src/hotspot/share/runtime/objectMonitor.cpp

rev 51780 : imported patch syncknobs-00-base
rev 51781 : imported patch syncknobs-01-Knob_ReportSettings
rev 51782 : imported patch syncknobs-02-Knob_SpinBackOff
rev 51783 : imported patch syncknobs-03-BackOffMask
rev 51784 : imported patch syncknobs-04-Knob_ExitRelease
rev 51785 : imported patch syncknobs-05-Knob_InlineNotify
rev 51786 : imported patch syncknobs-06-Knob_Verbose
rev 51787 : imported patch syncknobs-07-Knob_VerifyInUse
rev 51788 : imported patch syncknobs-08-Knob_VerifyMatch
rev 51789 : imported patch syncknobs-09-Knob_SpinBase
rev 51790 : imported patch syncknobs-10-Knob_CASPenalty
rev 51791 : imported patch syncknobs-11-Knob_OXPenalty
rev 51792 : imported patch syncknobs-12-Knob_SpinSetSucc
rev 51793 : imported patch syncknobs-13-Knob_SpinEarly
rev 51794 : imported patch syncknobs-14-Knob_SuccEnabled
rev 51795 : imported patch syncknobs-15-Knob_SuccRestrict
rev 51796 : imported patch syncknobs-16-Knob_MaxSpinners
rev 51797 : imported patch syncknobs-17-Knob_SpinAfterFutile

*** 105,115 ****
  
  static int Knob_Bonus               = 100;     // spin success bonus
  static int Knob_BonusB              = 100;     // spin success bonus
  static int Knob_Penalty             = 200;     // spin failure penalty
  static int Knob_Poverty             = 1000;
- static int Knob_SpinAfterFutile     = 1;       // Spin after returning from park()
  static int Knob_FixedSpin           = 0;
  static int Knob_OState              = 3;       // Spinner checks thread state of _owner
  static int Knob_UsePause            = 1;
  static int Knob_ExitPolicy          = 0;
  static int Knob_PreSpin             = 10;      // 20-100 likely better
--- 105,114 ----
*** 565,575 ****
  
      // Assuming this is not a spurious wakeup we'll normally find _succ == Self.
      // We can defer clearing _succ until after the spin completes
      // TrySpin() must tolerate being called with _succ == Self.
      // Try yet another round of adaptive spinning.
!     if ((Knob_SpinAfterFutile & 1) && TrySpin(Self) > 0) break;
  
      // We can find that we were unpark()ed and redesignated _succ while
      // we were spinning.  That's harmless.  If we iterate and call park(),
      // park() will consume the event and return immediately and we'll
      // just spin again.  This pattern can repeat, leaving _succ to simply
--- 564,574 ----
  
      // Assuming this is not a spurious wakeup we'll normally find _succ == Self.
      // We can defer clearing _succ until after the spin completes
      // TrySpin() must tolerate being called with _succ == Self.
      // Try yet another round of adaptive spinning.
!     if (TrySpin(Self) > 0) break;
  
      // We can find that we were unpark()ed and redesignated _succ while
      // we were spinning.  That's harmless.  If we iterate and call park(),
      // park() will consume the event and return immediately and we'll
      // just spin again.  This pattern can repeat, leaving _succ to simply
*** 657,669 ****
  
  // ReenterI() is a specialized inline form of the latter half of the
  // contended slow-path from EnterI().  We use ReenterI() only for
  // monitor reentry in wait().
  //
! // In the future we should reconcile EnterI() and ReenterI(), adding
! // Knob_Reset and Knob_SpinAfterFutile support and restructuring the
! // loop accordingly.
  
  void ObjectMonitor::ReenterI(Thread * Self, ObjectWaiter * SelfNode) {
    assert(Self != NULL, "invariant");
    assert(SelfNode != NULL, "invariant");
    assert(SelfNode->_thread == Self, "invariant");
--- 656,666 ----
  
  // ReenterI() is a specialized inline form of the latter half of the
  // contended slow-path from EnterI().  We use ReenterI() only for
  // monitor reentry in wait().
  //
! // In the future we should reconcile EnterI() and ReenterI().
  
  void ObjectMonitor::ReenterI(Thread * Self, ObjectWaiter * SelfNode) {
    assert(Self != NULL, "invariant");
    assert(SelfNode != NULL, "invariant");
    assert(SelfNode->_thread == Self, "invariant");