Hi,
No it is not possible for acados to know beforehand how long an SQP iteration will take on a specific hardware and for a specific problem.
However, if one uses RTI, i.e. a single linearization and a single QP solve, the CPU time should be pretty deterministic.
You can additionally limit the number of QP solver iterations.
Those are definitely relevant questions for MPC practice that are not trivial to answer in general.
Best,
Jonathan