> we can resurrect the discontinued rescheduling interrupt for this, whee.
or better, this color map should be mcount() driven. Instead of
interrupting the other CPU, we can simply read the last mcount() EIP
value, and use that as an index into the color map. (we do this only if we
are in an interrupt handler).
this way we have an exact picture about which IRQ handler executes the
same time as an arbitrary kernel-function.
-- mingo