diff --git a/libs/main/core/piobject.cpp b/libs/main/core/piobject.cpp
index 2297b449..95f345a1 100644
--- a/libs/main/core/piobject.cpp
+++ b/libs/main/core/piobject.cpp
@@ -839,7 +839,7 @@ PIObject::Deleter::Deleter() {
 	PRIVATE->thread.setSlot([this](){
 		PIVector<PIObject*> oq;
 		PRIVATE->thread.lock();
-		while(PRIVATE->obj_queue.isEmpty()) PRIVATE->cond_var.wait(PRIVATE->thread.mutex());
+		PRIVATE->cond_var.wait(PRIVATE->thread.mutex());
 		oq.swap(PRIVATE->obj_queue);
 		PRIVATE->thread.unlock();
 		for (PIObject * o : oq) deleteObject(o);
@@ -851,7 +851,9 @@ PIObject::Deleter::Deleter() {
 PIObject::Deleter::~Deleter() {
 	//piCout << "~Deleter ...";
 	PRIVATE->thread.stop();
+	PRIVATE->thread.mutex().lock();
 	PRIVATE->cond_var.notifyAll();
+	PRIVATE->thread.mutex().unlock();
 	PRIVATE->thread.waitForFinish();
 	for (PIObject * o : PRIVATE->obj_queue) deleteObject(o);
 	//piCout << "~Deleter ok";
diff --git a/libs/main/core/piwaitevent_p.cpp b/libs/main/core/piwaitevent_p.cpp
index 954aa870..72d85aee 100644
--- a/libs/main/core/piwaitevent_p.cpp
+++ b/libs/main/core/piwaitevent_p.cpp
@@ -95,6 +95,27 @@ bool PIWaitEvent::wait(int fd, CheckRole role) {
 }
 
 
+bool PIWaitEvent::sleep(int us) {
+	if (!isCreate()) return false;
+#ifdef WINDOWS
+	DWORD ret = WaitForSingleObjectEx(event, us / 1000, TRUE);
+	ResetEvent(event);
+	return ret == WAIT_TIMEOUT;
+#else
+	int nfds = pipe_fd[ReadEnd] + 1;
+	FD_ZERO(&(fds[CheckRead]));
+	FD_SET(pipe_fd[ReadEnd], &(fds[CheckRead]));
+	timeval timeout;
+	timeout.tv_sec  = us / 1000000;
+	timeout.tv_usec = us % 1000000;
+	int ret = ::select(nfds, &(fds[CheckRead]), nullptr, nullptr, &timeout);
+	int buf = 0;
+	while (::read(pipe_fd[ReadEnd], &buf, sizeof(buf)) > 0);
+	return ret == 0;
+#endif
+}
+
+
 void PIWaitEvent::interrupt() {
 	if (!isCreate()) return;
 #ifdef WINDOWS
diff --git a/libs/main/core/piwaitevent_p.h b/libs/main/core/piwaitevent_p.h
index a4395eaf..3dbdb137 100644
--- a/libs/main/core/piwaitevent_p.h
+++ b/libs/main/core/piwaitevent_p.h
@@ -31,7 +31,7 @@
 #endif
 
 
-class PIWaitEvent {
+class PIP_EXPORT PIWaitEvent {
 public:
 	~PIWaitEvent();
 
@@ -44,6 +44,7 @@ public:
 	void create();
 	void destroy();
 	bool wait(int fd = -1, CheckRole role = CheckRead);
+	bool sleep(int us); // return if sleep done
 	void interrupt();
 	bool isCreate() const;
 	void * getEvent() const; // WINDOWS only
diff --git a/libs/main/thread/pithread.cpp b/libs/main/thread/pithread.cpp
index 0276cd25..ee5d388f 100644
--- a/libs/main/thread/pithread.cpp
+++ b/libs/main/thread/pithread.cpp
@@ -485,7 +485,7 @@ void __PIThreadCollection::stoppedAuto() {
 	auto_mutex.lock();
 	auto_threads_.removeAll(t);
 	auto_mutex.unlock();
-	delete t;
+	t->deleteLater();
 }
 
 
diff --git a/libs/main/thread/pitimer.cpp b/libs/main/thread/pitimer.cpp
index 271fcddc..bd2758f6 100644
--- a/libs/main/thread/pitimer.cpp
+++ b/libs/main/thread/pitimer.cpp
@@ -19,6 +19,7 @@
 
 #include "pitimer.h"
 #include "piincludes_p.h"
+#include "piwaitevent_p.h"
 #ifdef PIP_TIMER_RT
 #  include <csignal>
 #endif
@@ -190,6 +191,7 @@ private:
 
 	PIThread thread_;
 	PISystemTime st_time, st_inc, st_wait, st_odt;
+	PIWaitEvent event;
 };
 
 
@@ -235,9 +237,10 @@ private:
 
 _PITimerImp_Thread::_PITimerImp_Thread() {
 	thread_.setName("__S__PITimerImp_Thread::thread");
-	wait_dt = 100;
-	wait_dd = 200;
-	wait_tick = 10;
+	wait_dt = 1000;
+	wait_dd = 2000;
+	wait_tick = 1000;
+	event.create();
 	//piCout << "_PITimerImp_Thread" << this << ", thread& =" << &thread_;
 	//piCout << "new _PITimerImp_Thread";
 }
@@ -245,6 +248,7 @@ _PITimerImp_Thread::_PITimerImp_Thread() {
 
 _PITimerImp_Thread::~_PITimerImp_Thread() {
 	stop(true);
+	event.destroy();
 }
 
 
@@ -275,6 +279,7 @@ bool _PITimerImp_Thread::startTimer(double interval_ms) {
 
 bool _PITimerImp_Thread::stopTimer(bool wait) {
 	thread_.stop();
+	event.interrupt();
 	if (wait) return thread_.waitForFinish();
 //	if (wait)
 //		if (!thread_.waitForFinish(10))
@@ -296,10 +301,12 @@ bool _PITimerImp_Thread::threadFunc() {
 			dwt = st_time - PISystemTime::current(true);
 		if (wth > 0) {
 			if (dwt.toMilliseconds() > wth + 1.) {
-				piMSleep(wth);
+				event.sleep(wth * 1000);
+				if (thread_.isStopping()) return false;
 				return false;
 			} else {
-				dwt.sleep();
+				event.sleep(dwt.toMicroseconds());
+				if (thread_.isStopping()) return false;
 				deferred_ = false;
 				st_time = PISystemTime::current(true);
 			}
@@ -319,10 +326,12 @@ bool _PITimerImp_Thread::threadFunc() {
 	if (wait_tick > 0) {
 		if (st_wait.toMilliseconds() > wait_tick + 1.) {
 			piMSleep(wait_tick);
+			if (thread_.isStopping()) return false;
 			return false;
 		} else {
 			//piCout << &thread_ << "sleep for" << st_wait;
-			st_wait.sleep();
+			event.sleep(st_wait.toMicroseconds());
+			if (thread_.isStopping()) return false;
 		}
 	} else {
 		if (st_wait.toMilliseconds() > 0.1)
diff --git a/main.cpp b/main.cpp
index 73e4ad68..5ace916b 100644
--- a/main.cpp
+++ b/main.cpp
@@ -3,6 +3,7 @@
 #include "pibytearray.h"
 #include "pimathbase.h"
 #include "pijson.h"
+#include "piwaitevent_p.h"
 
 using namespace PICoutManipulators;
 
@@ -88,6 +89,21 @@ void phase(const char * msg) {
 int main(int argc, char * argv[]) {
 	piCout << "main";
 
+	PITimer timer;
+	timer.setSlot([](){
+		static int cnt = 0;
+		piCout << "tick" << ++cnt;
+	});
+	timer.start(500);
+
+	piSleep(1.12);
+	piCout << "end";
+	PITimeMeasurer tm;
+	timer.stop();
+	double tm_ms = tm.elapsed_m();
+	piCout << "stop took" << tm_ms;
+	return 0;
+
 	/*for (int i = 0; i < count; ++i)
 		pipes[i].create();