Re: [RFC][PATCH] Restricted hard realtime

[Ingo Molnar <mingo@elte.hu>]

* Jon Masters <jonathan@jonmasters.org> wrote:

> I guess it would. But then we've just had a slew of RT implementations
> crawl out of the woodwork and wave at us over the past few weeks and
> there are three other major RT implementations which combine Linux
> with a Microkernel or other external support (RTLinux, RTAI, KURT,
> etc.). Perhaps it's worth working on one of the Linux patch projects
> (Monta/Ingo/etc.) rather than going all out to implement it all again.

also note that (as i mentioned it in an earlier reply to Paul) the
'CPU[s] isolated for hard-RT use' scheduler feature has already been
implemented by Dimitri Sivanich and was accepted and integrated into the
2.6.9 kernel a couple of weeks ago.

Isolated CPUs can be set up via the "isolcpus=" boot parameter, and can
be entered via the affinity syscall. The feature came with related fixes
to the scheduler and other kernel code to eliminate cross-effects
between domains. (such as the scheduler balancing code, or the swap
tick)

So this all is banging on open doors, this particular mode of hard-RT
scheduling is there and available in vanilla Linux. If anyone wants to
try it, just download 2.6.9 and use it.

	Ingo