On Mon, Mar 3, 2008 at 2:01 PM, Robert F. Scheer <rfscheer at speakeasy.net>
wrote:

> Also, after installing the linux-rt ("realtime") kernel from Ubuntu
> repositories, the delay bag performance was horrible, as mentioned
> earlier, but not in the same league of hurt as the results you've just
> posted.
>


I can't tell if there's just the one real-time Linux which has multiple
names or if they're separate projects; I'm seeing linux-rt, Linux/RT,
rtlinux, RT-Linux, ...

Anyway, if they're all the same thing, then you're not using any of the
real-time features:

http://www.faqs.org/docs/Linux-HOWTO/RTLinux-HOWTO.html

In order to get real-time performance, it sounds like you need to write your
real-time code as a kernel module, and the rest of your application (the
parts that don't need to be real-time) would run in user-land and
communicate using a real-time FIFO character device.

Also, by real-time, they really do mean real-time: "Worst case interrupt
latency on a 486/33Mhz PC measures well under 30 microseconds, close to the
hardware limit." (ref:
http://www.linuxdevices.com/articles/AT3694406595.html, assuming it's the
same RT-Linux).

Gulik.

-- 
http://people.squeakfoundation.org/person/mikevdg
http://gulik.pbwiki.com/
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