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/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1997-2002
* Sleepycat Software. All rights reserved.
*/
#include "db_config.h"
#ifndef lint
static const char revid[] = "$Id: os_spin.c,v 1.1.1.1 2003/11/20 22:13:39 toshok Exp $";
#endif /* not lint */
#include "db_int.h"
/*
* __os_spin --
* Return the number of default spins before blocking.
*/
int
__os_spin(dbenv)
DB_ENV *dbenv;
{
SYSTEM_INFO SystemInfo;
/*
* If the application specified a value or we've already figured it
* out, return it.
*/
if (dbenv->tas_spins != 0)
return (dbenv->tas_spins);
/* 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)
dbenv->tas_spins = 50 * SystemInfo.dwNumberOfProcessors;
else
dbenv->tas_spins = 1;
return (dbenv->tas_spins);
}
/*
* __os_yield --
* Yield the processor.
*/
void
__os_yield(dbenv, usecs)
DB_ENV *dbenv;
u_long usecs;
{
if (DB_GLOBAL(j_yield) != NULL && DB_GLOBAL(j_yield)() == 0)
return;
__os_sleep(dbenv, 0, usecs);
}
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