diff --git a/cpp/src/core/src/knowhere/index/vector_index/gpu_ivf.cpp b/cpp/src/core/src/knowhere/index/vector_index/gpu_ivf.cpp
index 01c4908511..c06c58c40c 100644
--- a/cpp/src/core/src/knowhere/index/vector_index/gpu_ivf.cpp
+++ b/cpp/src/core/src/knowhere/index/vector_index/gpu_ivf.cpp
@@ -123,6 +123,7 @@ void GPUIVF::search_impl(int64_t n,
                          int64_t *labels,
                          const Config &cfg) {
     if (auto device_index = std::static_pointer_cast<faiss::gpu::GpuIndexIVF>(index_)) {
+        // todo: allocate search memory
         auto nprobe = cfg.get_with_default("nprobe", size_t(1));
 
         std::lock_guard<std::mutex> lk(mutex_);
diff --git a/cpp/src/core/test/test_nsg/CMakeLists.txt b/cpp/src/core/test/test_nsg/CMakeLists.txt
index bd2db8072c..0ec275d9ee 100644
--- a/cpp/src/core/test/test_nsg/CMakeLists.txt
+++ b/cpp/src/core/test/test_nsg/CMakeLists.txt
@@ -27,6 +27,8 @@ aux_source_directory(${CMAKE_SOURCE_DIR}/src/knowhere/index/vector_index/nsg nsg
 set(interface_src
         ${CMAKE_SOURCE_DIR}/src/knowhere/index/vector_index/ivf.cpp
         ${CMAKE_SOURCE_DIR}/src/knowhere/index/vector_index/gpu_ivf.cpp
+        ${CMAKE_SOURCE_DIR}/src/knowhere/index/vector_index/cloner.cpp
+        ${CMAKE_SOURCE_DIR}/src/knowhere/index/vector_index/idmap.cpp
         ${CMAKE_SOURCE_DIR}/src/knowhere/index/vector_index/nsg_index.cpp
         ${CMAKE_SOURCE_DIR}/src/knowhere/adapter/structure.cpp
         ${CMAKE_SOURCE_DIR}/src/knowhere/common/exception.cpp