VCL's OpenGLWrapper::getBufferSwapCounter() is useful to monitor how many frames are rendered on the screen / second. It would be useful to expose this in our UNO API as well.
Oh, it turns out 2c55288357c9d5410afae58c1fbb97cdfabf0360 even adds the UNO wrapper of master, so it would be only a matter of backporting the API to libreoffice-5-1.
Tor Lillqvist committed a patch related to this issue. It has been pushed to "libreoffice-5-1": http://cgit.freedesktop.org/libreoffice/core/commit/?id=59ebd032b834f31f2b3069395f7e7962a0adfea2&h=libreoffice-5-1 tdf#97633 Add API to get the number of OpenGL buffer swaps, including ... It will be available in 5.1.1. The patch should be included in the daily builds available at http://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More information about daily builds can be found at: http://wiki.documentfoundation.org/Testing_Daily_Builds Affected users are encouraged to test the fix and report feedback.