1*0Sstevel@tonic-gate /*- 2*0Sstevel@tonic-gate * See the file LICENSE for redistribution information. 3*0Sstevel@tonic-gate * 4*0Sstevel@tonic-gate * Copyright (c) 1997, 1998 5*0Sstevel@tonic-gate * Sleepycat Software. All rights reserved. 6*0Sstevel@tonic-gate */ 7*0Sstevel@tonic-gate 8*0Sstevel@tonic-gate #include "config.h" 9*0Sstevel@tonic-gate 10*0Sstevel@tonic-gate #ifndef lint 11*0Sstevel@tonic-gate static const char sccsid[] = "@(#)os_spin.c 10.10 (Sleepycat) 10/12/98"; 12*0Sstevel@tonic-gate #endif /* not lint */ 13*0Sstevel@tonic-gate 14*0Sstevel@tonic-gate #ifndef NO_SYSTEM_INCLUDES 15*0Sstevel@tonic-gate #include <sys/types.h> 16*0Sstevel@tonic-gate #if defined(HAVE_PSTAT_GETDYNAMIC) 17*0Sstevel@tonic-gate #include <sys/pstat.h> 18*0Sstevel@tonic-gate #endif 19*0Sstevel@tonic-gate 20*0Sstevel@tonic-gate #include <limits.h> 21*0Sstevel@tonic-gate #include <unistd.h> 22*0Sstevel@tonic-gate #endif 23*0Sstevel@tonic-gate 24*0Sstevel@tonic-gate #include "db_int.h" 25*0Sstevel@tonic-gate #include "os_jump.h" 26*0Sstevel@tonic-gate 27*0Sstevel@tonic-gate #if defined(HAVE_PSTAT_GETDYNAMIC) 28*0Sstevel@tonic-gate /* 29*0Sstevel@tonic-gate * __os_pstat_getdynamic -- 30*0Sstevel@tonic-gate * HP/UX. 31*0Sstevel@tonic-gate */ 32*0Sstevel@tonic-gate static int __os_pstat_getdynamic()33*0Sstevel@tonic-gate__os_pstat_getdynamic() 34*0Sstevel@tonic-gate { 35*0Sstevel@tonic-gate struct pst_dynamic psd; 36*0Sstevel@tonic-gate 37*0Sstevel@tonic-gate return (pstat_getdynamic(&psd, 38*0Sstevel@tonic-gate sizeof(psd), (size_t)1, 0) == -1 ? 1 : psd.psd_proc_cnt); 39*0Sstevel@tonic-gate } 40*0Sstevel@tonic-gate #endif 41*0Sstevel@tonic-gate 42*0Sstevel@tonic-gate #if defined(HAVE_SYSCONF) && defined(_SC_NPROCESSORS_ONLN) 43*0Sstevel@tonic-gate /* 44*0Sstevel@tonic-gate * __os_sysconf -- 45*0Sstevel@tonic-gate * Solaris, Linux. 46*0Sstevel@tonic-gate */ 47*0Sstevel@tonic-gate static int __os_sysconf()48*0Sstevel@tonic-gate__os_sysconf() 49*0Sstevel@tonic-gate { 50*0Sstevel@tonic-gate int nproc; 51*0Sstevel@tonic-gate 52*0Sstevel@tonic-gate return ((nproc = sysconf(_SC_NPROCESSORS_ONLN)) > 1 ? nproc : 1); 53*0Sstevel@tonic-gate } 54*0Sstevel@tonic-gate #endif 55*0Sstevel@tonic-gate 56*0Sstevel@tonic-gate /* 57*0Sstevel@tonic-gate * __os_spin -- 58*0Sstevel@tonic-gate * Return the number of default spins before blocking. 59*0Sstevel@tonic-gate * 60*0Sstevel@tonic-gate * PUBLIC: int __os_spin __P((void)); 61*0Sstevel@tonic-gate */ 62*0Sstevel@tonic-gate int __os_spin()63*0Sstevel@tonic-gate__os_spin() 64*0Sstevel@tonic-gate { 65*0Sstevel@tonic-gate /* 66*0Sstevel@tonic-gate * If the application specified a value or we've already figured it 67*0Sstevel@tonic-gate * out, return it. 68*0Sstevel@tonic-gate * 69*0Sstevel@tonic-gate * XXX 70*0Sstevel@tonic-gate * We don't want to repeatedly call the underlying function because 71*0Sstevel@tonic-gate * it can be expensive (e.g., requiring multiple filesystem accesses 72*0Sstevel@tonic-gate * under Debian Linux). 73*0Sstevel@tonic-gate */ 74*0Sstevel@tonic-gate if (DB_GLOBAL(db_tsl_spins) != 0) 75*0Sstevel@tonic-gate return (DB_GLOBAL(db_tsl_spins)); 76*0Sstevel@tonic-gate 77*0Sstevel@tonic-gate DB_GLOBAL(db_tsl_spins) = 1; 78*0Sstevel@tonic-gate #if defined(HAVE_PSTAT_GETDYNAMIC) 79*0Sstevel@tonic-gate DB_GLOBAL(db_tsl_spins) = __os_pstat_getdynamic(); 80*0Sstevel@tonic-gate #endif 81*0Sstevel@tonic-gate #if defined(HAVE_SYSCONF) && defined(_SC_NPROCESSORS_ONLN) 82*0Sstevel@tonic-gate DB_GLOBAL(db_tsl_spins) = __os_sysconf(); 83*0Sstevel@tonic-gate #endif 84*0Sstevel@tonic-gate 85*0Sstevel@tonic-gate /* 86*0Sstevel@tonic-gate * Spin 50 times per processor, we have anecdotal evidence that this 87*0Sstevel@tonic-gate * is a reasonable value. 88*0Sstevel@tonic-gate */ 89*0Sstevel@tonic-gate DB_GLOBAL(db_tsl_spins) *= 50; 90*0Sstevel@tonic-gate 91*0Sstevel@tonic-gate return (DB_GLOBAL(db_tsl_spins)); 92*0Sstevel@tonic-gate } 93*0Sstevel@tonic-gate 94*0Sstevel@tonic-gate /* 95*0Sstevel@tonic-gate * __os_yield -- 96*0Sstevel@tonic-gate * Yield the processor. 97*0Sstevel@tonic-gate * 98*0Sstevel@tonic-gate * PUBLIC: void __os_yield __P((u_long)); 99*0Sstevel@tonic-gate */ 100*0Sstevel@tonic-gate void __os_yield(usecs)101*0Sstevel@tonic-gate__os_yield(usecs) 102*0Sstevel@tonic-gate u_long usecs; 103*0Sstevel@tonic-gate { 104*0Sstevel@tonic-gate if (__db_jump.j_yield != NULL && __db_jump.j_yield() == 0) 105*0Sstevel@tonic-gate return; 106*0Sstevel@tonic-gate __os_sleep(0, usecs); 107*0Sstevel@tonic-gate } 108