Please look to one example of in efficient calculation of graph maximum value. In this particular case maximum value of plotted metric (avg. generation time) is 0.72 where maximum of graph is 2. I would say that is safe to scale maximum value with 1.0 to 1.1 and assume this as maximum value for graph. Of course on graphs with multiple metric plotted this is harder task. I think that on forum there has been proposal to introduce secondary axis to solve such kind of problems.

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