Author: Albert Silver
Date: 18:42:59 06/29/00
Go up one level in this thread
On June 29, 2000 at 13:25:19, Tom Kerrigan wrote:
>On June 29, 2000 at 03:38:38, Albert Silver wrote:
>
>>On June 29, 2000 at 02:21:10, Gregor Overney wrote:
>>
>>>>Not even close yet. That hardware would be approximately 1% of the power of
>>>>the DB hardware. And that is being _very_ generous...
>>>
>>>1% is a pretty good estimate for a four processor machine using four P5-4
>>>running at 1.5 GHz using a four channel RDRAM bus that delivers 3.2 GB of data.
>>>Estimate 500 kNodes per CPU times 4 = 2M Nodes = 1% of DB's avarage performance.
>>
>>If one CPU achieves 500k nodes, I doubt very much that 4 CPUs will achieve 2M
>>nodes, unless 100% efficiency has been achieved. Crafty is apparently the most
>>efficient at this level though only Bob would be able to say how well it should
>>do.
>
>No, believe it or not, Bob Hyatt is not the only competent chess programmer in
>the world.
:-))) Clearly you are trying to trick me Oh Evil One! But I am not fooled by
your daring attempts to lure me into your dastardly plots!
Seriously though, all I said was that as far as I knew ("apparently") Crafty was
the most efficient multi-processor chess program among the micros. This wasn't
based on any worshipping of the 'Great One', but on what I had been led to
understand from my reading here. If there is a microcomputer chess program that
makes better use of multi-processor systems, please just say which.
>
>In any case, who says that DB was searching at 100% "efficiency"?
Actually, I wasn't talking about DB's efficiency at all, but merely the
well-known figure of 200M NPS. Greg had said that a four processor machine would
reach 1% of DB average performance, and said this by merely multiplying the NPS
achieved by each processor. I questioned this conclusion and waited to be
corrected, that's all.
Albert Silver
> (I assume you
>mean overhead from the parallel search.) DB was composed of HUNDREDS of
>processors, and each processor was pretty localized from the others. Compared to
>a PC program running on only 4 processors with a shared hash table, etc., the
>overhead of DB must have been tremendous.
>
>-Tom
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