is a per-cpu kernel thread that runs when the machine is under heavy
soft-interrupt load. Soft interrupts are normally serviced on return from
a hard interrupt, but it's possible for soft interrupts to be triggered
more quickly than they can be serviced. If a soft interrupt is triggered
for a second time while soft interrupts are being handled, the
daemon is triggered to handle the soft interrupts in process context.
is taking more than a tiny percentage of CPU time, this indicates the
machine is under heavy soft interrupt load.
was introduced during the 2.3 development series as part of the
softnet work by Alexey Kuznetsov and David Miller.