1. A data processing system comprising: a first processor implementing a plurality of computational nodes, each node performing a corresponding operation in a data flow for data received at that node; and a second special-purpose processor, wherein the first processor and second special-purpose processor are configured to: determine, via the first processor, a compression benefit metric pertaining to performance of the corresponding operations of one or more of said plurality of computational nodes in the data flow with recompressed data, wherein the first processor is configured to determine a priority for recompressing data based on the compression benefit metric; recompress the data according to the priority, via the second special-purpose processor, for processing by the one or more computational nodes in the data flow based on the compression benefit metric indicating a benefit in processing performance gained by using the recompressed data for computational operations; and perform the corresponding operation using the recompressed data, via the first processor, to provide the benefit in processing performance.