projects / lttng-ust.git / blame
| Commit | Line | Data |
|---|---|---|
| a6352fd4 | 1 | /* |
| 4318ae1b | 2 | * libringbuffer/smp.c |
| a6352fd4 | 3 | * |
| e92f3e28 | 4 | * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| a6352fd4 | 5 | * |
| e92f3e28 MD |
6 | * This library is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU Lesser General Public | |
| 8 | * License as published by the Free Software Foundation; only | |
| 9 | * version 2.1 of the License. | |
| 10 | * | |
| 11 | * This library is distributed in the hope that it will be useful, | |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 14 | * Lesser General Public License for more details. | |
| 15 | * | |
| 16 | * You should have received a copy of the GNU Lesser General Public | |
| 17 | * License along with this library; if not, write to the Free Software | |
| 18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
| a6352fd4 MD |
19 | */ |
| 20 | ||
| 5ad63a16 | 21 | #define _GNU_SOURCE |
| a6352fd4 | 22 | #include <unistd.h> |
| a6352fd4 MD |
23 | #include "usterr.h" |
| 24 | #include <pthread.h> | |
| 25 | #include "smp.h" | |
| 26 | ||
| 27 | int __num_possible_cpus; | |
| 28 | ||
| 29 | void _get_num_possible_cpus(void) | |
| 30 | { | |
| 31 | int result; | |
| 32 | ||
| 33 | /* On Linux, when some processors are offline | |
| 34 | * _SC_NPROCESSORS_CONF counts the offline | |
| 35 | * processors, whereas _SC_NPROCESSORS_ONLN | |
| 36 | * does not. If we used _SC_NPROCESSORS_ONLN, | |
| 37 | * getcpu() could return a value greater than | |
| 38 | * this sysconf, in which case the arrays | |
| 39 | * indexed by processor would overflow. | |
| 40 | */ | |
| 41 | result = sysconf(_SC_NPROCESSORS_CONF); | |
| 42 | if (result == -1) | |
| 43 | return; | |
| 44 | __num_possible_cpus = result; | |
| 45 | } |