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C $Header: BARRIER.h,v 1.1.1.1 1998/04/22 19:15:30 cnh Exp $ |
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C |
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C /==========================================================\ |
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C | FBAR.h | |
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C | o Globals used by Fortran barrier routine. | |
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C |==========================================================| |
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C | These variables support a simple Fortran shared memory | |
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C | barrier routine. They do busy waiting, that is the | |
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C | thread that is waiting sits in a tight loop reading | |
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C | some memory location and waiting for all other threads. | |
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C | On some systems this is sometimes a good method to use. | |
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C | On the T3E memory is not shared so the routine should | |
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C | use the T3E "eureka" barriers. On CRAY and NEC there are | |
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C | hardware barriers that are accessed through a compiler | |
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C | directives. Finally proper multi-threading compilers | |
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C | support barrier compile directives - sometimes these | |
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C | are good, sometimes they are lousy. | |
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C | The barrier mechanism is used as follows | |
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C | 1. In the single-threaded part of the code | |
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C | CALL FBAR_INIT | |
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C | on CRAY, NEC this routine does nothing | |
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C | on T3E there is no single-threaded code | |
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C | but there may be barrier initialisation - | |
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C | need to check. | |
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C | 2. When we need to synchronize everybody just | |
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C | CALL FBAR( myThid ) | |
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C | where myThid is myThreadId | |
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C | on CRAY, NEC FBAR will just do C$DIR BARRIER | |
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C | or the like. | |
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C | on T3E FBAR does CALL BARRIER(...) or something | |
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C | need to check this. | |
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C \==========================================================/ |
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COMMON / BARRIER_COMMON / key1, key2, key3, |
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& door1, door2, door3 |
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INTEGER key1(lShare4,MAX_NO_THREADS) |
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INTEGER key2(lShare4,MAX_NO_THREADS) |
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INTEGER key3(lShare4,MAX_NO_THREADS) |
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INTEGER door1 |
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INTEGER door2 |
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INTEGER door3 |
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INTEGER VALID |
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PARAMETER ( VALID = 1 ) |
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INTEGER INVALID |
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PARAMETER ( INVALID = 0 ) |
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INTEGER OPEN |
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PARAMETER ( OPEN = 1 ) |
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INTEGER SHUT |
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PARAMETER ( SHUT = 0 ) |
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