ELXSI System 6400 .... Information needed

[Josh Knight]

In article <120 at portal.UUcp> jel at portal.UUcp (John Little) writes:
>In article <1946 at calmasd.CALMA.UUCP>, rfc at calmasd.CALMA.UUCP (Robert Clayton) writes:
>> a 10 processor test at Sandia Labs they got 10.1X the power of a single
>> processor.  
>
>This is an interesting trick. Does anyone have a clue about how they
>got a greater than linear speedup?  Was this a cpu benchmark or did
>it include i/o?  Can I program my single processor to emulate a
>multiprocessor configuration and get increased performance :-) ?
>

We certainly don't have any of these things here, but I should think
that more processors might mean more memory.  On a time sharing workload,
more memory could mean better performance, enough to hide whatever extra
(if any) software cost was involved.  If you have 10 people editing
and 10 CPU's you may do many fewer context switches with concomittant
reduction software costs not to mention (perhaps) fewer cache misses.
There are lots of ways it COULD happen; however, like John, I'm a Little
(sorry John) skeptical.

Of course I don't speak for IBM, only me.
-- 

	Josh Knight, IBM T.J. Watson Research
 josh at ibm.com, josh at yktvmh.bitnet,  ...!philabs!polaris!josh