/*- * 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 10.10 (Sleepycat) 10/12/98"; #endif /* not lint */ #ifndef NO_SYSTEM_INCLUDES #include #if defined(HAVE_PSTAT_GETDYNAMIC) #include #endif #include #include #endif #include "db_int.h" #include "os_jump.h" #if defined(HAVE_PSTAT_GETDYNAMIC) /* * __os_pstat_getdynamic -- * HP/UX. */ static int __os_pstat_getdynamic() { struct pst_dynamic psd; return (pstat_getdynamic(&psd, sizeof(psd), (size_t)1, 0) == -1 ? 1 : psd.psd_proc_cnt); } #endif #if defined(HAVE_SYSCONF) && defined(_SC_NPROCESSORS_ONLN) /* * __os_sysconf -- * Solaris, Linux. */ static int __os_sysconf() { int nproc; return ((nproc = sysconf(_SC_NPROCESSORS_ONLN)) > 1 ? nproc : 1); } #endif /* * __os_spin -- * Return the number of default spins before blocking. * * PUBLIC: int __os_spin __P((void)); */ int __os_spin() { /* * If the application specified a value or we've already figured it * out, return it. * * XXX * We don't want to repeatedly call the underlying function because * it can be expensive (e.g., requiring multiple filesystem accesses * under Debian Linux). */ if (DB_GLOBAL(db_tsl_spins) != 0) return (DB_GLOBAL(db_tsl_spins)); DB_GLOBAL(db_tsl_spins) = 1; #if defined(HAVE_PSTAT_GETDYNAMIC) DB_GLOBAL(db_tsl_spins) = __os_pstat_getdynamic(); #endif #if defined(HAVE_SYSCONF) && defined(_SC_NPROCESSORS_ONLN) DB_GLOBAL(db_tsl_spins) = __os_sysconf(); #endif /* * Spin 50 times per processor, we have anecdotal evidence that this * is a reasonable value. */ DB_GLOBAL(db_tsl_spins) *= 50; return (DB_GLOBAL(db_tsl_spins)); } /* * __os_yield -- * Yield the processor. * * PUBLIC: void __os_yield __P((u_long)); */ void __os_yield(usecs) u_long usecs; { if (__db_jump.j_yield != NULL && __db_jump.j_yield() == 0) return; __os_sleep(0, usecs); }