Version 2.5.7

[lttng-ust.git] / libringbuffer / getcpu.h

diff --git a/libringbuffer/getcpu.h b/libringbuffer/getcpu.h
index f5f2f67571947b6c89d693ba8b9e28777f63cd89..190eae6c3d39bf131815e57b05c079c772ff103f 100644 (file)
--- a/libringbuffer/getcpu.h
+++ b/libringbuffer/getcpu.h
@@ -19,11 +19,9 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
-#define _GNU_SOURCE
 #include <urcu/compiler.h>
-#include <sched.h>
 
-#ifdef UST_VALGRIND
+#ifdef LTTNG_UST_DEBUG_VALGRIND
 
 /*
  * Fallback on cpu 0 if liblttng-ust is build with Valgrind support.
@@ -38,6 +36,33 @@ int lttng_ust_get_cpu(void)
 
 #else
 
+/*
+ * sched_getcpu.
+ */
+#ifdef __linux__
+
+/* old uClibc versions didn't have sched_getcpu */
+#if defined(__UCLIBC__) && __UCLIBC_MAJOR__ == 0 && \
+       (__UCLIBC_MINOR__ < 9 || \
+        (__UCLIBC_MINOR__ == 9 && __UCLIBC_SUBLEVEL__ <= 32))
+#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 cpu, ret;
+
+       ret = __getcpu(&cpu, NULL, NULL);
+       if (caa_unlikely(ret < 0))
+               return 0;
+       return c;
+}
+#else /* __UCLIBC__ */
+#include <sched.h>
+
 /*
  * If getcpu is not implemented in the kernel, use cpu 0 as fallback.
  */
@@ -51,6 +76,23 @@ int lttng_ust_get_cpu(void)
                return 0;
        return cpu;
 }
+#endif /* __UCLIBC__ */
+
+#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(void)
+{
+       return 0;
+}
+
+#else
+#error "Please add support for your OS into liblttng-ust/compat.h."
+#endif
 
 #endif