Teartest with -o flag to specify override redirect window and -r number to specify refresh rate.

client/deps/glbench/src/glx_stuff.cc

 // Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <string.h>
 
 #include "main.h"
 #include "xlib_window.h"
 
 GLXContext glx_context = NULL;
@@ skipping 51 matching lines @@
 }
 
 void DestroyContext() {
   glXMakeCurrent(xlib_display, 0, NULL);
   glXDestroyContext(xlib_display, glx_context);
 }
 
 void SwapBuffers() {
   glXSwapBuffers(xlib_display, xlib_window);
 }
+
+bool SwapInterval(int interval) {
+  return glXSwapIntervalSGI(interval) == 0;
+}