X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=libringbuffer%2Fgetcpu.h;h=fbddb7989336b71235ba238eff9ae860c41a3d6e;hb=03edf5f6766b95cf1cbc0b4712bc7b70c153e16a;hp=3474bfe0c04f9f218eac190b001b08600f9d8272;hpb=c993aa602df5d770ea1da811c4f7f643dde1ed34;p=lttng-ust.git

diff --git a/libringbuffer/getcpu.h b/libringbuffer/getcpu.h
index 3474bfe0..fbddb798 100644
--- a/libringbuffer/getcpu.h
+++ b/libringbuffer/getcpu.h
@@ -20,8 +20,14 @@
  */
 
 #include <urcu/compiler.h>
+#include <urcu/system.h>
+#include <urcu/arch.h>
 
-#ifdef UST_VALGRIND
+void lttng_ust_getcpu_init(void);
+
+extern int (*lttng_get_cpu)(void);
+
+#ifdef LTTNG_UST_DEBUG_VALGRIND
 
 /*
  * Fallback on cpu 0 if liblttng-ust is build with Valgrind support.
@@ -29,7 +35,7 @@
  * migration, so it is only statistically accurate.
  */
 static inline
-int lttng_ust_get_cpu(void)
+int lttng_ust_get_cpu_internal(void)
 {
 	return 0;
 }
@@ -41,14 +47,17 @@ int lttng_ust_get_cpu(void)
  */
 #ifdef __linux__
 
-#ifdef __UCLIBC__
+/* 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 lttng_ust_get_cpu_internal(void)
 {
 	int cpu, ret;
 
@@ -64,7 +73,7 @@ int lttng_ust_get_cpu(void)
  * 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;
 
@@ -75,14 +84,14 @@ int lttng_ust_get_cpu(void)
 }
 #endif	/* __UCLIBC__ */
 
-#elif defined(__FreeBSD__)
+#elif (defined(__FreeBSD__) || defined(__CYGWIN__))
 
 /*
- * FreeBSD does not allow query of CPU ID. Always use CPU number 0, with
- * the assocated performance degradation on SMP.
+ * 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)
+int lttng_ust_get_cpu_internal(void)
 {
 	return 0;
 }
@@ -93,4 +102,16 @@ int lttng_ust_get_cpu(void)
 
 #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 */