A method includes receiving a plurality of rules for processing packets arriving at at least one packet-processing device, the rules being based on multiple parameters associated with the packets. The method further includes causing the packet-processing device to process multiple subsets of the packets using different respective sequences of packet-processing instructions, which implement the rules via different respective parameter-value-ascertaining orders for ascertaining respective values of the parameters for each of the packets. The method further includes, based on the processing of the subsets, computing respective scores for the sequences of packet-processing instructions. The method further includes, based on the scores, selecting one of the sequences of packet-processing instructions. The method further includes causing the packet-processing device to process the packets using the selected sequence of packet-processing instructions. Other embodiments are also described.