try to fix distributed unit-test

test=develop

paddle/fluid/framework/operator.cc

@@ -919,8 +919,6 @@ std::vector<KernelConfig>* OperatorWithKernel::GetKernelConfig(
 void OperatorWithKernel::RunImpl(const Scope& scope,
                                  const platform::Place& place) const {
   const Scope* cur_scope = &scope;
-  if (!runtime_ctx_ || pre_scope_ != cur_scope ||
-      scope.FindVar(details::kLocalExecScopeName)) {
   // RuntimeContext is used to relate input/output names of Operator with
   // the corresponding variables in Scope.
   // In a same Scope, since the input/output names of Operator do not change
@@ -928,6 +926,9 @@ void OperatorWithKernel::RunImpl(const Scope& scope,
   // iteration of the execution to save the elapsed time.
   // Note that the Scope should not be the local scope, since local scope
   // would be cleaned regularly.
+  if (scope.FindVar(details::kLocalExecScopeName)) {
+    runtime_ctx_.reset(new RuntimeContext(Inputs(), Outputs(), scope));
+  } else if (!runtime_ctx_ || pre_scope_ != cur_scope) {
     runtime_ctx_.reset(new RuntimeContext(Inputs(), Outputs(), scope));
     pre_scope_ = cur_scope;
   }

paddle/fluid/framework/scope.cc

@@ -107,6 +107,10 @@ const Scope* Scope::FindScope(const Variable* var) const {
   return FindScopeInternal(var);
 }
 
+bool Scope::HasLocalVar(const std::string& name) const {
+  return vars_.find(name) != vars_.end();
+}
+
 void Scope::DropKids() {
   SCOPE_KIDS_WRITER_LOCK
   for (Scope* s : kids_) delete s;

paddle/fluid/framework/scope.h

@@ -75,6 +75,10 @@ class Scope {
   /// Caller doesn't own the returned Variable.
   Variable* FindLocalVar(const std::string& name) const;
 
+  /// Find whether a variable in the current scope.
+  /// Return false if cannot find.
+  bool HasLocalVar(const std::string& name) const;
+
   const Scope* parent() const { return parent_; }
 
   /// Find the scope or an ancestor scope that contains the given variable.