--- old/src/hotspot/share/runtime/objectMonitor.cpp	2018-09-17 23:27:37.727749607 -0700
+++ new/src/hotspot/share/runtime/objectMonitor.cpp	2018-09-17 23:27:37.515749615 -0700
@@ -109,7 +109,6 @@
 int ObjectMonitor::Knob_SpinLimit    = 5000;    // derived by an external tool -
 
 static int Knob_SpinBase            = 0;       // Floor AKA SpinMin
-static int Knob_SpinBackOff         = 0;       // spin-loop backoff
 static int Knob_CASPenalty          = -1;      // Penalty for failed CAS
 static int Knob_OXPenalty           = -1;      // Penalty for observed _owner change
 static int Knob_SpinSetSucc         = 1;       // spinners set the _succ field
@@ -2215,8 +2214,7 @@
   // In the future consider doing this via os::init_2().
 
   if (os::is_MP()) {
-    BackOffMask = (1 << Knob_SpinBackOff) - 1;
-    // CONSIDER: BackOffMask = ROUNDUP_NEXT_POWER2 (ncpus-1)
+    BackOffMask = 0;
   } else {
     Knob_SpinLimit = 0;
     Knob_SpinBase  = 0;