RE: SMP scalability: 8 -> 32 CPUs

Rik van Riel (H.H.vanRiel@phys.uu.nl)
Mon, 30 Nov 1998 13:50:02 +0100 (CET)


On Fri, 27 Nov 1998, Dave Wreski wrote:
> On 28-Nov-98 Eloy A. Paris wrote:
> > Guys, excuse my ignorance, but does anyone know why Linus said in his
> > last Linux Journal interview that right now it is fairly unrealistic
> > to expect scaling from 8 to 32 CPUs? What's stopping Linux to scale in
> > terms of CPUs?
>
> 1. Because there aren't many PCs with 8 or more CPUs around to do
> testing on.
> 2. Because of #1, our efforts are better spent working on more
> real-life problems.

Number 2 is the most important reason. Just look at the
Linux-MM site (on my home page) to get an impression on
the average TODO list each subsystem has.

Linux is coded mostly by volunteers who prefer to think
up code which is either interesting/sexy or which has
an impact on performance on his/her _own_ machine.

While the 8+CPU scalability definately _is_ a sexy thing
to code up (I might get around to the scheduling side of
things :) I don't know of anyone with a real machine who
can benefit from this situation.

That, of course, will change when someone donates one of
those old 8-CPU [34]86 SMP machines from Compaq or Sequent
to one of the scheduler hackers :)) <hint, hint>

cheers,

Rik -- now completely used to dvorak kbd layout...
+-------------------------------------------------------------------+
| Linux memory management tour guide. H.H.vanRiel@phys.uu.nl |
| Scouting Vries cubscout leader. http://www.phys.uu.nl/~riel/ |
+-------------------------------------------------------------------+

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/