diff --git a/libs/main/core/pitime.cpp b/libs/main/core/pitime.cpp
index 5e3fdb8c..3d041053 100644
--- a/libs/main/core/pitime.cpp
+++ b/libs/main/core/pitime.cpp
@@ -212,6 +212,13 @@ PIDateTime PIDateTime::current() {
 }
 
 
+void PISystemTime::toTimespec(void * ts) {
+#ifndef WINDOWS
+	t_cur->tv_sec = seconds;
+	t_cur->tv_nsec = nanoseconds;
+#endif
+}
+
 PISystemTime PISystemTime::abs() const {
 	if (seconds < 0)
 		return PISystemTime(piAbsl(seconds) - 1, 1000000000l - piAbsl(nanoseconds));
@@ -255,12 +262,12 @@ PISystemTime PISystemTime::current(bool precise_but_not_system) {
 	timeval tv;
 	tv.tv_sec = 0;
 	tv.tv_usec = 0;
-        gettimeofday(&tv, NULL);
+	gettimeofday(&tv, NULL);
 	t_cur.tv_sec = tv.tv_sec;
 	t_cur.tv_nsec = tv.tv_usec * 1000;
 #    else
 	timespec t_cur;
-	clock_gettime(0, &t_cur);
+	clock_gettime(precise_but_not_system ? CLOCK_MONOTONIC : 0, &t_cur);
 #    endif
 #  endif
 	return PISystemTime(t_cur.tv_sec, t_cur.tv_nsec);
diff --git a/libs/main/core/pitime.h b/libs/main/core/pitime.h
index e0a00c0b..90df73c7 100644
--- a/libs/main/core/pitime.h
+++ b/libs/main/core/pitime.h
@@ -93,6 +93,8 @@ public:
 	//! If you call this function on system time returned with \a PISystemTime::current() thread will be sleep almost forever.
 	void sleep() {piUSleep(piFloord(toMicroseconds()));} // wait self value, useful to wait some dT = (t1 - t0)
 	
+	//! On Unix system assign current value to timespec struct
+	void toTimespec(void *ts);
 	
 	//! Returns copy of this system time with absolutely values of s and ns
 	PISystemTime abs() const;
diff --git a/libs/main/thread/piconditionvar.cpp b/libs/main/thread/piconditionvar.cpp
index 9480bb79..a1092e13 100644
--- a/libs/main/thread/piconditionvar.cpp
+++ b/libs/main/thread/piconditionvar.cpp
@@ -86,37 +86,32 @@ void PIConditionVariable::wait(PIMutex& lk, const std::function<bool()>& conditi
 	}
 }
 
-void timespec_add_ms(timespec* ts, int ms) {
-    ts->tv_sec += ms / 1000;
-    ts->tv_nsec += ms % 1000 * 1000000;
-    if (ts->tv_nsec > 1000 * 1000 * 1000) {
-        ts->tv_sec++;
-        ts->tv_nsec -= 1000 * 1000 * 1000;
-    }
-}
 
 bool PIConditionVariable::waitFor(PIMutex &lk, int timeoutMs) {
 	bool isNotTimeout;
 #ifdef WINDOWS
 	isNotTimeout = SleepConditionVariableCS(&PRIVATE->nativeHandle, (PCRITICAL_SECTION)lk.handle(), timeoutMs) != 0;
 #else
-    timespec expire_ts;
-    clock_gettime(CLOCK_MONOTONIC, &expire_ts);
-    timespec_add_ms(&expire_ts, timeoutMs);
+	timespec expire_ts;
+	PISystemTime st = PISystemTime::current(true);
+	st.addMilliseconds(timeoutMs);
+	st.toTimespec(&expire_ts);
 	isNotTimeout = pthread_cond_timedwait(&PRIVATE->nativeHandle, (pthread_mutex_t*)lk.handle(), &expire_ts) == 0;
 #endif
 	if (PRIVATE->isDestroying) return false;
 	return isNotTimeout;
 }
 
+
 bool PIConditionVariable::waitFor(PIMutex& lk, int timeoutMs, const std::function<bool()> &condition) {
 	bool isCondition;
 #ifdef WINDOWS
 	PITimeMeasurer measurer;
 #else
 	timespec expire_ts;
-	clock_gettime(CLOCK_MONOTONIC, &expire_ts);
-    timespec_add_ms(&expire_ts, timeoutMs);
+	PISystemTime st = PISystemTime::current(true);
+	st.addMilliseconds(timeoutMs);
+	st.toTimespec(&expire_ts);
 #endif
 	while (true) {
 		isCondition = condition();