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Subject: Re: movegen speeds(was Re: Status of Brutus?)

Author: Keith Evans

Date: 15:18:31 07/29/03

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On July 29, 2003 at 17:35:01, Vincent Diepeveen wrote:

>On July 29, 2003 at 17:14:52, Keith Evans wrote:
>
>>On July 29, 2003 at 17:04:44, Vincent Diepeveen wrote:
>>
>>>On July 29, 2003 at 16:13:19, Keith Evans wrote:
>>>
>>>>On July 29, 2003 at 16:00:20, Tord Romstad wrote:
>>>>
>>>>>On July 29, 2003 at 12:49:49, Keith Evans wrote:
>>>>>
>>>>>>You're perft performance seems pretty decent to me.
>>>>>
>>>>>Indeed.  I just did a similar test with my own program on a Pentium 4 2.4 GHz.
>>>>>In the position after 1. e4 e5 2. d4 d5, my program generates 30 million moves
>>>>>per second.  I guess I could speed it up somewhat, but I don't think I would
>>>>>come anywhere close to the speeds reported by Vincent and Angrim.
>>>>>
>>>>>My move genererator assigns all moves a move ordering score, and also
>>>>>determines which moves are checks.  It generates legal moves only.
>>>>>
>>>>>But anyway, I don't understand why people spend so much time and energy on
>>>>>micro-optimising their move generators.  Despite my slow movegen speed, my
>>>>>program spends only 1 or 2 percent of its time in the move generator.  I
>>>>>guess most other programmers have similar numbers.
>>>>>
>>>>>Tord
>>>>
>>>>I'm personally interested in the performance of the move generator in a hardware
>>>>chess chip where it is a large percentage of the total cycles. If it were only
>>>>1-2% of the time then I wouldn't be interested. Of course a hardware move
>>>>generator can generate millions of NPS when only running at say 30 MHz, so it's
>>>>a totally different animal than a software generator running on a 3 GHz
>>>>processor.
>>>
>>>hardware doesn't work like that. you cannot store the moves.
>>>
>>
>>Huh? (Duh?) Where did I say that it pregenerates and stores the moves? Of course
>>it generates them incrementally.
>
>but i hope you realize how hard it is to order moves when all you have is 1
>bound that gives how far the incremental generation is.
>
>but if you compare speeds.
>
>Say that each move costs 1 clock. that's 30 million moves a second at 30Mhz
>right?
>
>Brutus ran at 2002 WCC at something like 33Mhz. So that's 33 MLN a second.
>
>DIEP i generate way more than 33MLN a second at the 1.6Ghz K7 i had back then.
>
>At 2.127Ghz it is about 72MLN. this with slow RAM storage. It's probably
>relatively faster at a P4 generating moves because of the fast L1 cache there
>and everything runs within trace cache when doing a loop for a few millions of
>times.
>

Can you do perft at 72 million NPS? (Actually traverse a tree?) If not then
you're quoting something different. You could use Chrilly's 7 cycle/node number
which should include everything to generate, make, and unmake moves. So at 33
MHz that would be 4.7 MNPS.



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