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Re: MISC-d Digest V97 #28


On Thu, 24 Jul 1997, Eugene Leitl wrote:

> On Thu, 24 Jul 1997, Penio Penev wrote:
> 
> > On Thu, 24 Jul 1997, Eugene Leitl wrote:
> > [...]
> > If we agrre, that www.TheChipMerchant.com sells ar rock bottom prices, the
> > Cyrix 686 150MHz (200+) is  $83, which is is quite a few $10s.
> 
> I just bought a 166 K5, which was quite a number of $10. 83$ is perfecly 
> allright considering what an F21 is going to cost ($1? $10$ $40? I think 
> the latter).

I think somewhere between the former two.  More to the left side (in
QUANTITIES)


> > we are looking at:  K6-166-200-233 @ $181/233/400 ; 686MX-166/200 @
> > $177/249 ;  
> 
> Let's see what M2/K6/Pentium are going to cost in 3 months. 

Whatever the 686 was a few months ago -- $150 for a non-discontinued
product.

> Please notice 
> that a) I can't still buy an F21 (I've been waiting for them for almost 2 
> years now) b) the machine can run a lot of things the F21 can't do.

a) true.  And Jeff is hoping to change that soon :-)

b) not a Beaowulf pack.  You won't buy 100 workstations to run Excel.

> > > last
> > > time I looked MuP21 sold for roughly $40. 
> > 
> > This is to cover the development costs out of the sales of development
> > systems.  Do inquire about the price if you want to buy, say 10K MuP21. 
> 
> But I don't want to buy 10 k. I'd like to buy let's say 64 F21's, _with_ 
> a board, and SRAM. Besides of the fact that I can't buy them, I don't 
> think the prices will be that spectacular.

If you buy 64 Beaowulf nodes, you might as well buy 10K F21s (or at least
in that ball park).

> > > Motherboards cost next to
> > > nothing, 
> > 
> > Say, $150 form an MMX mb.  Source -- necxdirect.necx.com:8002
> 
> Who does need an MMX? Of what possible use is MMX in sci calculations, 
> unless one (oops) intends to do lattice algorithms?

The one that bought an MMX processor (remember, there is no vanilla Pentium
any more).  Anyway, the non-MMX ones are $110.

> > > and the rest of the components (RAM, HD, etc) are also needed for
> > > F21 nodes. 
> > 
> > I haven't heard of a Pentim running off 640K DRAM.  I've heard of Pentiums
> > running off 1M SRAM, though. (I've heard of R10Ks running of 4M SRAM :-) 
> 
> I need the RAM. 

You need a _total_ amount of RAM N MB.  Not a per-node constant, because
that depends on the number of nodes.  So, per node, the F21 will me much
cheaper, because it will be configured with less RAM.

> Wide RAM (64 bits).

10 F21s have a RAM bandwidth of 200 bits.  And can saturate it, I might
add.

> Fast RAM, preferably PB SRAM. 

What is the primary cache miss penalty for the Pentium?  What about the
secondary?  If you have 10--20 clocks latencies due to cache misses, what
good does it make to have memory with 1 versus 2 clocks latency?

> RAM 
> costs the same for F21 (I hope) as for a PC, and RAM usage is roughly the 
> same (code density plays no role in my application).

The total RAM for a given problem will be roughly the same for both.  For
a fraction of the price of the RAM, you'll have 1 F21 per 640K RAM.


> > > L3/L4 microkernel, a message-passing microkernal with Linux
> > > personality fits in 12 kBytes (i.e. in K6's cache). 
> > 
> > What abut the application and the FP code?  FP data?
> 
> Lots of lookups, vast amounts of data (16-64 MBytes), tiny code. I will 
> probably even use machine code, hideously ugly as Intel code is.

How about putting the code on-chip for F21?  No PCI chip set can beat F21
for lookups. 

> > May be, may be not.  But certainly 10xF21 will be better than 1xAMD.  And
> > about 10 time cheaper, I'd add. 
> 
> Let's see, I can get 100 F21's for one AMD (K5? K6? Whatever). Sold.
> Where can I get them, preferably without having to develop a host system
> from scratch (and also, not having to pay $50 for a meek piece of epoxy
> sans other semiconductors). 
>  
> > > Don't get me wrong, I still go for the F21. But it just doesn't compete 
> > > with the Beowulf, a different type of a beast entirely. 
> > 
> > The _only_ advantage of the Beowulf is that you can say 'make' and produce
> > something running on them.  The only. 
> 
> I don't see it quite like that.

You just contradicted that a few lines above -- "preferably ..."

> > In that regard the SuperDSP box is like the F21 -- porting is required.
> 
> Yeah, but you can get a QNX and a C compiler -- so porting cannot be 
> equaled to writing from scratch. (Fortunately, I don't need an OS for my 
> app).

You can get gnu c and compile to an intermediate code.  Then write a C
virtual machine for F21 and an F21/C front end for gcc -- that's trivial.
Your internal loops will be hand-coded anyway, if don't want to waste
money on hardware.


> > > However, beware of the Merced, which will be a C6x clone, and 
> > > run at 0.5-1 GHz).
> > 
> > Vaporware.
> 
> Merced, yes. 'C6x, no. ADSP-2106x, no. F21, yes. 

Merced is not coming out of the foundry in August, as far as I've heard.

The 'C6x is definitely a contender, but you'll need some pretty elaborate
tricks to squeeze the juice off it, and it is not good for table lookups.
And it costs $100 @ 10K

> Ask Analog for ADDS-2106X-EZ-LITE, what you get, and what does it cost. 
> (I'm still waiting for a 'C6x EV board TI was musing about some months ago). 

I believe TI is better than AMD.

> And never, never underestimate Intel.

As per Intel, do you know how much an embeddable 386 costs nowadays?  486? 

To summarize, I believe that for special purpose supercomputing, the MISC
approach will be 10 times the performance/price of the general purpose
approach.  I remains to be seen whether this is enough for somebody to
make money on that.

--
Penio Penev <Penev@pisa.Rockefeller.edu> 1-212-327-7423