In one embodiment, a first computing device determines a number of data packets available to transmit from the first computing device to a second computing device. The determination is based on an available bandwidth and a payload capacity, and each of the data packets has a payload with the payload capacity. The first computing device determines a plurality of data items to transmit from the first computing device to the second computing device. The first computing device then ranks the data items and selects, based at least in part on the ranking of the data items and the payload capacities of the data packets, one or more particular ones of the data items to transmit from the first computing device to the second computing device in the data packets. The first computing device writes the particular ones of the data items to the payloads of the data packets.