1 /* 2 * Copyright (c) 2012 Fujitsu Ltd. 3 * Author: Wanlong Gao <gaowanlong (at) cn.fujitsu.com> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation; either version 2 of the License, or 8 * (at your option) any later version. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See 13 * the GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 18 */ 19 20 #include <stdlib.h> 21 #include <unistd.h> 22 #include "test.h" 23 #include "safe_macros.h" 24 25 long tst_ncpus(void) 26 { 27 long ncpus = -1; 28 #ifdef _SC_NPROCESSORS_ONLN 29 ncpus = SAFE_SYSCONF(NULL, _SC_NPROCESSORS_ONLN); 30 #else 31 tst_brkm(TBROK, NULL, "could not determine number of CPUs online"); 32 #endif 33 return ncpus; 34 } 35 36 long tst_ncpus_conf(void) 37 { 38 long ncpus_conf = -1; 39 #ifdef _SC_NPROCESSORS_CONF 40 ncpus_conf = SAFE_SYSCONF(NULL, _SC_NPROCESSORS_CONF); 41 #else 42 tst_brkm(TBROK, NULL, "could not determine number of CPUs configured"); 43 #endif 44 return ncpus_conf; 45 } 46 47 #define KERNEL_MAX "/sys/devices/system/cpu/kernel_max" 48 49 long tst_ncpus_max(void) 50 { 51 long ncpus_max = -1; 52 struct stat buf; 53 54 /* sched_getaffinity() and sched_setaffinity() cares about number of 55 * possible CPUs the OS or hardware can support, which can be larger 56 * than what sysconf(_SC_NPROCESSORS_CONF) currently provides 57 * (by enumarating /sys/devices/system/cpu/cpu* entries). 58 * 59 * Use /sys/devices/system/cpu/kernel_max, if available. This 60 * represents NR_CPUS-1, a compile time option which specifies 61 * "maximum number of CPUs which this kernel will support". 62 * This should provide cpu mask size large enough for any purposes. */ 63 if (stat(KERNEL_MAX, &buf) == 0) { 64 SAFE_FILE_SCANF(NULL, KERNEL_MAX, "%ld", &ncpus_max); 65 /* this is maximum CPU index allowed by the kernel 66 * configuration, so # of cpus allowed by config is +1 */ 67 ncpus_max++; 68 } else { 69 /* fall back to _SC_NPROCESSORS_CONF */ 70 ncpus_max = tst_ncpus_conf(); 71 } 72 return ncpus_max; 73 } 74
