Aspects include monitoring a number of instructions of a first type dispatched to a first shared port of an issue queue of a processor and determining whether the number of instructions of the first type dispatched to the first shared port exceeds a port selection threshold. An instruction of a third type is dispatched to a second shared port of the issue queue associated with a plurality of instructions of a second type based on determining that the number of instructions of the first type dispatched to the first shared port exceeds the port selection threshold. The instruction of the third type is dispatched to the first shared port of the issue queue associated with a plurality of instructions of the first type based on determining that the number of instructions of the first type dispatched to the first shared port does not exceed the port selection threshold.