I have a Real-Time program that I'm porting from DOS/AMX to RTLinux which is
a mixture of hard and soft real-time components. The hard real-time tasks
service the private (MIL-1553B) network , the network messages and
miscellaneous hardware peripherals while the soft real-time tasks manage the
display. We did -- in AMX -- prioritize the message-handling tasks because
they were (pseudo) soft [i.e. nobody would notice an occasional lapse] while
most of the display ran in a prioritized background.
Obviously we can translate the ISR's directly into device drivers and the
display tasks into "normal" UNIX prioritized tasks, but what's the best way
to handle what are the currently prioritized message and hardware-handling
tasks? We can't guarantee timely completion every time because the running
time is (partially) data-dependent, but we know from years of experience
that on the average we're >99% timely completion. We do feel that we'd like
to maintain the prioritized nature of these tasks Is there any way within
RTLinux to prioritize real-time tasks?
Norm
> -----Original Message-----
>
> Avoid the use of priority if at all possible, and if needed use it as
> little as possible. Instead, have your tasks designed so they have
> well defined completion time bounds (or time bounds for time to yield
> the CPU to other tasks).
>
> One of the nasty ways systems can fail is that they work fine until
> presented with a very high load, at which point critical things don't
> get done anymore because other things were given higher priority and
> they now consume 100% of the CPU. If you don't use priority and your
> tasks all have time bounds, this failure cannot happen, and your
> system is stable under all loads.
>
> To put it differently: if you use priority, it is far harder to prove
> liveness and time bounds for any tasks other than the subset that uses
> the highest priority. (And if you use interrupts, it gets even
> harder.)
>
>
--- [rtl] ---
To unsubscribe:
echo "unsubscribe rtl" | mail [EMAIL PROTECTED] OR
echo "unsubscribe rtl <Your_email>" | mail [EMAIL PROTECTED]
----
For more information on Real-Time Linux see:
http://www.rtlinux.org/~rtlinux/
