call InitDevices only once (#47678)

paddle/fluid/platform/init.cc

@@ -164,7 +164,10 @@ void LoadCustomDevice(const std::string &library_dir) {
 }
 #endif
 
+static std::once_flag init_devices_flag;
+
 void InitDevices() {
+  std::call_once(init_devices_flag, []() {
     // set name at the entry point of Paddle
     platform::SetCurrentThreadName("MainThread");
 // CUPTI attribute should be set before any CUDA context is created (see CUPTI
@@ -197,8 +200,8 @@ void InitDevices() {
       // use user specified XPUs in single-node multi-process mode.
       devices = platform::GetSelectedNPUDevices();
     } catch (const std::exception &exp) {
-    LOG(WARNING)
-        << "Compiled with PADDLE_WITH_ASCEND_CL, but no NPU found in runtime.";
+      LOG(WARNING) << "Compiled with PADDLE_WITH_ASCEND_CL, but no NPU found "
+                      "in runtime.";
     }
 #endif
 #ifdef PADDLE_WITH_IPU
@@ -219,6 +222,7 @@ void InitDevices() {
     }
 #endif
     InitDevices(devices);
+  });
 }
 
 void InitDevices(const std::vector<int> devices) {