mariadb/bdb/os_win32/os_spin.c

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/*-
* See the file LICENSE for redistribution information.
*
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* Copyright (c) 1997-2002
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* Sleepycat Software. All rights reserved.
*/
#include "db_config.h"
#ifndef lint
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static const char revid[] = "$Id: os_spin.c,v 11.11 2002/07/12 18:56:56 bostic Exp $";
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#endif /* not lint */
#include "db_int.h"
/*
* __os_spin --
* Return the number of default spins before blocking.
*/
int
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__os_spin(dbenv)
DB_ENV *dbenv;
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{
SYSTEM_INFO SystemInfo;
/*
* If the application specified a value or we've already figured it
* out, return it.
*/
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if (dbenv->tas_spins != 0)
return (dbenv->tas_spins);
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/* Get the number of processors */
GetSystemInfo(&SystemInfo);
/*
* Spin 50 times per processor -- we have anecdotal evidence that this
* is a reasonable value.
*/
if (SystemInfo.dwNumberOfProcessors > 1)
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dbenv->tas_spins = 50 * SystemInfo.dwNumberOfProcessors;
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else
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dbenv->tas_spins = 1;
return (dbenv->tas_spins);
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}
/*
* __os_yield --
* Yield the processor.
*/
void
__os_yield(dbenv, usecs)
DB_ENV *dbenv;
u_long usecs;
{
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if (DB_GLOBAL(j_yield) != NULL && DB_GLOBAL(j_yield)() == 0)
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return;
__os_sleep(dbenv, 0, usecs);
}