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59 lines
1.2 KiB
C
59 lines
1.2 KiB
C
/*-
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* See the file LICENSE for redistribution information.
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*
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* Copyright (c) 1997, 1998, 1999, 2000
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* Sleepycat Software. All rights reserved.
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*/
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#include "db_config.h"
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#ifndef lint
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static const char revid[] = "$Id: os_spin.c,v 11.6 2000/05/17 19:30:19 bostic Exp $";
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#endif /* not lint */
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#include "db_int.h"
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#include "os_jump.h"
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/*
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* __os_spin --
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* Return the number of default spins before blocking.
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*/
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int
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__os_spin()
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{
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SYSTEM_INFO SystemInfo;
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/*
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* If the application specified a value or we've already figured it
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* out, return it.
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*/
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if (DB_GLOBAL(db_tas_spins) != 0)
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return (DB_GLOBAL(db_tas_spins));
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/* Get the number of processors */
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GetSystemInfo(&SystemInfo);
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/*
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* Spin 50 times per processor -- we have anecdotal evidence that this
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* is a reasonable value.
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*/
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if (SystemInfo.dwNumberOfProcessors > 1)
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DB_GLOBAL(db_tas_spins) = 50 * SystemInfo.dwNumberOfProcessors;
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else
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DB_GLOBAL(db_tas_spins) = 1;
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return (DB_GLOBAL(db_tas_spins));
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}
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/*
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* __os_yield --
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* Yield the processor.
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*/
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void
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__os_yield(dbenv, usecs)
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DB_ENV *dbenv;
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u_long usecs;
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{
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if (__db_jump.j_yield != NULL && __db_jump.j_yield() == 0)
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return;
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__os_sleep(dbenv, 0, usecs);
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}
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