🚀 go-pugleaf

In article <788@stat.fsu.edu> I wrote:
>So applying some scaling suggests that a 4-cpu Cray Y/MP at 6 ns will
>be about 290 times as fast as the R-3000 box.  Then scale the MIPS cpu....

To which brooks@maddog.llnl.gov (Eugene Brooks) replied:
>So to really compare one processor to one processor, as any reasonable person
                                                      ^^^^^^^^^^^^^^^^^^^^^^^^
>would do, we divide the 290 by 4 to get a ratio of 72 for the 6 NS Y to the
 ^^^^^^^^
>R3000. [...details deleted...] you get a factor of 29 for the YMP vs the R6000.

So, I am not a reasonable person?  I compared a configuration of the
Cray which is _smaller_ than the one I ran on with the only
configuration of the MIPS product that I have even heard of.  The MIPS
is not even announced yet as a single-processor, so it is giving a
slight advantage to the killer micro, since it is comparing a delivered
system to an unannounced one....

Maybe I should use single-cpu performance comparisons with my Connection
Machine results? :-)


>The bottom line, roughly 30 times the speed for 30 times
>the cost for code which is fully vectorized on the Y.  There is an absolute
>performance advantage but no cost-performance advantage.

If the MIPS box had enough memory and disk to run the same jobs that I
run on the Cray, then the Cray should be about 2 times more
cost-effective in that naive measure.  Of course if I have a job that
takes 100 hours on an 8-processor Y/MP, then I would have to wait for
59 weeks on the (almost) equally cost-effective "KILLER MICRO from
HELL".

>If your code is not 99% vectorized, however, you are very foolish to run
>it on a traditional supercomputer cpu.  As you correctly point out.

Well, I didn't say "very foolish", but as a taxpayer I would prefer
people to use the more expensive of the government-owned machines only for
jobs that they are reasonably cost-effective for....


I wrote:
>This is all just as excuse to remind Eugene :-) that some users will
>still be able to make effective use of vector supercomputers.  In

Eugene replied:
>I pointed out in my posting that Killer Micros have overrun traditional
>supercomputers in scalar performance.  I qualified this very explicitly
>in my posting.  The notion that I need to be reminded that traditional
>supercomputers are still hanging in there for codes which are nearly 100%
>vectorized is silly.
>brooks@maddog.llnl.gov, brooks@maddog.uucp

That's what the smiley face was there for....

By the way, the most cost-effective machine on my code is the new
Stardent 3000.  It runs at about 1/15 of the speed of the Cray on a
per-cpu basis and is less than 1/50 of the cost....  Too bad I can't
afford one!