2004-04-16 08:20:59

by abhinav singh

Subject: How-to write soft real-time programs Kernel-2.6.x

i m a relatively newbie to kernel-2.6.x. But i have
information that suggests that kernel-2.6.x has got
soft real-time capabilities.

So how-to write a simple program(may be a Hello world
program) which has real-time capabilities. I require
it for writing a program on kernel-2.6.x that uses the
soft real-time capabilities.

Any help in this matter will be highly appreciated.

Abhinav.





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2004-04-16 10:04:10

by Axel Weiss

Subject: Re: How-to write soft real-time programs Kernel-2.6.x

Am Freitag, 16. April 2004 10:20 schrieb abhinav singh:
> i m a relatively newbie to kernel-2.6.x. But i have
> information that suggests that kernel-2.6.x has got
> soft real-time capabilities.
>
> So how-to write a simple program(may be a Hello world
> program) which has real-time capabilities. I require
> it for writing a program on kernel-2.6.x that uses the
> soft real-time capabilities.
Are you looking for http://www.rtai.org ?

Regards,
Axel

2004-04-16 13:18:13

by Chris Friesen

Subject: Re: How-to write soft real-time programs Kernel-2.6.x

abhinav singh wrote:

> So how-to write a simple program(may be a Hello world
> program) which has real-time capabilities.


Something like the following will put you into one of the "realtime"
scheduling classes, and you will take priority over the normally
scheduled tasks.


struct sched_param p;
p.sched_priority=50;
if (sched_setscheduler(getpid(), SCHED_RR, &p) < 0) {
perror("error while setting scheduler class");
printf("continuing anyways, but results may not be as good\n");
}


The whole issue of soft-realtime is a complicated one, and there are
many other things that should be done to maximise predictability.


Chris