[rescue] howto make multiple main boards work on a Sun Sparc 670/MP

[Dave McGuire]

On June 15, Kurt Mosiejczuk wrote:
> >   I will say that I'm very impressed with the performance of Linux on
> > SPARC hardware.  I wish they'd put the same amount of effort into
> > optimizing their Alpha support...it's just plain SLOW.  If they
> > address this, a DS10 or DS20 running Linux might very well be desktop
> > nirvana.
> >
> >   NO BASHING HERE, DAMMIT.
> 
> I seem to recall the reason for this being the amount of 64-bit unclean
> code that is out there.  I recall someone telling me that an Alpha
> running linux spends most of its time trapping invalid memory accesses
> and correcting them.  I suspect the only reason ultrasparc isn't bitten
> a LOT more by this is the 32-bit compatability.

  That would explain the performance issues I complained about.  An
unaligned access on an Alpha is a VERY expensive thing...I haven't
looked at it myself but I've heard other say that it sometimes costs
DOZENS of cycles of overheard.  It sounds like, if someone took a few
weeks and just went through everything for 64-bit cleanliness and
alignment, that performance problem might just go away.  That would
rock!

    -Dave McGuire