Michael Williams: <CAB0EdYWgs=gjsnt9rmkj8-utlg72nyxnafvd-8iq_pjjf_j...@mail.gmail.com>: >I wonder if spin-lock hurts hyperthreading.
Why do you think so? If a spin-lock accesses memory and waits, simply another thread runs. That's all. Hideki >On Sat, Aug 11, 2012 at 7:22 PM, Hideki Kato <hideki_ka...@ybb.ne.jp> wrote: >> Petr Baudis: <20120811145900.gv19...@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 >> acceralaton. >> >> Hideki >> -- >> Hideki Kato <mailto:hideki_ka...@ybb.ne.jp> >> _______________________________________________ >> Computer-go mailing list >> Computer-go@dvandva.org >> http://dvandva.org/cgi-bin/mailman/listinfo/computer-go >_______________________________________________ >Computer-go mailing list >Computer-go@dvandva.org >http://dvandva.org/cgi-bin/mailman/listinfo/computer-go -- Hideki Kato <mailto:hideki_ka...@ybb.ne.jp> _______________________________________________ Computer-go mailing list Computer-go@dvandva.org http://dvandva.org/cgi-bin/mailman/listinfo/computer-go
