scheduler (sched_4bsd) questions

[Peter Holm]

On Mon, Sep 27, 2004 at 10:52:16PM -0400, Stephan Uphoff wrote:
> On Sun, 2004-09-26 at 03:52, Peter Holm wrote:
> > On Sat, Sep 25, 2004 at 08:50:45PM -0700, Julian Elischer wrote:
> > > Stephan Uphoff wrote:
> > > 
> > > >>Maybe something brutal like:
> > > >>	if ((curthread->td_ksegrp == kg) &&
> > > >>	   (td->td_priority > curthread->td_priority))
> > > >>		curthread->td_flags |= TDF_NEEDRESCHED;
> > > >>
> > > >>in setrunqueue for
> > > >>the else case of "if (kg->kg_avail_opennings > 0)"
> > > >>would do the trick (without preemption) for the easy but probably more
> > > >>common cases?
> > > >>
> > > >>Maybe I can find some time next week to think about a clean
> > > >>fix. I find it always helpful having a small task in mind while reading
> > > >>source code.
> > > >
> > > >
> > > >I wrote a fix that should cover all cases.
> > > >However I would like to test it a little bit before posting the patch.
> > > >Is there any multi-threaded kernel torture program that you can
> > > >recommend?
> > > 
> > > 
> > > Peter Holm (CC'd) has a really cool set of torture tests.
> > > he has also seen all sorts of failures others have not (yet) triggered. :-)
> > > 
> > > I'm 'busy" for the next couple of weeks so you may want to communicate 
> > > directly with him and see if you and he together can figure out some of the 
> > > things he's
> > > been seeing :-)
> > > 
> > > his tests are at:
> > > http://www.holm.cc/stress/src/stress.tgz
> > > 
> > > >
> > > >Thanks
> > > >
> > > >	Stephan
> > > >
> > 
> > I'll be glad to test any patches.
> 
> Great.
> Can you try the attached patch to see if it changes any of your
> previously observed behaviour?
> 

The system still freezes and can be unfrozen by a ping:
http://www.holm.cc/stress/log/stephan.html

-- 
Peter Holm