projects / lttng-ust.git / blame
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| 2b2d6ff7 MD |
1 | #ifndef _LTTNG_GETCPU_H |
| 2 | #define _LTTNG_GETCPU_H | |
| 3 | ||
| 4 | /* | |
| 5 | * Copyright (c) 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
| 6 | * | |
| 7 | * This library is free software; you can redistribute it and/or | |
| 8 | * modify it under the terms of the GNU Lesser General Public | |
| 9 | * License as published by the Free Software Foundation; only | |
| 10 | * version 2.1 of the License. | |
| 11 | * | |
| 12 | * This library is distributed in the hope that it will be useful, | |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 15 | * Lesser General Public License for more details. | |
| 16 | * | |
| 17 | * You should have received a copy of the GNU Lesser General Public | |
| 18 | * License along with this library; if not, write to the Free Software | |
| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
| 20 | */ | |
| 21 | ||
| 22 | #define _GNU_SOURCE | |
| 23 | #include <urcu/compiler.h> | |
| 24 | #include <sched.h> | |
| 25 | ||
| 26 | #ifdef UST_VALGRIND | |
| 27 | ||
| 28 | /* | |
| 29 | * Fallback on cpu 0 if liblttng-ust is build with Valgrind support. | |
| 30 | * get_cpu() returns the current CPU number. It may change due to | |
| 31 | * migration, so it is only statistically accurate. | |
| 32 | */ | |
| 33 | static inline | |
| 34 | int lttng_ust_get_cpu(void) | |
| 35 | { | |
| 36 | return 0; | |
| 37 | } | |
| 38 | ||
| 39 | #else | |
| 40 | ||
| 41 | /* | |
| 42 | * If getcpu is not implemented in the kernel, use cpu 0 as fallback. | |
| 43 | */ | |
| 44 | static inline | |
| 45 | int lttng_ust_get_cpu(void) | |
| 46 | { | |
| 47 | int cpu; | |
| 48 | ||
| 49 | cpu = sched_getcpu(); | |
| 50 | if (caa_unlikely(cpu < 0)) | |
| 51 | return 0; | |
| 52 | return cpu; | |
| 53 | } | |
| 54 | ||
| 55 | #endif | |
| 56 | ||
| 57 | #endif /* _LTTNG_GETCPU_H */ |