diff --git a/C/absmi.c b/C/absmi.c
index b01fd1728..478a90875 100755
--- a/C/absmi.c
+++ b/C/absmi.c
@@ -1094,7 +1094,7 @@ Yap_absmi(int inp)
 	/* HEY, leave indexing block alone!! */
 	/* check if we are the ones using this code */
 #if defined(YAPOR) || defined(THREADS)
-	LOCK(ap->PELock);
+	PELOCK(1, ap);
 	PP = ap;
 	DEC_CLREF_COUNT(cl);
 	/* clear the entry from the trail */
@@ -1395,7 +1395,7 @@ Yap_absmi(int inp)
 	/* HEY, leave indexing block alone!! */
 	/* check if we are the ones using this code */
 #if defined(YAPOR) || defined(THREADS)
-	LOCK(ap->PELock);
+	PELOCK(2, ap);
 	PP = ap;
 	DEC_CLREF_COUNT(cl);
 	/* clear the entry from the trail */
@@ -1492,7 +1492,7 @@ Yap_absmi(int inp)
 	GONext();
       }
       PP = PREG->u.p.p;
-      LOCK(PP->PELock);
+      PELOCK(3, PP);
 #endif
       PREG = NEXTOP(PREG, p);
       GONext();
@@ -1676,7 +1676,7 @@ Yap_absmi(int inp)
 
       /* spy_or_trymark                   */
       BOp(spy_or_trymark, Otapl);
-      LOCK(((PredEntry *)(PREG->u.Otapl.p))->PELock);
+      PELOCK(5, ((PredEntry *)(PREG->u.Otapl.p)));
       PREG = (yamop *)(&(((PredEntry *)(PREG->u.Otapl.p))->OpcodeOfPred));
       UNLOCK(((PredEntry *)(PREG->u.Otapl.p))->PELock);
       goto dospy;
@@ -1691,7 +1691,7 @@ Yap_absmi(int inp)
       CUT_wait_leftmost();
 #endif /* YAPOR */
       if (PREG->u.Otapl.p->PredFlags & LogUpdatePredFlag) {
-	LOCK(PREG->u.Otapl.p->PELock);
+	PELOCK(6,PREG->u.Otapl.p);
 	PP = PREG->u.Otapl.p;
       }
       if (PREG->u.Otapl.p->CodeOfPred != PREG) {
@@ -1774,7 +1774,7 @@ Yap_absmi(int inp)
       CUT_wait_leftmost();
 #endif /* YAPOR */
       /* need to make the DB stable until I get the new clause */
-      LOCK(PREG->u.Otapl.p->PELock);
+      PELOCK(7,PREG->u.Otapl.p);
       CACHE_Y(B);
       PREG = PREG->u.Otapl.d;
       LOCK(DynamicLock(PREG));
@@ -2069,7 +2069,7 @@ Yap_absmi(int inp)
 		  int erase;
 		  PredEntry *ap = cl->ClPred;
 
-		  LOCK(ap->PELock);
+		  PELOCK(8,ap);
 		  DEC_CLREF_COUNT(cl);
 		  erase = (cl->ClFlags & ErasedMask) && !(cl->ClRefCount);
 		  if (erase) {
@@ -2093,7 +2093,7 @@ Yap_absmi(int inp)
 		  int erase;
 		  PredEntry *ap = cl->ClPred;
 
-		  LOCK(ap->PELock);
+		  PELOCK(9,ap);
 		  DEC_CLREF_COUNT(cl);
 		  erase = (cl->ClFlags & ErasedMask) && !(cl->ClRefCount);
 		  if (erase) {
@@ -7813,7 +7813,7 @@ Yap_absmi(int inp)
 #if defined(YAPOR) || defined(THREADS)
       {
 	PredEntry *ap = PredFromDefCode(PREG);
- 	LOCK(ap->PELock);
+ 	PELOCK(10,ap);
 	PP = ap;
 	if (!ap->cs.p_code.NOfClauses) {
 	  FAIL();
@@ -7852,10 +7852,13 @@ Yap_absmi(int inp)
 	we must take extra care here
       */
 	if (!PP) {
-	  LOCK(ap->PELock);
+	  PELOCK(11,ap);
 	}
 	if (ap->OpcodeOfPred != INDEX_OPCODE) {
 	  /* someone was here before we were */
+	  if (!PP) {
+	    UNLOCKPE(11,ap);
+	  }
 	  PREG = ap->CodeOfPred;
 	  /* for profiler */
 	  save_pc();
@@ -7909,12 +7912,13 @@ Yap_absmi(int inp)
 	}
 #if defined(YAPOR) || defined(THREADS)
 	if (!PP) {
-	  LOCK(pe->PELock);
+	  PELOCK(12,pe);
 	}
 	if (!same_lu_block(PREG_ADDR, PREG)) {
 	  PREG = *PREG_ADDR;
-	  if (!PP)
+	  if (!PP) {
 	    UNLOCK(pe->PELock);
+	  }
 	  JMPNext();
 	}
 #endif
@@ -7930,9 +7934,10 @@ Yap_absmi(int inp)
 #endif /* SHADOW_S */
  	PREG = pt0;
 #if defined(YAPOR) || defined(THREADS)
-	if (!PP)
+	if (!PP) {
+	  UNLOCKPE(12,pe);
+	}
 #endif
-	  UNLOCK(pe->PELock);
 	JMPNext();
       }
       ENDBOp();
@@ -7949,7 +7954,7 @@ Yap_absmi(int inp)
 	}
 #if defined(YAPOR) || defined(THREADS)
 	if (PP == NULL) {
-	  LOCK(pe->PELock);
+	  PELOCK(13,pe);
 	}
 	if (!same_lu_block(PREG_ADDR, PREG)) {
 	  PREG = *PREG_ADDR;
@@ -8048,7 +8053,7 @@ Yap_absmi(int inp)
       {
 	PredEntry *pe = PredFromDefCode(PREG);
 	BEGD(d0);
- 	LOCK(pe->PELock);
+ 	PELOCK(14,pe);
 	if (!(pe->PredFlags & IndexedPredFlag) &&
 	      pe->cs.p_code.NOfClauses > 1) {
 	  /* update ASP before calling IPred */
@@ -8446,7 +8451,7 @@ Yap_absmi(int inp)
 #if defined(YAPOR) || defined(THREADS)
 	if (!PP) {
 	  PP = PREG->u.OtaLl.d->ClPred;
-	  LOCK(PP->PELock);
+	  PELOCK(15,PP);
 	}
 #endif
 	timestamp = IntegerOfTerm(((CELL *)(B_YREG+1))[PREG->u.OtaLl.s]);
@@ -8485,7 +8490,7 @@ Yap_absmi(int inp)
 	/* fprintf(stderr,"- %p/%p %d %d %p\n",PREG,ap,timestamp,ap->TimeStampOfPred,PREG->u.OtILl.d->ClCode);*/
 #if defined(YAPOR) || defined(THREADS)
 	if (!PP) {
-	  LOCK(ap->PELock);
+	  PELOCK(16,ap);
 	  PP = ap;
 	}
 #endif
diff --git a/C/cdmgr.c b/C/cdmgr.c
index c95cb3124..57abb17cb 100644
--- a/C/cdmgr.c
+++ b/C/cdmgr.c
@@ -2112,7 +2112,7 @@ addclause(Term t, yamop *cp, int mode, Term mod, Term *t4ref)
     p = RepPredProp(PredPropByFunc(f, mod));
   }
   Yap_PutValue(AtomAbol, TermNil);
-  LOCK(p->PELock);
+  PELOCK(20,p);
   pflags = p->PredFlags;
   /* we are redefining a prolog module predicate */
   if ((pflags & (UserCPredFlag|CArgsPredFlag|NumberDBPredFlag|AtomDBPredFlag|TestPredFlag|AsmPredFlag|CPredFlag|BinaryPredFlag)) ||
@@ -2731,7 +2731,7 @@ p_purge_clauses(void)
     pred = RepPredProp(PredPropByFunc(fun, mod));
   } else
     return (FALSE);
-  LOCK(pred->PELock);
+  PELOCK(21,pred);
   if (pred->PredFlags & StandardPredFlag) {
     UNLOCK(pred->PELock);
     Yap_Error(PERMISSION_ERROR_MODIFY_STATIC_PROCEDURE, t, "assert/1");
@@ -2774,7 +2774,7 @@ p_setspy(void)
   } else {
     return (FALSE);
   }
-  LOCK(pred->PELock);
+  PELOCK(22,pred);
  restart_spy:
   if (pred->PredFlags & (CPredFlag | SafePredFlag)) {
     UNLOCK(pred->PELock);
@@ -2829,7 +2829,7 @@ p_rmspy(void)
     pred = RepPredProp(Yap_PredPropByFunctorNonThreadLocal(fun, mod));
   } else
     return FALSE;
-  LOCK(pred->PELock);
+  PELOCK(23,pred);
   if (!(pred->PredFlags & SpiedPredFlag)) {
     UNLOCK(pred->PELock);
     return FALSE;
@@ -2897,7 +2897,7 @@ p_number_of_clauses(void)
   }
   if (EndOfPAEntr(pe))
     return FALSE;
-  LOCK(RepPredProp(pe)->PELock);
+  PELOCK(24,RepPredProp(pe));
   ncl = RepPredProp(pe)->cs.p_code.NOfClauses;
   UNLOCK(RepPredProp(pe)->PELock);
   return (Yap_unify_constant(ARG3, MkIntegerTerm(ncl)));
@@ -2912,7 +2912,7 @@ p_in_use(void)
   pe = get_pred(Deref(ARG1),  Deref(ARG2), "$in_use");
   if (EndOfPAEntr(pe))
     return FALSE;
-  LOCK(pe->PELock);
+  PELOCK(25,pe);
   out = static_in_use(pe,TRUE);
   UNLOCK(pe->PELock);
   return(out);
@@ -2944,7 +2944,7 @@ p_new_multifile(void)
     pe = RepPredProp(PredPropByAtom(at, mod));
   else 
     pe = RepPredProp(PredPropByFunc(Yap_MkFunctor(at, arity),mod));
-  LOCK(pe->PELock);
+  PELOCK(26,pe);
   pe->PredFlags |= MultiFileFlag;
   if (pe->ModuleOfPred == PROLOG_MODULE)
     pe->ModuleOfPred = TermProlog;
@@ -2966,7 +2966,7 @@ p_is_multifile(void)
   pe = get_pred(Deref(ARG1),  Deref(ARG2), "$is_multifile");
   if (EndOfPAEntr(pe))
     return FALSE;
-  LOCK(pe->PELock);
+  PELOCK(27,pe);
   out = (pe->PredFlags & MultiFileFlag);
   UNLOCK(pe->PELock);
   return(out);
diff --git a/C/compiler.c b/C/compiler.c
index 6dc821443..9816daccf 100755
--- a/C/compiler.c
+++ b/C/compiler.c
@@ -758,7 +758,7 @@ c_arg(Int argno, Term t, unsigned int arity, unsigned int level, compiler_struct
       pop_code(level, cglobs);
     }
   } else if (IsRefTerm(t)) {
-    LOCK(cglobs->cint.CurrentPred->PELock);
+    PELOCK(40,cglobs->cint.CurrentPred);
     if (!(cglobs->cint.CurrentPred->PredFlags & (DynamicPredFlag|LogUpdatePredFlag))) {
       UNLOCK(cglobs->cint.CurrentPred->PELock);
       FAIL("can not compile data base reference",TYPE_ERROR_CALLABLE,t);
@@ -1466,7 +1466,7 @@ c_goal(Term Goal, Term mod, compiler_struct *cglobs)
       if (cglobs->onlast) {
 	Yap_emit(deallocate_op, Zero, Zero, &cglobs->cint);
 #ifdef TABLING
-	LOCK(cglobs->cint.CurrentPred->PELock);
+	PELOCK(41,cglobs->cint.CurrentPred);
 	if (is_tabled(cglobs->cint.CurrentPred))
 	  Yap_emit(table_new_answer_op, Zero, cglobs->cint.CurrentPred->ArityOfPE, &cglobs->cint);
 	else
@@ -1487,7 +1487,7 @@ c_goal(Term Goal, Term mod, compiler_struct *cglobs)
 	/* never a problem here with a -> b, !, c ; d */
 	Yap_emit(deallocate_op, Zero, Zero, &cglobs->cint);
 #ifdef TABLING
-	LOCK(cglobs->cint.CurrentPred->PELock);
+	PELOCK(42,cglobs->cint.CurrentPred);
 	if (is_tabled(cglobs->cint.CurrentPred)) {
 	  Yap_emit_3ops(cut_op, Zero, Zero, Zero, &cglobs->cint);
 	  Yap_emit(table_new_answer_op, Zero, cglobs->cint.CurrentPred->ArityOfPE, &cglobs->cint);
@@ -1535,7 +1535,7 @@ c_goal(Term Goal, Term mod, compiler_struct *cglobs)
       Yap_emit(label_op, l2, Zero, &cglobs->cint);
       if (cglobs->onlast) {
 #ifdef TABLING
-	LOCK(cglobs->cint.CurrentPred->PELock);
+	PELOCK(43,cglobs->cint.CurrentPred);
 	if (is_tabled(cglobs->cint.CurrentPred))
 	  Yap_emit(table_new_answer_op, Zero, cglobs->cint.CurrentPred->ArityOfPE, &cglobs->cint);
 	else
@@ -1781,7 +1781,7 @@ c_goal(Term Goal, Term mod, compiler_struct *cglobs)
       if (cglobs->onlast) {
 	Yap_emit(deallocate_op, Zero, Zero, &cglobs->cint);
 #ifdef TABLING
-	LOCK(cglobs->cint.CurrentPred->PELock);
+	PELOCK(44,cglobs->cint.CurrentPred);
 	if (is_tabled(cglobs->cint.CurrentPred))
 	  Yap_emit(table_new_answer_op, Zero, cglobs->cint.CurrentPred->ArityOfPE, &cglobs->cint);
 	else
@@ -1811,7 +1811,7 @@ c_goal(Term Goal, Term mod, compiler_struct *cglobs)
 	if (cglobs->onlast) {
 	  Yap_emit(deallocate_op, Zero, Zero, &cglobs->cint);
 #ifdef TABLING
-	  LOCK(cglobs->cint.CurrentPred->PELock);
+	  PELOCK(45,cglobs->cint.CurrentPred);
 	  if (is_tabled(cglobs->cint.CurrentPred))
 	    Yap_emit(table_new_answer_op, Zero, cglobs->cint.CurrentPred->ArityOfPE, &cglobs->cint);
 	  else
@@ -1843,7 +1843,7 @@ c_goal(Term Goal, Term mod, compiler_struct *cglobs)
 	if (cglobs->onlast) {
 	  Yap_emit(deallocate_op, Zero, Zero, &cglobs->cint);
 #ifdef TABLING
-	  LOCK(cglobs->cint.CurrentPred->PELock);
+	  PELOCK(46,cglobs->cint.CurrentPred);
 	  if (is_tabled(cglobs->cint.CurrentPred))
 	    Yap_emit(table_new_answer_op, Zero, cglobs->cint.CurrentPred->ArityOfPE, &cglobs->cint);
 	  else
@@ -1926,7 +1926,7 @@ c_goal(Term Goal, Term mod, compiler_struct *cglobs)
       if (cglobs->onlast) {
 	Yap_emit(deallocate_op, Zero, Zero, &cglobs->cint);
 #ifdef TABLING
-	LOCK(cglobs->cint.CurrentPred->PELock);
+	PELOCK(47,cglobs->cint.CurrentPred);
 	if (is_tabled(cglobs->cint.CurrentPred))
 	  Yap_emit(table_new_answer_op, Zero, cglobs->cint.CurrentPred->ArityOfPE, &cglobs->cint);
 	else
@@ -1961,7 +1961,7 @@ c_goal(Term Goal, Term mod, compiler_struct *cglobs)
     if (cglobs->onlast) {
       Yap_emit(deallocate_op, Zero, Zero, &cglobs->cint);
 #ifdef TABLING
-      LOCK(cglobs->cint.CurrentPred->PELock);
+      PELOCK(48,cglobs->cint.CurrentPred);
       if (is_tabled(cglobs->cint.CurrentPred))
 	Yap_emit(table_new_answer_op, Zero, cglobs->cint.CurrentPred->ArityOfPE, &cglobs->cint);
       else
@@ -1993,7 +1993,7 @@ c_goal(Term Goal, Term mod, compiler_struct *cglobs)
 	Yap_emit(deallocate_op, Zero, Zero, &cglobs->cint);
 	cglobs->or_found = TRUE;
 #ifdef TABLING
-	LOCK(cglobs->cint.CurrentPred->PELock);
+	PELOCK(49,cglobs->cint.CurrentPred);
 	if (is_tabled(cglobs->cint.CurrentPred))
 	  Yap_emit(table_new_answer_op, Zero, cglobs->cint.CurrentPred->ArityOfPE, &cglobs->cint);
 	else
@@ -2008,7 +2008,7 @@ c_goal(Term Goal, Term mod, compiler_struct *cglobs)
       if (cglobs->onlast) {
 	Yap_emit(deallocate_op, Zero, Zero, &cglobs->cint);
 #ifdef TABLING
-	LOCK(cglobs->cint.CurrentPred->PELock);
+	PELOCK(50,cglobs->cint.CurrentPred);
 	if (is_tabled(cglobs->cint.CurrentPred)) {
 	  cglobs->needs_env = TRUE;
 	  Yap_emit_3ops(call_op, (CELL) p0, Zero, Zero, &cglobs->cint);
@@ -2810,7 +2810,7 @@ c_layout(compiler_struct *cglobs)
 	cglobs->cint.cpc->op = nop_op;
       } else {
 #ifdef TABLING
-	LOCK(cglobs->cint.CurrentPred->PELock);
+	PELOCK(51,cglobs->cint.CurrentPred);
 	if (is_tabled(cglobs->cint.CurrentPred))
 	  cglobs->cint.cpc->op = nop_op;
 	else
@@ -3460,7 +3460,7 @@ Yap_cclause(volatile Term inp_clause, Int NOfArgs, Term mod, volatile Term src)
       cglobs.cint.CurrentPred = RepPredProp(PredPropByFunc(FunctorOfTerm(head),mod));
     }
     /* insert extra instructions to count calls */
-    LOCK(cglobs.cint.CurrentPred->PELock);
+    PELOCK(52,cglobs.cint.CurrentPred);
     if ((cglobs.cint.CurrentPred->PredFlags & ProfiledPredFlag) ||
 	(PROFILING && (cglobs.cint.CurrentPred->cs.p_code.FirstClause == NIL))) {
       profiling = TRUE;
@@ -3482,7 +3482,7 @@ Yap_cclause(volatile Term inp_clause, Int NOfArgs, Term mod, volatile Term src)
 
   if (cglobs.is_a_fact && !cglobs.vtable) {
 #ifdef TABLING
-    LOCK(cglobs.cint.CurrentPred->PELock);
+    PELOCK(53,cglobs.cint.CurrentPred);
     if (is_tabled(cglobs.cint.CurrentPred))
       Yap_emit(table_new_answer_op, Zero, cglobs.cint.CurrentPred->ArityOfPE, &cglobs.cint);
     else
diff --git a/C/dbase.c b/C/dbase.c
index aa06d8554..98a89fc9c 100755
--- a/C/dbase.c
+++ b/C/dbase.c
@@ -1895,7 +1895,7 @@ record_lu_at(int position, LogUpdClause *ocl, Term t)
   PredEntry *pe;
 
   pe = ocl->ClPred;
-  LOCK(pe->PELock);
+  PELOCK(62,pe);
   if ((cl = new_lu_db_entry(t,pe)) == NULL) {
     UNLOCK(pe->PELock);
     return NULL;
@@ -1951,7 +1951,7 @@ p_rcda(void)
   if (pe) {
     LogUpdClause *cl;
 
-    LOCK(pe->PELock);
+    PELOCK(61,pe);
     cl = record_lu(pe, Deref(ARG2), MkFirst);
     if (cl != NULL) {
       TRAIL_CLREF(cl);
@@ -2061,7 +2061,7 @@ p_rcdz(void)
   if (pe) {
     LogUpdClause *cl;
 
-    LOCK(pe->PELock);
+    PELOCK(62,pe);
     cl = record_lu(pe, t2, MkLast);
     if (cl != NULL) {
       TRAIL_CLREF(cl);
@@ -2367,7 +2367,7 @@ copy_attachments(CELL *ts)
 static Term
 GetDBLUKey(PredEntry *ap)
 {
-  LOCK(ap->PELock);
+  PELOCK(63,ap);
   if (ap->PredFlags & NumberDBPredFlag) {
     Int id = ap->src.IndxId;
     UNLOCK(ap->PELock);
@@ -2867,7 +2867,7 @@ FetchDBPropFromKey(Term twork, int flag, int new, char *error_mssg)
 	pp = RepPredProp(Yap_GetPredPropHavingLock(At, arity, dbmod));
 
 	if (!EndOfPAEntr(pp)) {
-	  LOCK(pp->PELock);
+	  PELOCK(64,pp);
 	  if(pp->PredFlags & LogUpdatePredFlag)
 	    UPDATE_MODE = UPDATE_MODE_LOGICAL;
 	  UNLOCK(pp->PELock);
@@ -2909,7 +2909,7 @@ lu_nth_recorded(PredEntry *pe, Int Count)
   if (cl == NULL)
     return FALSE;
 #if defined(YAPOR) || defined(THREADS)
-  LOCK(pe->PELock);
+  PELOCK(65,pe);
   TRAIL_CLREF(cl);		/* So that fail will erase it */
   INC_CLREF_COUNT(cl);
   UNLOCK(pe->PELock);
@@ -2991,7 +2991,7 @@ p_nth_instance(void)
 	Term pred_module;
 
 	pe = cl->ClPred;
-	LOCK(pe->PELock);
+	PELOCK(66,pe);
 	if (cl->ClFlags & ErasedMask) {
 	  UNLOCK(pe->PELock);
 	  return FALSE;
@@ -3436,7 +3436,7 @@ lu_recorded(PredEntry *pe) {
   op_numbers opc = Yap_op_from_opcode(P->opc);
 
 #if defined(YAPOR) || defined(THREADS)
-  LOCK(pe->PELock);
+  PELOCK(66,pe);
   PP = pe;
 #endif
   if (opc == _procceed) {
@@ -4349,7 +4349,7 @@ EraseEntry(DBRef entryref)
   if (entryref->Flags & LogUpdMask &&
       !(entryref->Flags & DBClMask)) {
     LogUpdClause *luclause = (LogUpdClause *)entryref;
-    LOCK(luclause->ClPred->PELock);
+    PELOCK(67,luclause->ClPred);
     EraseLogUpdCl(luclause);
     UNLOCK(luclause->ClPred->PELock);
     return;
@@ -4611,7 +4611,7 @@ p_instance(void)
     LogUpdClause *cl = (LogUpdClause *)dbr;
     PredEntry *ap = cl->ClPred;
 
-    LOCK(ap->PELock);
+    PELOCK(68,ap);
     if (cl->ClFlags & ErasedMask) {
       UNLOCK(ap->PELock);
       return FALSE;
@@ -5413,7 +5413,7 @@ p_install_thread_local(void)
   } else {
     return FALSE;
   }
-  LOCK(pe->PELock);
+  PELOCK(69,pe);
   if (pe->PredFlags & (UserCPredFlag|HiddenPredFlag|CArgsPredFlag|SyncPredFlag|TestPredFlag|AsmPredFlag|StandardPredFlag|CPredFlag|SafePredFlag|IndexedPredFlag|BinaryPredFlag) ||
       pe->cs.p_code.NOfClauses) {
     return FALSE;
diff --git a/C/errors.c b/C/errors.c
index f5cfe1688..6cec4dbfd 100644
--- a/C/errors.c
+++ b/C/errors.c
@@ -67,7 +67,7 @@ legal_env (CELL *ep)
     return (FALSE);
   ps = *((CELL *) (Addr (cp) - CellSize));
   pe = (PredEntry *) (ps - sizeof (OPREG) - sizeof (Prop));
-  LOCK(pe->PELock);
+  PELOCK(70,pe);
   if (!ONHEAP (pe) || Unsigned (pe) & 3 || pe->KindOfPE & 0xff00) {
     UNLOCK(pe->PELock);
     return (FALSE);
@@ -100,7 +100,7 @@ DumpActiveGoals (void)
       pe = EnvPreg((yamop *)cp);
       if (!ONHEAP (pe) || Unsigned (pe) & (sizeof(CELL)-1))
 	break;
-      LOCK(pe->PELock);
+      PELOCK(71,pe);
       if (pe->KindOfPE & 0xff00) {
 	UNLOCK(pe->PELock);
 	break;
@@ -142,7 +142,7 @@ DumpActiveGoals (void)
       if (!ONLOCAL (b_ptr) || b_ptr->cp_b == NULL)
 	break;
       pe = Yap_PredForChoicePt(b_ptr);
-      LOCK(pe->PELock);
+      PELOCK(72,pe);
       {
 	Functor f;
 	Term mod = PROLOG_MODULE;
diff --git a/C/exec.c b/C/exec.c
index e8a5faffd..a20eda539 100644
--- a/C/exec.c
+++ b/C/exec.c
@@ -795,7 +795,7 @@ p_execute_nonstop(void)
 #if defined(YAPOR) || defined(THREADS)
     if (RepPredProp(pe)->PredFlags & LogUpdatePredFlag) {
       PP = RepPredProp(pe);
-      LOCK(PP->PELock);
+      PELOCK(80,PP);
     }
 #endif
     return CallPredicate(RepPredProp(pe), B, RepPredProp(pe)->cs.p_code.TrueCodeOfPred);
@@ -1119,7 +1119,7 @@ Yap_execute_goal(Term t, int nargs, Term mod)
   if (pe == NIL) {
     return(CallMetaCall(mod));
   }
-  LOCK(ppe->PELock);
+  PELOCK(81,ppe);
   if (IsAtomTerm(t)) {
     CodeAdr = RepPredProp (pe)->CodeOfPred;
     UNLOCK(ppe->PELock);
@@ -1271,7 +1271,7 @@ Yap_RunTopGoal(Term t)
     /* we must always start the emulator with Prolog code */
     return FALSE;
   }
-  LOCK(ppe->PELock);
+  PELOCK(82,ppe);
   CodeAdr = ppe->CodeOfPred;
   UNLOCK(ppe->PELock);
 #if !USE_SYSTEM_MALLOC
diff --git a/C/heapgc.c b/C/heapgc.c
index fd7f6fafe..243709de1 100755
--- a/C/heapgc.c
+++ b/C/heapgc.c
@@ -2546,7 +2546,7 @@ sweep_trail(choiceptr gc_B, tr_fr_ptr old_TR)
 		*/
 		PredEntry *ap = indx->ClPred;
 		if (ap != PP)
-		  LOCK(ap->PELock);
+		  PELOCK(85,ap);
 #endif
 		DEC_CLREF_COUNT(indx);
 		indx->ClFlags &= ~InUseMask;
@@ -2570,7 +2570,7 @@ sweep_trail(choiceptr gc_B, tr_fr_ptr old_TR)
 
 #if  defined(YAPOR) || defined(THREADS)
 		if (ap != PP)
-		    LOCK(ap->PELock);
+		  PELOCK(86,ap);
 #endif
 		DEC_CLREF_COUNT(cl);
 		cl->ClFlags &= ~InUseMask;
diff --git a/C/init.c b/C/init.c
index 2874b369b..e729322ed 100755
--- a/C/init.c
+++ b/C/init.c
@@ -1159,7 +1159,6 @@ InitFirstWorkerThreadHandle(void)
   ThreadHandle.default_yaam_regs = 
     &Yap_standard_regs;
   ThreadHandle.pthread_handle = pthread_self();
-  ThreadHandle.pthread_handle = pthread_self();
   pthread_mutex_init(&FOREIGN_ThreadHandle(0).tlock, NULL);
   pthread_mutex_init(&FOREIGN_ThreadHandle(0).tlock_status, NULL);
   ThreadHandle.tdetach = MkAtomTerm(AtomFalse);
diff --git a/C/stdpreds.c b/C/stdpreds.c
index 1818538d7..17bdd14c0 100755
--- a/C/stdpreds.c
+++ b/C/stdpreds.c
@@ -607,7 +607,7 @@ FindAtom(codeToFind, arity)
 	pp = RepPredProp(pp->NextOfPE);
       if (pp != NIL) {
 	CODEADDR *out;
-	LOCK(pp->PELock);
+	PELOCK(90,pp);
 	out = &(pp->CodeOfPred)
 	*arityp = pp->ArityOfPE;
 	UNLOCK(pp->PELock);
@@ -632,7 +632,7 @@ FindAtom(codeToFind, arity)
 	pp = RepPredProp(pp->NextOfPE);
       if (pp != NIL) {
 	CODEADDR *out;
-	LOCK(pp->PELock);
+	PELOCK(91,pp);
 	out = &(pp->CodeOfPred)
 	*arityp = pp->ArityOfPE;
 	UNLOCK(pp->PELock);
@@ -3124,7 +3124,7 @@ p_flags(void)
     return (FALSE);
   if (EndOfPAEntr(pe))
     return (FALSE);
-  LOCK(pe->PELock);
+  PELOCK(92,pe);
   if (!Yap_unify_constant(ARG3, MkIntegerTerm(pe->PredFlags))) {
     UNLOCK(pe->PELock);
     return(FALSE);
diff --git a/C/utilpreds.c b/C/utilpreds.c
index 3a8bf3e4d..bdedb4e11 100644
--- a/C/utilpreds.c
+++ b/C/utilpreds.c
@@ -154,7 +154,7 @@ copy_complex_term(CELL *pt0, CELL *pt0_end, int share, int newattvs, CELL *ptf,
 	    DBRef  entryref = DBRefOfTerm(d0);
 	    if (entryref->Flags & LogUpdMask) {
 	      LogUpdClause *luclause = (LogUpdClause *)entryref;
-	      LOCK(luclause->ClPred->PELock);
+	      PELOCK(100,luclause->ClPred);
 	      UNLOCK(luclause->ClPred->PELock);
 	    } else {
 	      LOCK(entryref->lock);
diff --git a/H/YapHeap.h b/H/YapHeap.h
index dc43eb001..40eb0cfd9 100755
--- a/H/YapHeap.h
+++ b/H/YapHeap.h
@@ -128,6 +128,9 @@ typedef struct thandle {
   long long int thread_inst_count;
   int been_here1;
   int been_here2;
+#endif
+#ifdef DEBUG
+  int been_here;
 #endif
   pthread_mutex_t tlock;
   pthread_mutex_t tlock_status;
diff --git a/H/Yatom.h b/H/Yatom.h
index b3a4f63e6..237b66823 100755
--- a/H/Yatom.h
+++ b/H/Yatom.h
@@ -1520,4 +1520,14 @@ PredPropByAtom (Atom at, Term cur_mod)
   return Yap_NewPredPropByAtom (ae, cur_mod);
 }
 
+#if DEBUG_PELOCKING
+#define PELOCK(I,Z)						\
+  { LOCK((Z)->PELock); (Z)->StatisticsForPred.NOfEntries=(I),(Z)->StatisticsForPred.NOfHeadSuccesses=pthread_self(); }
+#define UNLOCKPE(I,Z)						\
+  ( (Z)->StatisticsForPred.NOfRetries=(I),  UNLOCK((Z)->PELock) )
+#else
+#define PELOCK(I,Z) LOCK((Z)->PELock)
+#define UNLOCKPE(I,Z)	UNLOCK((Z)->PELock)
+#endif
+
 #endif