*/
#include <urcu/compiler.h>
-#include <sched.h>
+#include <urcu/system.h>
+#include <urcu/arch.h>
+
+void lttng_ust_getcpu_init(void);
+
+extern int (*lttng_get_cpu)(void);
-#ifdef UST_VALGRIND
+#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;
}
#else
+/*
+ * sched_getcpu.
+ */
+#ifdef __linux__
+
+#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 cpu;
+}
+#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_internal(void)
{
int cpu;
return 0;
return cpu;
}
+#endif /* HAVE_SCHED_GETCPU */
+
+#elif (defined(__FreeBSD__) || defined(__CYGWIN__))
+
+/*
+ * 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_internal(void)
+{
+ return 0;
+}
+
+#else
+#error "Please add support for your OS into liblttng-ust/compat.h."
+#endif
#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 */