[Computer-go] Kas Cup - results and prizes
hideki_katoh at ybb.ne.jp
Sat Aug 11 19:22:09 PDT 2012
Petr Baudis: <20120811145900.GV19484 at machine.or.cz>:
>On Sat, Aug 11, 2012 at 12:52:12AM -0700, David Fotland wrote:
>> Yes, root parallelization with some sharing.
>> http://www.personeel.unimaas.nl/G-Chaslot/papers/parallelMCTS.pdf said it
>> was good and I tried it and it works well.
>The paper is not so relevant now, since the standard method of most
>programs is lockless tree parallelization, which is not covered.
>The locking overhead is quite significant, I'd expect, as locking
>instructions can AFAIK take hundreds of cycles.
With spin-lock or hardware test-and-set instructions, locking overhead
is very small.
>That said, root parallelization overperforming sequential simulations
>is something I never managed to reproduce and that seems rather
>surprising to me. It might have something to do with the way priors
>are done in the tree or some other engine-specific factors.
I believe IBM Power processor's architecture may caused the super-linear
Hideki Kato <mailto:hideki_katoh at ybb.ne.jp>
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