A request controller for controlling processing of requests by one or more semiconductor data processing unit. The resource controller includes a controller input for receiving a request for the processing unit to switch a context of the processing unit or to switch the processing unit from a current an operation to another operation. The resource controller includes a resource budget memory in which one or more budget value can be stored. The budget value represents an amount of a resource of the processing unit. The resource controller further has a budget controller which includes a first budget controller input connected to the request controller input. A second budget controller input is connected to the memory. A comparator is connected to the first budget controller input and the second controller input, for comparing a consumption value associated with the request with the budget value. The comparator includes a comparator output for outputting a request grant signal when the comparison satisfies a predetermined grant criterion and outputting a request reject value when the comparison meets a predetermined reject criterion. A data controller is connected to the resource budget memory and the comparator output, for adjusting the budget value when the request grant signal is outputted.