diff --git a/Lib/threading.py b/Lib/threading.py

index 7ab9ad8..dcedd3b 100644

--- a/Lib/threading.py

+++ b/Lib/threading.py

@@ -3,7 +3,7 @@

 import sys as _sys

 import _thread

-from time import monotonic as _time

+from time import monotonic as _time, sleep as _sleep

 from traceback import format_exc as _format_exc

 from _weakrefset import WeakSet

 from itertools import islice as _islice, count as _count

@@ -296,7 +296,25 @@ class Condition:

                 gotit = True

             else:

                 if timeout > 0:

-                    gotit = waiter.acquire(True, timeout)

+                    # rhbz#2003758: Avoid waiter.acquire(True, timeout) since

+                    # it uses the system clock internally.

+                    #

+                    # Balancing act:  We can't afford a pure busy loop, so we

+                    # have to sleep; but if we sleep the whole timeout time,

+                    # we'll be unresponsive.  The scheme here sleeps very

+                    # little at first, longer as time goes on, but never longer

+                    # than 20 times per second (or the timeout time remaining).

+                    endtime = _time() + timeout

+                    delay = 0.0005 # 500 us -> initial delay of 1 ms

+                    while True:

+                        gotit = waiter.acquire(0)

+                        if gotit:

+                            break

+                        remaining = min(endtime - _time(), timeout)

+                        if remaining <= 0:

+                            break

+                        delay = min(delay * 2, remaining, .05)

+                        _sleep(delay)

                 else:

                     gotit = waiter.acquire(False)

             return gotit