That's a separate issue from BH processing, though.
> 2. You often have woken a task but dont want it to leap into life
> instantly
I've recently looked at this, and if you wake an RT process then
current->need_resched is set to 1 anyway. Same story if the woken
process has a higher dynamic priority than current.
So in fact you can't avoid the context switch anyway.
> > >From looking at the current Linux capabilities, it looks to me like we
> > can indeed give hard-RT performance. Sure, it may mean not using
> > broken 8390 drivers which globally disable interrupts while spending
> > 1.6 ms reading a packet, but hey, we can live with that ;-)
>
> I've been working on two things where hard real time is an important
> matter. That is localtalk cards and dumb synchronous cards. The former
> requires I hit 90uS or so worst case latency on receive, the latter to
> do 2Mbits is even tighter.
>
> > Being able to do all this with normal Linux without having to resort
> > to RTLinux is a goal worthy of pursuit.
>
> No argument ;)
:-)
Regards,
Richard....
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