Hmm, it's the Ethernet
12 root -68 - 0K 288K WAIT 2 0:37 5.66% {irq256: bge0}
What could this mean?
-----Original Message-----
Try pressing 'H' in top to see separate threads, this should give
you a hint who eats cpu. 8% system at 100r/s seems a bit too many
for me, too. But I really doubt it's nginx related.