[okl4-developer] How to garanty CPU isolation between cells ?

[Gernot Heiser]

>>>>> On Wed, 10 Dec 2008 13:51:54 +0100, Hugues Balp <hugues.balp at free.fr> said:
HB> Robert Wetzel wrote:

HB> I have performed the same test with a priority of 255 for the ok linux cell

HB> and a priority of 100 for the decrypt cell and the system doesnt' boot
HB> better...

You can't expect any system to work if you run apps (which is what OK
Linux is in this case) at the highest priority (higher than any
interrupt handlers, for example). I wouldn't expect anything to work
in such a setup.

Assignment of RT priorities is tricky, and your really need to
understand what you're doing (and there isn't really much helpful
theory). Which is a reason why we're trying to move away from
priority-based scheduling (see for example the work done at NICTA and
UCSC on using the RBED scheduler in L4). Unfortunately, most real-life
RT systems are based on priorities, so that's likely to remain the
default setup for a while...

Gernot