diff --git a/src/allmydata/test/blocking.py b/src/allmydata/test/blocking.py
index ce7274106..6b6c05e5a 100644
--- a/src/allmydata/test/blocking.py
+++ b/src/allmydata/test/blocking.py
@@ -11,7 +11,7 @@ def print_stacks():
     current_thread = threading.get_ident()
     for thread_id, frame in sys._current_frames().items():
         if thread_id == current_thread:
-            traceback.print_stack(frame)
+            traceback.print_stack(frame, limit=10)
             break
 
 
@@ -26,8 +26,8 @@ def catch_blocking_in_event_loop(test=None):
 
     def cancel_and_rerun():
         signal.setitimer(signal.ITIMER_REAL, 0)
-        signal.setitimer(signal.ITIMER_REAL, 0.15)
-        current_scheduled[0] = reactor.callLater(0.1, cancel_and_rerun)
+        signal.setitimer(signal.ITIMER_REAL, 0.015)
+        current_scheduled[0] = reactor.callLater(0.01, cancel_and_rerun)
 
     cancel_and_rerun()