Each /sys/class/net/<interface>/queues/tx-N directory has an xps_cpus file, which contains a bitmap of CPUs that can use the queue to transmit. In the following example transmit queue 0 can be used by the first two CPUs, and transmit queue 1 can be used by the following two CPUs:
# echo 3 > /sys/class/net/eth3/queues/tx-0/xps_cpus
# echo c > /sys/class/net/eth3/queues/tx-1/xps_cpusIf hyperthreading is enabled each hyperthread is identified as a separate CPU. For example if the system has 16 cores but 32 hyperthreads, then the transmit queues must be paired with the hyperthreaded cores:
# echo 30003 > /sys/class/net/eth3/queues/tx-0/xps_cpus
# echo c000c > /sys/class/net/eth3/queues/tx-1/xps_cpus