diff -r 7494f3972726 Makefile.pre.in
--- a/Makefile.pre.in	Tue Feb 03 15:12:13 2015 +0100
+++ b/Makefile.pre.in	Mon Feb 09 23:15:07 2015 +0100
@@ -838,7 +838,7 @@ Objects/setobject.o: $(srcdir)/Objects/s
 $(OPCODETARGETS_H): $(OPCODETARGETGEN_FILES)
 	$(OPCODETARGETGEN) $(OPCODETARGETS_H)
 
-Python/ceval.o: $(OPCODETARGETS_H) $(srcdir)/Python/ceval_gil.h
+Python/ceval.o: $(OPCODETARGETS_H) $(srcdir)/Python/ceval_gil.h $(srcdir)/Python/condvar.h
 
 Python/frozen.o: Python/importlib.h
 
@@ -1626,7 +1626,7 @@ patchcheck:
 
 # Dependencies
 
-Python/thread.o: @THREADHEADERS@
+Python/thread.o: @THREADHEADERS@ $(srcdir)/Python/condvar.h
 
 # Declare targets that aren't real files
 .PHONY: all build_all sharedmods oldsharedmods test quicktest
diff -r 7494f3972726 Python/condvar.h
--- a/Python/condvar.h	Tue Feb 03 15:12:13 2015 +0100
+++ b/Python/condvar.h	Mon Feb 09 23:15:07 2015 +0100
@@ -59,20 +59,6 @@
 
 #include <pthread.h>
 
-#define PyCOND_ADD_MICROSECONDS(tv, interval) \
-do { /* TODO: add overflow and truncation checks */ \
-    tv.tv_usec += (long) interval; \
-    tv.tv_sec += tv.tv_usec / 1000000; \
-    tv.tv_usec %= 1000000; \
-} while (0)
-
-/* We assume all modern POSIX systems have gettimeofday() */
-#ifdef GETTIMEOFDAY_NO_TZ
-#define PyCOND_GETTIMEOFDAY(ptv) gettimeofday(ptv)
-#else
-#define PyCOND_GETTIMEOFDAY(ptv) gettimeofday(ptv, (struct timezone *)NULL)
-#endif
-
 /* The following functions return 0 on success, nonzero on error */
 #define PyMUTEX_T pthread_mutex_t
 #define PyMUTEX_INIT(mut)       pthread_mutex_init((mut), NULL)
@@ -81,22 +67,50 @@ do { /* TODO: add overflow and truncatio
 #define PyMUTEX_UNLOCK(mut)     pthread_mutex_unlock(mut)
 
 #define PyCOND_T pthread_cond_t
-#define PyCOND_INIT(cond)       pthread_cond_init((cond), NULL)
 #define PyCOND_FINI(cond)       pthread_cond_destroy(cond)
 #define PyCOND_SIGNAL(cond)     pthread_cond_signal(cond)
 #define PyCOND_BROADCAST(cond)  pthread_cond_broadcast(cond)
 #define PyCOND_WAIT(cond, mut)  pthread_cond_wait((cond), (mut))
 
+#define MONOTONIC
+
+Py_LOCAL_INLINE(int)
+PyCOND_INIT(PyCOND_T *cond)
+{
+    pthread_condattr_t attr;
+    int err;
+
+    (void)pthread_condattr_init(&attr);
+#ifdef MONOTONIC
+    err = pthread_condattr_setclock(&attr, CLOCK_MONOTONIC);
+    if (err)
+        return err;
+#endif
+    err = pthread_cond_init(cond, &attr);
+    (void)pthread_condattr_destroy(&attr);
+    return err;
+}
+
 /* return 0 for success, 1 on timeout, -1 on error */
 Py_LOCAL_INLINE(int)
 PyCOND_TIMEDWAIT(PyCOND_T *cond, PyMUTEX_T *mut, PY_LONG_LONG us)
 {
     int r;
     struct timespec ts;
-    struct timeval deadline;
+    _PyTime_timeval deadline;
 
-    PyCOND_GETTIMEOFDAY(&deadline);
-    PyCOND_ADD_MICROSECONDS(deadline, us);
+#ifdef MONOTONIC
+    _PyTime_monotonic(&deadline);
+#else
+    _PyTime_gettimeofday(&deadline);
+#endif
+
+    /* TODO: add overflow and truncation checks */
+    assert(us <= LONG_MAX);
+    deadline.tv_usec += (long)us;
+    deadline.tv_sec += deadline.tv_usec / 1000000;
+    deadline.tv_usec %= 1000000;
+
     ts.tv_sec = deadline.tv_sec;
     ts.tv_nsec = deadline.tv_usec * 1000;
 
diff -r 7494f3972726 Python/thread_pthread.h
--- a/Python/thread_pthread.h	Tue Feb 03 15:12:13 2015 +0100
+++ b/Python/thread_pthread.h	Mon Feb 09 23:15:07 2015 +0100
@@ -84,6 +84,7 @@
      defined(HAVE_SEM_TIMEDWAIT))
 #  define USE_SEMAPHORES
 #else
+#  define MONOTONIC
 #  undef USE_SEMAPHORES
 #endif
 
@@ -99,18 +100,16 @@
 #  define SET_THREAD_SIGMASK sigprocmask
 #endif
 
-
-/* We assume all modern POSIX systems have gettimeofday() */
-#ifdef GETTIMEOFDAY_NO_TZ
-#define GETTIMEOFDAY(ptv) gettimeofday(ptv)
+#ifdef MONOTONIC
+#define GETTIME(ptv) _PyTime_monotonic(ptv)
 #else
-#define GETTIMEOFDAY(ptv) gettimeofday(ptv, (struct timezone *)NULL)
+#define GETTIME(ptv) _PyTime_gettimeofday(ptv)
 #endif
 
 #define MICROSECONDS_TO_TIMESPEC(microseconds, ts) \
 do { \
-    struct timeval tv; \
-    GETTIMEOFDAY(&tv); \
+    _PyTime_timeval tv; \
+    GETTIME(&tv); \
     tv.tv_usec += microseconds % 1000000; \
     tv.tv_sec += microseconds / 1000000; \
     tv.tv_sec += tv.tv_usec / 1000000; \
@@ -405,6 +404,7 @@ PyThread_allocate_lock(void)
 {
     pthread_lock *lock;
     int status, error = 0;
+    pthread_condattr_t attr;
 
     dprintf(("PyThread_allocate_lock called\n"));
     if (!initialized)
@@ -425,9 +425,14 @@ PyThread_allocate_lock(void)
            will cause errors. */
         _Py_ANNOTATE_PURE_HAPPENS_BEFORE_MUTEX(&lock->mut);
 
-        status = pthread_cond_init(&lock->lock_released,
-                                   pthread_condattr_default);
+        pthread_condattr_init(&attr);
+#ifdef MONOTONIC
+        status = pthread_condattr_setclock(&attr, CLOCK_MONOTONIC);
+        CHECK_STATUS("pthread_condattr_setclock");
+#endif
+        status = pthread_cond_init(&lock->lock_released, &attr);
         CHECK_STATUS("pthread_cond_init");
+        pthread_condattr_destroy(&attr);
 
         if (error) {
             PyMem_RawFree((void *)lock);