Implement THREAD_PRIORITY_TIME_CRITICAL

[Con Kolivas]

On Wednesday 05 April 2006 00:46, Andreas Mohr wrote:
> Hi,
>
> On Wed, Apr 05, 2006 at 12:36:06AM +1000, Con Kolivas wrote:
> > On Wednesday 05 April 2006 00:34, Andreas Mohr wrote:
> > > And this all should work perfectly well with NON-soft-realtime
> > > scheduling, as clearly said before.
> > > Well, in theory, at least...
> >
> > Andi just out of interest, how does normal scheduling on current ck
> > (2.6.16-ck3) perform with this?
>
> Hmm, difficult :-\
> I don't have any game candidate here, and frankly I don't even have a
> current Wine install...
>
> I'd think it's much easier for someone with such a Wine testcase to use a
> new kernel:
> - locate the .config file of the currently installed kernel package
> - get 2.6.16, patch to 2.6.16-ck3
> - run "make oldconfig" to answer all differences from current kernel
>   to 2.6.16-ck3 only
> - make bzImage modules modules_install
> - (update bootloader)
>
> About my sys call preemption latency rantings:
> It would be very useful to experiment with various CONFIG_PREEMPT settings
> here. And if some anomalies turn up, then it might be useful to add Ingo
> Molnar's latency tracing patch to a kernel and debug it further.

I don't think we're dealing with non preemptible sections of the kernel here 
so I doubt this will help.

> Stuff like that really shouldn't happen given that many people (among
> those also Windows core developers) say that our scheduling and thread
> creation performance usually beats Windows XP hands down.

This is not about speed, it's about scheduling order I'm almost certain. Don't 
forget that there are games on windows that stutter on audio if played on 
dual core hardware. That's an application design problem.

Cheers,
Con