gecko-dev/db/os.win32/os_spin.c

49 строки
1.0 KiB
C

/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1997, 1998
* Sleepycat Software. All rights reserved.
*/
#include "config.h"
#ifndef lint
static const char sccsid[] = "@(#)os_spin.c 10.6 (Sleepycat) 6/2/98";
#endif /* not lint */
#include "db_int.h"
/*
* __os_spin --
* Return the number of default spins before blocking.
*
* PUBLIC: int __os_spin __P((void));
*/
int
__os_spin()
{
static long sys_val;
SYSTEM_INFO SystemInfo;
/* If the application specified the spins, use its value. */
if (DB_GLOBAL(db_tsl_spins) != 0)
return (DB_GLOBAL(db_tsl_spins));
/* If we've already figured this out, return the value. */
if (sys_val != 0)
return (sys_val);
/* 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)
sys_val = 50 * SystemInfo.dwNumberOfProcessors;
else
sys_val = 1;
return (sys_val);
}