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Subject: Re: 64-way Parallel FP Chip

Author: Vincent Diepeveen

Date: 07:01:44 10/15/03

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On October 15, 2003 at 09:32:10, Robert Hyatt wrote:

>On October 14, 2003 at 17:29:18, Vincent Diepeveen wrote:
>
>>On October 14, 2003 at 16:18:28, Robert Hyatt wrote:
>>
>>>On October 14, 2003 at 14:29:36, Gerd Isenberg wrote:
>>>
>>>>On October 14, 2003 at 14:15:33, Vincent Diepeveen wrote:
>>>>
>>>>>On October 14, 2003 at 14:13:08, Gerd Isenberg wrote:
>>>>>
>>>>>>On October 14, 2003 at 10:07:10, Ricardo Gibert wrote:
>>>>>>
>>>>>>>
>>>>>>>http://www.wired.com/news/technology/0,1282,60791,00.html
>>>>>>>
>>>>>>>Can this be productively used in a chess program?
>>>>>>
>>>>>>I don't know, simular hardware ressources may be more productive for chess, if
>>>>>>implemented as hyperthreading devices. I guess it's a kind of further
>>>>>>development of SSE and AltiVec technology. With huge register files
>>>>>>(N * 64 * 64|128|256-bit?) and probably SIMD-wise integer instructions
>>>>>>(including popcount?) and fast memory interface, i can imagine that it is
>>>>>>usefull for a lot of nice things, like some eval passes, e.g. a first square
>>>>>>wise and a final scalar product pass. And fill-attack generation, e.g. square
>>>>>>wise in all 16 directions with a specialiced dumb fill routine.
>>>>>>
>>>>>>Gerd
>>>>>
>>>>>this is just floating point arrays.
>>>>
>>>>Aha, well may be a matter of interpretation.
>>>>I havn't seen any instruction set yet.
>>>>
>>>>On the other hand, if float and double arithmetic becomes as fast (or faster) as
>>>>integer, why not use it for eval purposes?
>>>>
>>>>Gerd
>>>
>>>
>>>Correct.  We did this on the Cray.  FP was very fast there and it frees
>>>up integer registers for addresses and array indices...
>>
>>That's of course true however at 16 processors of 100Mhz you reached 500k nodes
>>a second with cray blitz.
>>
>>Each Cray processor can issue up to 29 instructions a cycle.
>
>I have no idea what you are talking about.  Each cray processor can issue
>_one_ instruction per cycle.
>
>however, doing vector stuff, in one cycle the machine can do four memory
>reads and two memory writes (8 byte words) per processor.  It can also do
>multiple things in one cycle with vector chaining, but it never issues more
>than one instruction per cycle per cpu.
>
>I don't know what data you are looking at, but it is wrong.
>
>>
>>Crafty at a 1.6Ghz K7 which can issue up to 3 instructions a cycle gets 1
>>million nodes a second.
>>
>>So something capable of 100M * 16 * 29 = 46.4G instructions a cycle you get 500k
>>nps because it is a vector machine

Bob cut the crap.

If cray would execute 1 instruction a cycle then the processors would be
10 times slower than any other solution.

Yet everyone loves crays because they are vector processors which can do up to
29 instructions a cycle.

Even a P5/100 would have been faster than a cray because it can do 2
instructions a clock at 100Mhz.

You know that a cray can do 29 and i do. So cut this incredible nonsense right
here.

If you would have vectorized cray blitz correctly it would have run of course
faster than 500k nps. More like 5MLN nps at a 16 processor 100Mhz cray.

Thank you,
Vincent

>Again, you make up numbers that have nothing to do with reality.  A Cray
>can issue one instruction per cycle.  The C90 I used for the ICCA DTS
>article had a clock cycle time of 4.167 nanoseconds, the standard C90 clock
>speed.  That is about 250 million instructions per second per processor.  With
>16 processors, that is 4 billion, not your mythical 46.4 billion.  How about
>you start writing about things you know something about, and stop making stuff
>up about things you don't have a clue about?
>
>>
>>Something capable of 4.8G instructions a cycle you get 1 MLN nps because it is a
>>x86 processor.
>
>
>Pure garbage calculations don't convince anybody of anything.



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