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C $Header: /u/u0/gcmpack/MITgcm/eesupp/src/bar2.F,v 1.5 2004/03/27 03:51:50 edhill Exp $ |
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C $Name: $ |
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#include "CPP_EEOPTIONS.h" |
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|
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CBOP |
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C !ROUTINE: BAR2_INIT |
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|
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C !INTERFACE: |
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SUBROUTINE BAR2_INIT( myThid ) |
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IMPLICIT NONE |
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|
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C !DESCRIPTION: |
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C *=====================================================================* |
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C | SUBROUTINE BAR2\_INIT |
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C | o Setup global barrier data structures. |
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C *=====================================================================* |
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C | Initialise global barrier data structures that can be used in |
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C | conjunction with MPI or that can also be used to create |
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C *=====================================================================* |
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|
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C !USES: |
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C == Global variables == |
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#include "SIZE.h" |
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#include "EEPARAMS.h" |
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#include "EESUPPORT.h" |
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#include "BAR2.h" |
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C |
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|
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C !INPUT/OUTPUT PARAMETERS: |
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C == Routine arguments == |
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C myThid :: Thread number of this instance of BAR2_INIT |
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INTEGER myThid |
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|
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C !LOCAL VARIABLES: |
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C == Local variables == |
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C I :: Loop counter |
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INTEGER I |
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CEOP |
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|
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C |
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DO I = 1, lShare4 |
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BAR2_level(I,myThid) = 0 |
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BAR2_barrierCount(I,myThid) = 0 |
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BAR2_spinsCount(I,myThid) = 0 |
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BAR2_spinsCount(I,myThid) = 0 |
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BAR2_spinsMax (I,myThid) = 0 |
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BAR2_spinsMin (I,myThid) = 1000000000 |
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ENDDO |
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C |
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bar2CollectStatistics = .TRUE. |
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C |
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RETURN |
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END |
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|
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CBOP |
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|
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C !ROUTINE: BAR2 |
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|
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C !INTERFACE: |
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SUBROUTINE BAR2( myThid ) |
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IMPLICIT NONE |
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|
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C !DESCRIPTION: |
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C *=====================================================================* |
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C | SUBROUTINE BAR2 |
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C | o Global barrier routine. |
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C *=====================================================================* |
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C | Implements a simple true shared memory barrier that uses a global |
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C | heap array that all threads can access to synchronise. Each thread |
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C | writes to a predefined location. One thread polls the locations. Other |
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C | threads poll an all clear assertion location. Once the polling |
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C | thread that is looping over locations sees writes for each thread is |
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C | writes the all clear assertion location and everyone proceeds. A |
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C | cyclic series of locations is used to ensure that race conditions do |
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C | not occur. A few simple statistics are recorded giving number of |
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C | barrier calls, max, min and aggregate polling loop counts. |
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C *=====================================================================* |
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|
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C !USES: |
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C == Global variables == |
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#include "SIZE.h" |
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#include "EEPARAMS.h" |
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#include "EESUPPORT.h" |
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#include "BAR2.h" |
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|
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C !INPUT/OUTPUT PARAMETERS: |
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C == Routine arguments == |
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C myThid :: Thread number of this instance of BAR2 |
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INTEGER myThid |
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|
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C !LOCAL VARIABLES: |
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C == Local variables == |
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C myLevel :: Temp. to hold "active" barrier level |
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C nDone :: Temp. for counting number of threads that |
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C have reached the barrier. |
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C I :: Loop counter |
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C spinCount :: Temp. for doing statistics on how many |
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C times barrier code looped. |
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INTEGER myLevel |
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INTEGER nDone |
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INTEGER I |
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INTEGER spinCount |
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CEOP |
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|
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#ifdef USE_OMP_THREADING |
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C$OMP BARRIER |
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BAR2_barrierCount(1,myThid) = BAR2_barrierCount(1,myThid)+1 |
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Cdbg C$OMP BARRIER |
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Cdbg DO I = 2, nThreads |
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Cdbg IF ( BAR2_barrierCount(1,I) .NE. BAR2_barrierCount(1,1) ) THEN |
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Cdbg PRINT *, BAR2_barrierCount(1,1:nThreads) |
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Cdbg CALL SYSTEM('sleep 1') |
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Cdbg PRINT *, BAR2_barrierCount(1,1:nThreads) |
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Cdbg Stop ' bar2 OUT OF SYNC ' |
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Cdbg ENDIF |
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Cdbg ENDDO |
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Cdbg C$OMP BARRIER |
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RETURN |
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#endif |
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|
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C |
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spinCount = 0 |
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C |
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IF ( myThid .NE. 1 ) THEN |
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|
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BAR2_level(1,myThid) = BAR2_level(1,myThid)+1 |
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myLevel = BAR2_level(1,myThid) |
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10 CONTINUE |
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IF ( BAR2_level(1,1) .EQ. myLevel ) GOTO 11 |
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spinCount = spinCount+1 |
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CALL FOOL_THE_COMPILER( BAR2_level ) |
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GOTO 10 |
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11 CONTINUE |
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|
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ELSE |
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|
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myLevel = BAR2_level(1,1) |
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12 CONTINUE |
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CALL FOOL_THE_COMPILER( BAR2_level ) |
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nDone = 1 |
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DO I = 2, nThreads |
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IF ( BAR2_level(1,1) .EQ. BAR2_level(1,I)-1 ) nDone = nDone+1 |
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ENDDO |
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spinCount = spinCount+1 |
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IF ( nDone .LT. nThreads ) GOTO 12 |
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|
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BAR2_level(1,1) = myLevel+1 |
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|
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ENDIF |
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C |
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BAR2_barrierCount(1,myThid) = BAR2_barrierCount(1,myThid)+1 |
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BAR2_spinsCount(1,myThid) = BAR2_spinsCount(1,myThid)+spinCount |
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BAR2_spinsMax (1,myThid) = MAX(BAR2_spinsMax(1,myThid),spinCount) |
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BAR2_spinsMin (1,myThid) = MIN(BAR2_spinsMin(1,myThid),spinCount) |
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C |
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RETURN |
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END |
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