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Subject: Re: HW based Crafty (Boule's thesis)

Author: Robert Hyatt

Date: 19:31:21 04/03/02

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On April 03, 2002 at 19:15:20, Keith Evans wrote:

>On April 03, 2002 at 17:49:58, Robert Hyatt wrote:
>
>>On April 03, 2002 at 15:41:31, Tom Kerrigan wrote:
>>
>>>On April 03, 2002 at 11:44:45, Robert Hyatt wrote:
>>>
>>>>Again this depends on the FPGA you are looking at.  DB processors ran at
>>>>20-24mhz, and searched at 2M-2.4M nodes per second each.  Hsu later reported
>>>>that at least a factor of 15 speed-up would be possible with newer fab
>>>>processes.  He predicted 36M for .18u as a first guess...
>>>
>>>Uhhhh, are you clear on what an FPGA is? DB had absolutely nothing to do with
>>>FPGAs in any way, shape, or form. You're comparing a motorcycle to a paddle
>>>boat, and I'm not even sure what conclusions you're trying to draw from that
>>>comparison.
>>
>>
>>Yes I am aware of what an FPGA is.  I believe that a SOTA (state of the art)
>>fpga can run just as fast as the 3 micron (three micron, not .3) micron process
>>ASICS used in the original DB hardware...  3 micron ASICS in DB only ran at
>>24mhz.  An FPGA can certainly be run at that clock speed...
>>
>
>Actually.....
>
>From the IEEE micro article:
>
>"The chess chips in 0.6-micron CMOS searched 2 to 2.5 million chess positions
>per second per chip." Capable of a 40 ns cycle time at best.
>
>So we're comparing:
>
>   a full custom 0.6-micron, three-metal layer 5-V CMOS chip
>                 ^^^^^^^^^^  ^^^^^^^^^^^^^^^^^
>   with



Aren't you switching to _deep blue 2_ now?  I think I have something somewhere
that says that either the deep thought or deep blue 1 hardware was 3 micron,
I'll look it up when I hit the office.  I think the IEE article was about DB2
but again, I am not certain without having the article in my hand here at
home...



>
>   an FPGA built using a 0.15 µm 8-Layer Metal process with 0.12 µm
>                         ^^^^^^^ ^^^^^^^^^^^^^
>   high-speed transistors.
>
>It's somewhat design dependent, but in general I would feel fairly comfortable
>saying that the FPGA should fare well. We prototyped an ASIC in Virtex parts
>which are clocked at 80 MHz - it's not just a DMA engine but contains pieces
>like 66 input multioperand adders. Something like a DMA engine design can easily
>be clocked at over 100 MHz.
>
>What does all this mean? We'll see. There may be design requirements which don't
>map well to the Virtex architecture. For instance building a CAM for repetition
>detection might be a bit tricky. Marc Boule was able to get his move generator
>working at 33 MHz - so there's one datapoint. The move generator should not be
>the bottleneck.
>
>Regards,
>Keith


The big headache is the same one present in DB.  You can build a "search engine"
but you can't get much back from it other than "best move" and "score".  I
really want the PV for testing/debugging.  :)

And then there is the hashing issue.  Hsu included hash table support in the
DB 2 chips, but didn't have time to design/build the multi-port memory to get
the on-chip hashing functional.  However, 80mhz sounds promising considering
DB used 10 cycles per _node_ for the search.  That translates into 8M nodes per
second.  Put a group of those together and this thing could fly...



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