Troubleshoot high interrupt on CPU

[Karli Sjöberg]

Hey all!

We´re experiencing intermittent "episodes" on especially one of our
storage servers, that CPU usage goes over 450%:

456.69% [intr]
RUN 90.97% [intr{irq265: ix0:que }]
CPU2 88.96% [intr{irq266: ix0:que }]
WAIT 55.96% [intr{irq268: ix0:que }]
RUN 52.98% [intr{irq267: ix0:que }]
WAIT 41.99% [intr{irq279: ix1:que }]
CPU5 37.99% [intr{irq278: ix1:que }]
WAIT 36.96% [intr{irq277: ix1:que }]
CPU3 25.98% [intr{irq276: ix1:que }]

So from this I´m thinking it´s something to do with the network, since
it´s ix interfaces. During these episodes network traffic goes down to
nil and clients loose contact, iSCSI-disks reconnects, directories can´t
open, music stops playing, etc. How can I debug this further? Is there
more information I can supply that would help you better understand the
situation?

/K