Re: RT patch acceptance

Ingo Molnar
2005-05-24T16:03:37Z

* Nick Piggin <nickpiggin@yahoo.com.au> wrote:

> Well, yes. There are lots of things Linux isn't suited for. There are
> likewise a lot of patches that SGI would love to get into the kernel
> so it runs better on their 500+ CPU systems. [...]

this reminds me. PREEMPT_RT found a handful of SMP races that not even
100+ CPU systems triggered in any deterministic way.

(I have mentioned this before but it seems worth repeating: the
preemption model of PREEMPT_RT is similar to a SMP Linux kernel running
on an system that has an 'infinite' number of CPUs. Each task can be
thought of having its own separate CPU - and SMP-alike instruction
overlap can happen at any instruction boundary.)

So the very small meets (and helps) the very large in interesting ways.
PREEMPT_RT very much depends on a good SMP implementation and on a good
CONFIG_PREEMPT implementation. The synergies are much wider than just
enabling deterministic behavior in embedded systems.

Ingo