Use thread yield primitive for busy waits

core/os/thread.h

@@ -116,6 +116,8 @@ class Thread {
 
 	_FORCE_INLINE_ static bool is_main_thread() { return caller_id == MAIN_ID; } // Gain a tiny bit of perf here because there is no need to validate caller_id here, because only main thread will be set as 1.
 
+	_FORCE_INLINE_ static void yield() { std::this_thread::yield(); }
+
 	static Error set_name(const String &p_name);
 
 	ID start(Thread::Callback p_callback, void *p_user, const Settings &p_settings = Settings());
@@ -176,6 +178,8 @@ class Thread {
 
 	_FORCE_INLINE_ static bool is_main_thread() { return true; }
 
+	_FORCE_INLINE_ static void yield() {}
+
 	static Error set_name(const String &p_name) { return ERR_UNAVAILABLE; }
 
 	void start(Thread::Callback p_callback, void *p_user, const Settings &p_settings = Settings()) {}

editor/editor_file_system.cpp

@@ -3018,7 +3018,7 @@ void EditorFileSystem::reimport_files(const Vector<String> &p_files) {
 							current_index = tdata.max_index.get();
 							ep->step(reimport_files[current_index].path.get_file(), current_index, false);
 						}
-						OS::get_singleton()->delay_usec(1);
+						Thread::yield();
 					} while (!WorkerThreadPool::get_singleton()->is_group_task_completed(group_task));
 
 					WorkerThreadPool::get_singleton()->wait_for_group_task_completion(group_task);

editor/editor_log.cpp

@@ -395,7 +395,7 @@ void EditorLog::_add_log_line(LogMessage &p_message, bool p_replace_previous) {
 		// Force sync last line update (skip if number of unprocessed log messages is too large to avoid editor lag).
 		if (log->get_pending_paragraphs() < 100) {
 			while (!log->is_finished()) {
-				::OS::get_singleton()->delay_usec(1);
+				Thread::yield();
 			}
 		}
 	}

editor/editor_node.cpp

@@ -5454,7 +5454,7 @@ bool EditorNode::immediate_confirmation_dialog(const String &p_text, const Strin
 	cd->popup_centered();
 
 	while (true) {
-		OS::get_singleton()->delay_usec(1);
+		Thread::yield();
 		DisplayServer::get_singleton()->process_events();
 		Main::iteration();
 		if (singleton->immediate_dialog_confirmed || !cd->is_visible()) {

modules/gltf/editor/editor_scene_importer_blend.cpp

@@ -577,7 +577,7 @@ bool EditorFileSystemImportFormatSupportQueryBlend::query() {
 	confirmed = false;
 
 	while (true) {
-		OS::get_singleton()->delay_usec(1);
+		Thread::yield();
 		DisplayServer::get_singleton()->process_events();
 		Main::iteration();
 		if (!configure_blender_dialog->is_visible() || confirmed) {

scene/main/http_request.cpp

@@ -175,7 +175,7 @@ void HTTPRequest::_thread_func(void *p_userdata) {
 			if (exit) {
 				break;
 			}
-			OS::get_singleton()->delay_usec(1);
+			Thread::yield();
 		}
 	}
 

tests/core/threads/test_worker_thread_pool.h

@@ -116,7 +116,7 @@ static void static_test_daemon(void *p_arg) {
 
 static void static_busy_task(void *p_arg) {
 	while (!exit.is_set()) {
-		OS::get_singleton()->delay_usec(1);
+		Thread::yield();
 	}
 }
 
@@ -150,7 +150,7 @@ TEST_CASE("[WorkerThreadPool] Run a yielding daemon as the only hope for other t
 	}
 
 	while (counter[1].get() != legit_tasks_count) {
-		OS::get_singleton()->delay_usec(1);
+		Thread::yield();
 	}
 
 	exit.set();