[nptl] Re: SCHED_RR issue

[Sebastien Decugis <sebastien.decugis@ext.bull.net>]

On Thu, 2004-09-16 at 10:43, Loic Domaigne wrote:
> Gidday! 
> 
> My answer took a bit time to come... I apologize for that.
> Hope that is was worth to wait 8-)

No problem :)

> 
> I have developped a program in order to understand what's going on. 
> After hours of testing (and constantly rebooting), I think I 
> finally extracted the core of the problem...
> 
> On my system, it seems that a SCHED_RR thread running at prio p+1 
> got sometimes troubles to start threads running at prio p!! 
> 
> I'll post the program on the forum ASAP. 
> People having access to SMP machines are urged to try it out ;-)

I can test on 2x and 8x IA32 with linux. I may also access IA64 and PPC
machines with linux. And also some AIX and Solaris boxes. But I don't
know the delays...


> I have also tested on an Alpha dual EV56 CPUs system. 
> Everything ran as expected. I couldn't reproduce the problem at all.
> Perhaps it is a Linux issue? 

That would be great -- meaning that we're right ;). In this case, the
problem is in the kernel... This might interest a lot of people I think.

> But we need:
> 1. gather more data.

I'll help ASAP.

> 2. verify that the program doesn't have any "BUG/RT-issue". 

Hard part here ^^' I'll have a look into your code but I am far from
being a RT expert :/

Thanks again,
Seb.

-------------------------------
Sebastien DECUGIS
NPTL Test & Trace Project
http://nptl.bullopensource.org/

"You may fail if you try.
You -will- fail if you don't."


Liste de diffusion nptl
Pour se désinscrire : mailto:nptl_request@bullopensource.org?subject=unsubscribe