Search found 17071 matches

by bob
Fri Aug 24, 2007 7:06 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: re-inventing the SMP wheel
Replies: 81
Views: 37370

Re: re-inventing the SMP wheel

Believe me, this has not been developed in an ad hoc way over the past 30 years, it has been studied, simulated and measured to death, to get us to where we are today. This does not answer the most important question, though: is the optimum page size dependent on total memory size or not? If not, h...
by bob
Fri Aug 24, 2007 4:16 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: re-inventing the SMP wheel
Replies: 81
Views: 37370

Re: re-inventing the SMP wheel

Well, the eval I have in mind doesn't really use much memory at all. 32KB is huge. Adding a few Piece-Square Tables for each piece type (16 x 64 bytes = 1KB) would not kill me. But playing a match without them will just tell you next to nothing. About paging: When you allocate a small object, you a...
by bob
Fri Aug 24, 2007 12:46 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: re-inventing the SMP wheel
Replies: 81
Views: 37370

Re: re-inventing the SMP wheel

First let's try a match between your non-real program and my real-program, to see if there is any advantage to a program that is optimized to fit L1 rather than optimized to play the best possible game of chess. That's my point about "real programs". To play the game of chess well, you need a prett...
by bob
Thu Aug 23, 2007 8:15 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: re-inventing the SMP wheel
Replies: 81
Views: 37370

Re: re-inventing the SMP wheel

I doubt "real programs" are going to fit in L1. No doubt an intentionally small program can, but that won't predict anything about how the real programs are going to perform, which is where we started this discussion... My definition of a "real program" is at the very least, a program that has no c...
by bob
Thu Aug 23, 2007 6:23 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: re-inventing the SMP wheel
Replies: 81
Views: 37370

Re: re-inventing the SMP wheel

To get back on topic: It still bothers me that at split points there would be multiple threads each generatinfg moves for the same position. So I wonder if there would be some gain in having only one thread, the one that 'owns' the node and has opened the hash entry for it, to generate moves, and p...
by bob
Thu Aug 23, 2007 6:10 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: re-inventing the SMP wheel
Replies: 81
Views: 37370

Re: re-inventing the SMP wheel

The math looks tough to me. 16K lines mapping into a set that only holds 16 line, is a 1024 to 1 mapping. Not really. Because 1024 is a large number, randomly assigning the pages becomes the same as randomly deciding per page if it is used or not, with a certain probability. This leads to Poisson s...
by bob
Thu Aug 23, 2007 5:56 pm
Forum: Computer Chess Club: General Topics
Topic: EGTB's accesed from the internet?
Replies: 14
Views: 7326

Re: EGTB's accesed from the internet?

You can easily do that. But the cost is prohibitive, in that the program will play so incredibly weakly because of the internet latency. Currently you do a probe and get an answer back in a few milliseconds. On the internet, multiply that by 100 or 1000, and it would absolutely kill the search spee...
by bob
Thu Aug 23, 2007 1:31 am
Forum: Computer Chess Club: General Topics
Topic: interesting position
Replies: 11
Views: 4891

Re: interesting position

In this game http://www.chessgames.com/perl/chessgame?gid=1441216 there is mention of a sideline analyzed by GM Golubov. The end of the line is this position: [D] 5k1r/r3b2p/p3Qp2/qp1p4/8/2R5/1PP2PPP/4R1K1 w - - here it is said h4 is winning but computers take "several minutes" to see it. I tried A...
by bob
Thu Aug 23, 2007 1:16 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: If You Were Starting From Scratch
Replies: 8
Views: 4825

Re: If You Were Starting From Scratch

l have a good position structure well suited to SMP, I think. I am still not sure how best to handle move history for rep detection across multiple processors. but it seems to be going well. Mark, WOW - big step! Here's what I'd do (actually have done - I seem to have rewrite-titis) when re-writing...
by bob
Wed Aug 22, 2007 8:26 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: re-inventing the SMP wheel
Replies: 81
Views: 37370

Re: re-inventing the SMP wheel

Another way to look at it is this: Suppose the processing of each node causes N cache misses (hash probe included), that are randomly distributed over L2. Then in a 4MB cache, with 64K lines, you need a tree of 64K/N nodes before (on the average) a probed entry is flushed from the cache before the ...