On my core i7-3770, 4 threads is 12.5K playouts/sec (19x19, average of first four moves by white), and 8 threads is 19.8K, a 58% increase. This is much higher than I expected. It seems Intel has improved hyperthreading since the last time I tried it. Or it might be an artifact of the way I do search, since I think I might be the only engine that doesn't use a single shared tree, and the old Many Faces of Go engine is single threaded.
David > -----Original Message----- > From: computer-go-boun...@dvandva.org [mailto:computer-go- > boun...@dvandva.org] On Behalf Of Petr Baudis > Sent: Thursday, August 09, 2012 6:23 AM > To: computer-go@dvandva.org > Subject: Re: [Computer-go] Kas Cup - results and prizes > > On Thu, Aug 09, 2012 at 08:09:55PM +0900, Hideki Kato wrote: > > Erik van der Werf: <CAKkgGrM83_HsQ5Z2HJupkj=gDeh3+4GM- > jmlvevtjroufqn...@mail.gmail.com>: > > >10-15%, really, that low? For my program (on an i7-3930K, going from > > >6 to > > >12 threads) it is more in the order of 40% extra simulations per > second. > > > > In general that number highly depends on the code, architecture of the > > processor (Intel's are usually better than AMD's), memory speed, cache > > size, use of ALUs, etc. For Zen, the number is also about 40% on both > > an i7 3930K (6 to 12 threads) and an i7 920 (4 to 8 threads). > > For Zen, I'm not surprised, since I assume that in simulations, you are > matching some larger patterns which involves a lot of time-consuming > hash table lookups which is ideal for hyperthreading. Not sure about > stv. I think it matters a lot on whether you are matching patterns by > explicit test code snippets or by a hash table. > > I measured the hyperthreading effect about 2 years ago with a lot older > Pachi version. I think today, the hyperthreading effect would also be > higher, but I cannot test it right now. > > > Pasky, modern processors are much more complicated :). There are more > > than two sets of general registers, which are used not only for > > hyperthreading but also register renaming, for example. > > Sure, I just tried to sketch a rough explanation. I did not know that > hyperthreading could reduce opportunity for register renaming, though. > > Petr "Pasky" Baudis > _______________________________________________ > 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
