Why not starting with frames per second?

This is a good question with lots of possible answers.

A good place to start in measuring the performance of algorithms in augmented reality is

https://www.researchgate.net/publication/266097617_EKF_Monocular_SLAM_3D_Modeling_Measuring_and_Augmented_Reality_from_Endoscope_Image_Sequences

and

https://www.researchgate.net/publication/282374362_Machine_learning_schemes_in_augmented_reality_for_features_detection

More to the point, see, for example:

https://www.researchgate.net/publication/282374362_Machine_learning_schemes_in_augmented_reality_for_features_detection

and

https://www.researchgate.net/publication/49675711_Extended_Keyframe_Detection_with_Stable_Tracking_for_Multiple_3D_Object_Tracking/figures?lo=1

Article EKF Monocular SLAM 3D Modeling, Measuring and Augmented Real...

Article Machine learning schemes in augmented reality for features detection

Article Extended Keyframe Detection with Stable Tracking for Multipl...

If the algorithm for a particular program is running in a synchronized thread, then you can time how long that thread runs for.

Thanks Daniel, Lior and James. I have to take a look to the papers of James, surely they perform experiments that perhaps help me.

Best,

Jose