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.

server/core/maxscale/statistics.h

@@ -0,0 +1,37 @@
+#pragma once
+/*
+ * Copyright (c) 2016 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl.
+ *
+ * Change Date: 2019-07-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+/**
+ * @file
+ *
+ * Internal code for the statistics system.
+ */
+
+#include <maxscale/statistics.h>
+
+MXS_BEGIN_DECLS
+
+/**
+ * @brief Initialize statistics system
+ *
+ * This function should only be called once by the MaxScale core.
+ */
+void ts_stats_init();
+
+/**
+ * @brief Terminate statistics system
+ */
+void ts_stats_end();
+
+MXS_END_DECLS