Here is a list of known bugs.

Slow kernel for CPU-intensive tasks
===================================

Although the included kernel performs  very well with low-latency  and
interactive  tasks, the scheduler seems to  behave very bad with tasks
which require intensive CPU usage (e.g. source code compilation).

If you need to run CPU-intensive tasks please issue them with:

nice -20 your_command

this will speed up the process by assigning it an high priority.