[foxboard] ksoftirqd/0 using all cpu

[e_cocquerez]

Hi all,
When I execute "top" on the fow board, I see that "ksoftirqd/0" use
all cpu when one of my soft (using GPIO, 1wire and serial com) is running.
So, my question is : What do "ksoftirqd" ? 

Bests regards
Eric