Apparatus for communications includes a CPU, a system memory, and a network interface controller (NIC), which is configured to receive incoming data packets from a network, to post the received data packets in a designated queue for delivery to the CPU. The NIC issues interrupts to the CPU in response to the incoming data packets at a rate determined, for the designated queue, in accordance with an interrupt moderation parameter that is set for the queue. During each of a succession of monitoring periods, the CPU measures for the designated queue a current throughput of the incoming data packets and a current rate of interrupts, makes a comparison between the current measured throughput and rate of interrupts to the throughput and rate of interrupts that were measured during a preceding period in the succession, and selects and applies an update to the interrupt moderation parameter responsively to the comparison.