(), node_def_,
-                           graph_def_version, &status);
-  if (kernel_ != nullptr) input_types_ = kernel_->input_types();
-  return status;
+  std::shared_ptr<const NodeProperties> props;
+  TF_RETURN_IF_ERROR(NodeProperties::CreateFromNodeDef(
+      node_def_, OpRegistry::Global(), &props));
+  OpKernel* kernel;
+  TF_RETURN_IF_ERROR(CreateOpKernel(
+      device_type_, device_, allocator(), /*flib=*/nullptr,
+      device_->resource_manager(), props, graph_def_version, &kernel));
+  kernel_.reset(kernel);
+  input_types_ = kernel_->input_types();
+  return Status::OK();
 }
 
 Status OpsTestBase::RunOpKernel() {

tensorflow/core/kernels/variable_ops.cc

@@ -50,15 +50,11 @@ class LegacyVar : public ResourceBase {
 VariableOp::VariableOp(OpKernelConstruction* context) : OpKernel(context) {
   OP_REQUIRES_OK(context, context->GetAttr("shape", &shape_));
   dtype_ = RemoveRefType(context->output_type(0));
+  OP_REQUIRES_OK(context, cinfo_.Init(context->resource_manager(), def(),
+                                      true /* use name() */));
 }
 
 void VariableOp::Compute(OpKernelContext* ctx) {
-  mutex_lock l(init_mu_);
-  if (!initialized_) {
-    OP_REQUIRES_OK(ctx, cinfo_.Init(ctx->resource_manager(), def(),
-                                    true /* use name() */));
-    initialized_ = true;
-  }
   auto creator = [this](LegacyVar** var) {
     *var = new LegacyVar(dtype_);
     (*var)->tensor()->set_shape(shape_);

tensorflow/core/kernels/variable_ops.h

@@ -36,10 +36,7 @@ class VariableOp : public OpKernel {
  private:
   DataType dtype_;
   TensorShape shape_;
-
-  mutex init_mu_;
-  ContainerInfo cinfo_ TF_GUARDED_BY(init_mu_);
-  bool initialized_ TF_GUARDED_BY(init_mu_){false};
+  ContainerInfo cinfo_;
 
   TF_DISALLOW_COPY_AND_ASSIGN(VariableOp);
 };