Approaches to realtime Linux
Posted Oct 12, 2004 22:08 UTC (Tue) by simlo
In reply to: Approaches to realtime Linux
Parent article: Approaches to realtime Linux
Now due to this splindid article here at LWN I downloaded the latests version of RTAI and started to look at it. If it lives up to it's promises it is really great!
However, isn't Adeos/RTAI adding just an extra level of locking just as MontaVista's patch? And on top of that an extra scheduler is added!?
RTAI does sound like a more expensive solution to me. If the goal was to seperate the real time threads and the none real time threads having two different schedulers is a splindid idea. But RTAI want to make it look the same towards the programmer. I am afraid the coder will make the mitake of calling Linux system calls and break the real time behaviour of the system.
Making all these system calls unavailable from real time part would make more sense - and could justify having two scheduleres on the system. But if you want to make the systems look the same it sounds more like a temporarely solution.
Another problem is device drivers: You can't use the device drivers from normal Linux in you real time subsystem (I briefly looked at the RT-net project who have made seperate device drivers). With the idea of making Linux itself real time you can - but you might have to rewrite some to make them perform better wrt. latencies and prioritising access.
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