[uClinux-dev] Strict real timeness

[Leon Woestenberg]

Hello,

On 1/4/07, Preetam Joshi <j.preetam at gmail.com> wrote:
> I definitely need to implement applications which can follow real timeness.
> I have browsed throught the scheduler code and found that it implements
> tasks in a FIFO manner. So once the low priority thread runs the high
> priority thread does not preempt it until the timeslice of the low priority
> thread is over or any blocking call is explicitly called for. This certainly
> should not be the behavior.
>
You are not only concerned with scheduling properties when doing hard
real-time, but also with worst-case latency (which might also involve
solving priority inversion).

There are two approaches (AFAIK):
- Linux is run as a task within a real-time executive (RTAI, ...)
- give Linux real-time capabilities (Google for "linux-rt Ingo"). This
is work-in-progress.

Leon.