Re: RT patch acceptance

[Karim Yaghmour <karim@opersys.com>]

[ removed a lot of interesting stuff ... ]

Andrea Arcangeli wrote:
> The point where preempt-RT enters the hard-RT equation, is only if you need
> syscall execution in realtime (like audio, but audio doesn't need
> hard-RT, so preempt-RT can only do good from an audio standpoint, it
> makes perfect sense that jack is used as argument for preempt-RT). If
> you need syscalls with hard-RT, the whole thing gets an order of
> magnitude more complicated and software becomes involved anyways, so
> then one can just hope that preempt-RT will get everything right and
> that somebody will demonstrate it.

Please have a look at RTAI-fusion. It provides deterministic
replacements for rt-able syscalls _transparently_ to STANDARD
Linux applications. For example, an unmodified Linux application
can get a deterministic nanosleep() via RTAI-fusion. The way
this works, is that rtai-fusion catches the syscalls prior to
them reaching Linux. So even the syscall thing isn't really a
limitation for RTAI anymore.

Philippe would be in a better position to elaborate, but that's
the essentials of it.

Karim
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