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Subject: Re: Chess and Clusters

Author: Dann Corbit

Date: 15:39:47 09/15/05

Go up one level in this thread


On September 15, 2005 at 18:16:32, Gian-Carlo Pascutto wrote:

>On September 15, 2005 at 17:01:37, Dann Corbit wrote:
>
>>On September 15, 2005 at 16:23:13, Gian-Carlo Pascutto wrote:
>>
>>>On September 15, 2005 at 15:17:13, Michael Yee wrote:
>>>
>>>>On September 15, 2005 at 15:13:22, Joshua Shriver wrote:
>>>>
>>>>>Has anyone tried writing an engine that uses PVM, MPI, or Mosix?
>>>>>
>>>>>If you had gigabit, or even fibre wire would the latency still be a problem?
>>>>>
>>>>>Josh
>>>>
>>>>The chessbrain project actually used a distributed beowulf over the internet:
>>>>
>>>>http://www.chessbrain.net/
>>>
>>>And they never published any serious result or test.
>>
>>This is interesting:
>>http://www.chessbrain.net/docs/chessbrain-discc.pdf
>>
>>Additional overviews:
>>http://www.chessbrain.net/docs/thechessbrainproject.pdf
>>http://www.chessbrain.net/docs/cblinuxjournal0903.pdf
>
>There is nothing interesting in there. In fact these reports don't do much more
>than say "we connected a lot of computers and had them play chess".
>
>No single performance metric.

5.3 Game Statistics
The total number of useful nodes processed was 84,771,654,525; that is the
number of nodes calculated for work units that were accepted by the central
server. Many more nodes were processed in work units that were never delivered
due to server connection issues, as well as those nodes that were aborted before
a result was returned. ChessBrain used a total of 2 hours, 15 minutes of
thinking time. Using just the useful returned data, this gives an average of
10.5 million nodes per second. By contrast, Beowulf analyses approximately
100,000 nodes per second in an average position on a single P4/2.8GHz machine.
This means, in terms of raw node processing, that ChessBrain performed at the
level of a single 280 GHz CPU.
These figures also tell us that ChessBrain’s efficiency in terms of converting
connected machines to raw processing power was approximately 100 / 2,070 = 5%.
Improving the central server architecture so that the connection problems are
resolved would improve this figure dramatically. We are working on a server
redesign to overcome this challenge before we enter any more high-profile
matches.

>Why?
>
>Was the speedup on 1000 machines <=1 ?

They got 5% efficiency.

>--
>GCP



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