HTT/SMP

[Kris Kennaway]

On Mon, Feb 28, 2005 at 06:55:34PM -0600, Stephen Montgomery-Smith wrote:
> Kris Kennaway wrote:
> >On Mon, Feb 28, 2005 at 06:39:21PM -0600, Stephen Montgomery-Smith wrote:
> >
> >>I have a dual Xeon system, for which I had hyperthreading enabled.  I 
> >>was running a CPU intensive floating point program (specifically using 
> >>the fftw3 port with threads).  I found that using 4 (hyper) processors 
> >>really did give me a speed advantage, even though I do find web sites 
> >>that suggested this advantage was minimal.  (So for example, 4 processes 
> >>on this system seemed to run at the equivalent of 2GHz on these 3GHz 
> >>computers, so the advantage was about 1.3 times.)
> >>
> >>But then after about a day the computer had a panic.  I found that 4 
> >>CPU's under FreeBSD 5.3 is apparently unstable, and there were 
> >>statements to the effect that this would be fixed in FreeBSD 5.4.  Is 
> >>this going to happen?  I am currently running a rather recent version of 
> >>FreeBSD 5.3-Stable, maybe a week or two old, so I am concerned that 
> >>maybe this won't get committed.
> >
> >
> >Depends on the panic.  What was it?
> >
> >Kris
> 
> I'm sorry, but I didn't write it down.  Something about a page being 
> messed up or something.  Since I had already seen messages to the effect 
> that HTT on dual processors had problems, I assumed that it was just 
> that.

I run HTT on a dual processor machine and have not experienced
problems.

> I can tell you that I now have HTT disabled, and it is not 
> panicing at all.
> 
> Was there some fix committed (which would suggest that maybe this is 
> some other problem)?  If so, I could reenable HTT and wait for another 
> panic to occur, and then write it down.

You should set up crashdumps as described in the developers' handbook
and get a full trace.

Kris
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