1 files changed, 34 insertions, 0 deletions
diff --git a/benchtests/bench-util.c b/benchtests/bench-util.c
new file mode 100644
index 0000000..c4149ae
--- /dev/null
+++ b/benchtests/bench-util.c
@@ -0,0 +1,34 @@
+/* Benchmark utility functions.
+   Copyright (C) 2015 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+
+static volatile unsigned int dontoptimize = 0;
+
+void
+bench_start (void)
+{
+  /* This loop should cause CPU to switch to maximal freqency.
+     This makes subsequent measurement more accurate.  We need a side effect
+     to prevent the loop being deleted by compiler.
+     This should be enough to cause CPU to speed up and it is simpler than
+     running loop for constant time.  This is used when user does not have root
+     access to set a constant freqency.  */
+
+  for (int k = 0; k < START_ITER; k++)
+    dontoptimize += 23 * dontoptimize + 2;
+}