Add freebsd support for getcpu (use cpu nr 0)

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

diff --git a/libringbuffer/getcpu.h b/libringbuffer/getcpu.h
index 44d0d5594f04641029bb70116d6784b8f8ef0ff0..0a61941728a5de814ca5e5339d30fa945d3ed9fc 100644 (file)
--- a/libringbuffer/getcpu.h
+++ b/libringbuffer/getcpu.h
@@ -20,7 +20,6 @@
  */
 
 #include <urcu/compiler.h>
-#include <sched.h>
 
 #ifdef LTTNG_UST_DEBUG_VALGRIND
 
@@ -37,6 +36,30 @@ int lttng_ust_get_cpu(void)
 
 #else
 
+/*
+ * sched_getcpu.
+ */
+#ifdef __linux__
+
+#ifdef __UCLIBC__
+#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.
  */
@@ -50,6 +73,23 @@ int lttng_ust_get_cpu(void)
                return 0;
        return cpu;
 }
+#endif /* __UCLIBC__ */
+
+#elif defined(__FreeBSD__)
+
+/*
+ * FreeBSD does 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