Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!uwm.edu!lll-winken!vette!brooks
From: brooks@vette.llnl.gov (Eugene Brooks)
Newsgroups: comp.arch
Subject: Re: ATTACK OF KILLER MICROS (Actually parallel systems)
Message-ID: <36057@lll-winken.LLNL.GOV>
Date: 17 Oct 89 17:39:13 GMT
References: <35825@lll-winken.LLNL.GOV> <20336@princeton.Princeton.EDU>
Sender: usenet@lll-winken.LLNL.GOV
Reply-To: brooks@maddog.llnl.gov (Eugene Brooks)
Organization: Lawrence Livermore National Laboratory
Lines: 39

In article <20336@princeton.Princeton.EDU> mg@notecnirp.edu (Michael Golan) writes:
>1) There is no parallel machine currently the works faster than non-parallel
>machines for the same price. The "fastest" machines are also non-parallel - 
>these are vector processors.
This is false.  There are many counter examples for specific applications.


>2) A lot of research is going on - and went on for over 10 years now. As far
>as I know, no *really* scalable parallel architecture with shared memory exists
>that will scale far above 10 processors (i.e. 100). And it does not seems to
>me this will be possible in the near future.
Again, this is wrong.  Many scalable architectures exist in the literature
and some of them are well proven using simulation on real application codes.

>3) personally I feel parallel computing has no real future as the single cpu
>gets a 2-4 folds performance boost every few years, and parallel machines
>constructions just can't keep up with that. It seems to me that for at least 
>the next 10 years, non-parallel machines will still give the best performance 
>and the best performance/cost.
Massively parallel computing has a future because the performance increases
are 100 or 1000 fold.  I agree with the notion that using 2 processors, if
the software problems are severe, is not worth it because next years micro
will be twice as fast.  Next years supercomputer, however, will not be twice
as fast.

>4) I think Cray-like machines will be here for a long long time. People talk
>about Cray-sharing. This is true, but when an engineer needs a simulation to
>run and it takes 1 day each time, if you run it on a 2 or 3 day machine, he
>sits doing nothing for that time, which costs you a lot, i.e. it is turn-around
>time that really matters. And while computers get faster, its seems software
>complexity and the need for faster and faster machines is growing even more
>rapidly.
Cray like machines will be here for a long time indeed.  They will, however,
be implemented on single or nearly single chip microprocessors.  I do not
think that the "architecture" is bad, only the implementation has become
nearly obselete.  It is definitely obselete for scalar code and vectorized
code will follow within 5 years.

brooks@maddog.llnl.gov, brooks@maddog.uucp