-#ifndef _LTTNG_GETCPU_H
-#define _LTTNG_GETCPU_H
-
/*
- * Copyright (c) 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * SPDX-License-Identifier: LGPL-2.1-only
*
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; only
- * version 2.1 of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*/
+#ifndef _LTTNG_GETCPU_H
+#define _LTTNG_GETCPU_H
+
#include <urcu/compiler.h>
+#include <urcu/system.h>
+#include <urcu/arch.h>
+
+void lttng_ust_getcpu_init(void);
-#ifdef UST_VALGRIND
+extern int (*lttng_get_cpu)(void);
+
+#ifdef LTTNG_UST_DEBUG_VALGRIND
/*
* Fallback on cpu 0 if liblttng-ust is build with Valgrind support.
* migration, so it is only statistically accurate.
*/
static inline
-int lttng_ust_get_cpu(void)
+int lttng_ust_get_cpu_internal(void)
{
return 0;
}
*/
#ifdef __linux__
-#ifdef __UCLIBC__
+#if !HAVE_SCHED_GETCPU
#include <sys/syscall.h>
#define __getcpu(cpu, node, cache) syscall(__NR_getcpu, cpu, node, cache)
/*
* If getcpu is not implemented in the kernel, use cpu 0 as fallback.
*/
static inline
-int lttng_ust_get_cpu(void)
+int lttng_ust_get_cpu_internal(void)
{
int cpu, ret;
ret = __getcpu(&cpu, NULL, NULL);
if (caa_unlikely(ret < 0))
return 0;
- return c;
+ return cpu;
}
-#else /* __UCLIBC__ */
+#else /* HAVE_SCHED_GETCPU */
#include <sched.h>
/*
* If getcpu is not implemented in the kernel, use cpu 0 as fallback.
*/
static inline
-int lttng_ust_get_cpu(void)
+int lttng_ust_get_cpu_internal(void)
{
int cpu;
return 0;
return cpu;
}
-#endif /* __UCLIBC__ */
+#endif /* HAVE_SCHED_GETCPU */
-#elif defined(__FreeBSD__)
+#elif (defined(__FreeBSD__) || defined(__CYGWIN__))
/*
- * FreeBSD does not allow query of CPU ID. Always use CPU number 0, with
- * the assocated performance degradation on SMP.
+ * FreeBSD and Cygwin do not allow query of CPU ID. Always use CPU
+ * number 0, with the assocated performance degradation on SMP.
*/
static inline
-int lttng_ust_get_cpu(void)
+int lttng_ust_get_cpu_internal(void)
{
return 0;
}
#endif
+static inline
+int lttng_ust_get_cpu(void)
+{
+ int (*getcpu)(void) = CMM_LOAD_SHARED(lttng_get_cpu);
+
+ if (caa_likely(!getcpu)) {
+ return lttng_ust_get_cpu_internal();
+ } else {
+ return getcpu();
+ }
+}
+
#endif /* _LTTNG_GETCPU_H */