Explanation of roofline model I am currently studying the roofline model. Wikipedia [2] shows the following example graph:

The diagonal line shows $\beta * I$. But I do not understand why this line does not go through the zero point. If $I = 0$ so should $\beta * I = 0$. What am I misunderstanding here?
[2] https://en.wikipedia.org/wiki/Roofline_model
The axes are in logarithmic scale, and so don't really have a zero point. What you are seeing is
$$ \log P = \min(\log I + \log \beta, \log \pi). $$
The striking part is that the slope of the line is always the same.