Re: RT patch acceptance

Thomas Gleixner
2005-05-27T10:17:36Z

On Fri, 2005-05-27 at 18:17 +1000, Nick Piggin wrote:
> >>Or have I missed something completely? You RT guys have thought about
> >>it - so what are some pros of the Linux-RT patch and/or cons of the
> >>nanokernel approach, please?
>
> I never saw it happen in this forum. I believe you if you say it
> has, but I suspect a lot has changed since then.

It happened and mostly ended with a flame feast.

I try to give a very short and incomplete answer to a complex question.

Having RT features integrated in the kernel itself makes it simple to do
smooth transitions of applications from the soft-RT to the hard-RT world
without changing code, recompiling. You have one set of libraries
instead of two and perfect collocation of non-RT and RT threads. Users
have only to deal with one API instead of two.

Nanokernels give you slightly better latencies and make a clear
seperation between the RT and non RT world. This seperation is better
reviewable and gives you a chance to do static code path analysis in
order to do theoretical worst case estimation, which is a prerequisite
for approvals in certain application fields.

Theres a lot more - factual and "religious", but it takes more than a
few lines and a few minutes :)

I think there will be more application areas than the unpopular
industrial/embedded stuff in the near future which would benefit from
integrated RT enhancements.

tglx