implement ring buffer clients

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

diff --git a/include/ust/core.h b/include/ust/core.h
index 8c1c490eedde18b0615741ee1ec1a9773c0589ab..b9f5b9793887a27cb433444f26f8399f1ef60ca9 100644 (file)
--- a/include/ust/core.h
+++ b/include/ust/core.h
@@ -1,4 +1,8 @@
-/* Copyright (C) 2010  Pierre-Marc Fournier
+#ifndef UST_CORE_H
+#define UST_CORE_H
+
+/*
+ * Copyright (C) 2010  Pierre-Marc Fournier
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -15,11 +19,9 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  */
 
-#ifndef UST_CORE_H
-#define UST_CORE_H
-
 #include <sys/types.h>
 #include <ust/config.h>
+#include <urcu/arch.h>
 
 #define likely(x)      __builtin_expect(!!(x), 1)
 #define unlikely(x)    __builtin_expect(!!(x), 0)
@@ -136,4 +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 */