One difference to your tests seems to be that I did not ran my tests with a single user.
I cannot predict the outcome with more users , but I do not exclude any possibility that effect of a CPU cache miss would be more visible with multiuser load.
That 5.3 would behave any better on this simplistic load, is rather unintuitive, to my knowlegde there were no performance-relevant patches affecting this load in between 5.2 and 5.3
One difference to your tests seems to be that I did not ran my tests with a single user. relevant patches affecting this load in between 5.2 and 5.3
I cannot predict the outcome with more users , but I do not exclude any possibility that effect of a CPU cache miss would be more visible with multiuser load.
That 5.3 would behave any better on this simplistic load, is rather unintuitive, to my knowlegde there were no performance-