Align statistics to cache lines

Aligning the statistics object indices to cache line size reduces the CPU
overhead of gathering the statistics. This allows the statistics to more
accurately measure the polling system without the measurement affecting
the outcome.

include/maxscale/utils.h

@@ -37,6 +37,12 @@ MXS_BEGIN_DECLS
 
 #define MXS_ARRAY_NELEMS(array) ((size_t)(sizeof(array)/sizeof(array[0])))
 
+/** Macro for safe pointer arithmetic on void pointers
+ * @param a The void pointer
+ * @param b The offset into @c a
+ */
+#define MXS_PTR(a, b) (((uint8_t*)(a)) + (b))
+
 bool utils_init(); /*< Call this first before using any other function */
 void utils_end();