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SubjectRe: real-time threaded IO with low latency (audio)
On Sun, Jul 25, 1999 at 08:20:06PM +0200, David Olofson wrote:
> > 3. any other trap or error condition that puts us in K mode.
>
> Does this need to be handled without losing the RT timing, or is it
> "just" a matter of handling it to keep RT an error condition from
> causing a bad crash?

Linux may die horribly if it allows the RT task to enter kernel mode.
So we would have to put guards on all kernel entry points
if running rt process (note current will not be useful)
then
call rt scheduler with error indication

the rt scheduler would then mark the current rt task with an error
condition and let it handle it. We'd bypass the linux scheduler entirely
and would have to add a RT call
run_user_mode_process(p);



Doesn't sound so bad now. A error would basically loose RT functionality: that seems
ok. But it would require a bigger Linux patch.


I described this idea to Linus and it made him deeply unhappy.




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