Just happened again, with DNSPrivacy disabled. Looks like the missing cpu is showing as io. Any way to get more details on that?
Here's the full top output:
Mem: 873288K used, 30284K free, 32K shrd, 160K buff, 3672K cached
CPU: 0.0% usr 1.9% sys 0.0% nic 63.5% idle 34.4% io 0.0% irq 0.0%...