Control systems running on a computer are subject to timing disturbances coming from implementation constraints. Fortunately closed-loop systems behave robustly w.r.t. modelling errors and disturbances, and the controller design can be performed to explicitly enhance robustness against specific uncertainties. On one hand robustness in process controllers can be used to comply with weakly modelled timing uncertainties. On the other hand, the principle of robust closed-loop control can also be applied to the real-time scheduler to provide on-line adaption of some scheduling parameters, with the objective of controlling the computing resource allocation. As varying sampling appears to be a key actuator to control the computing resource, a varying sampling control design based on LPV gain scheduling design is provided. The feasibility of the approach is assessed through several examples using simulation and real experiments.