implement ring buffer clients

[lttng-ust.git] / include / ust / core.h

diff --git a/include/ust/core.h b/include/ust/core.h
index d1fdb2dfdb2c7faa9eb6805a37b6f99bace22a22..b9f5b9793887a27cb433444f26f8399f1ef60ca9 100644 (file)
--- a/include/ust/core.h
+++ b/include/ust/core.h
@@ -138,4 +138,35 @@ static __inline__ int get_count_order(unsigned int count)
 #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
 #endif
 
+#ifndef UST_VALGRIND
+
+static __inline__ int ust_get_cpu(void)
+{
+       int cpu;
+
+       cpu = sched_getcpu();
+       if (likely(cpu >= 0))
+               return cpu;
+       /*
+        * If getcpu(2) is not implemented in the Kernel use CPU 0 as fallback.
+        */
+       return 0;
+}
+
+#else  /* #else #ifndef UST_VALGRIND */
+
+static __inline__ int ust_get_cpu(void)
+{
+       /*
+        * Valgrind does not support the sched_getcpu() vsyscall.
+        * It causes it to detect a segfault in the program and stop it.
+        * So if we want to check libust with valgrind, we have to refrain
+        * from using this call. TODO: it would probably be better to return
+        * other values too, to better test it.
+        */
+       return 0;
+}
+
+#endif /* #else #ifndef UST_VALGRIND */
+
 #endif /* UST_CORE_H */