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

*** 101,111 ****
  // The knob* variables are effectively final.  Once set they should
  // never be modified hence.  Consider using __read_mostly with GCC.
  
  int ObjectMonitor::Knob_SpinLimit    = 5000;    // derived by an external tool -
  
- 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
  static int Knob_SpinEarly           = 1;
  static int Knob_SuccEnabled         = 1;       // futile wake throttling
  static int Knob_SuccRestrict        = 0;       // Limit successors + spinners to at-most-one
--- 101,110 ----
*** 1863,1873 ****
  
    // We're good to spin ... spin ingress.
    // CONSIDER: use Prefetch::write() to avoid RTS->RTO upgrades
    // when preparing to LD...CAS _owner, etc and the CAS is likely
    // to succeed.
-   int caspty  = Knob_CASPenalty;
    int oxpty   = Knob_OXPenalty;
    int sss     = Knob_SpinSetSucc;
    if (sss && _succ == NULL) _succ = Self;
    Thread * prv = NULL;
  
--- 1862,1871 ----
*** 1931,1949 ****
          }
          return 1;
        }
  
        // The CAS failed ... we can take any of the following actions:
!       // * penalize: ctr -= Knob_CASPenalty
        // * exit spin with prejudice -- goto Abort;
        // * exit spin without prejudice.
        // * Since CAS is high-latency, retry again immediately.
        prv = ox;
!       if (caspty == -2) break;
!       if (caspty == -1) goto Abort;
!       ctr -= caspty;
!       continue;
      }
  
      // Did lock ownership change hands ?
      if (ox != prv && prv != NULL) {
        if (oxpty == -2) break;
--- 1929,1944 ----
          }
          return 1;
        }
  
        // The CAS failed ... we can take any of the following actions:
!       // * penalize: ctr -= CASPenalty
        // * exit spin with prejudice -- goto Abort;
        // * exit spin without prejudice.
        // * Since CAS is high-latency, retry again immediately.
        prv = ox;
!       goto Abort;
      }
  
      // Did lock ownership change hands ?
      if (ox != prv && prv != NULL) {
        if (oxpty == -2) break;