Author: Robert Hyatt
Date: 06:19:57 09/24/01
Go up one level in this thread
On September 23, 2001 at 18:32:50, Vincent Diepeveen wrote: > >The average test done here at CCC is 10 to 20 seconds a move. > >Even the new try to make a WACII the dudes test at most at 1 minute >a move. > >So you're kind of wrong here. You are mixing apples and oranges. The tests here have _nothing_ to do with trying to measure SMP efficiency. > >Most tests in ICCA and advances in ICCA are based upon anything under or >equal to 8 ply. Again apples and oranges. _most_ ICCA and ACCX articles are pretty old when you look for ones dealing with parallel search. The older the article, the shallower the depth. If you find by DTS article you will not find _it_ based on shallow searches. In fact many of the single-cpu searches took _hours_ to run because the 16 cpu tests took minutes for each position. > >I can only remember a single article 'crafty goes deep' where some >deeper searches were done. > Find the DTS article. It had deep searches. And please don't start the "but Cray Blitz didn't use null-move R=3" and such nonsense. I'll be happy to show you that the parallel speedup in Crafty is 100% independent of null-move usage. I can turn it off totally, use R=1 (or with a simple source change make it non-recursive R=1 just like CB) and produce some parallel speedup numbers. The speedup is independent of null-move although the overall search depth shrinks as expected. Old SMP articles are not junk. If I were going to criticize _any_ SMP issues that have been reported, it would be anyone that claims that a speedup of > 2.0 is possible, while talking about how his move ordering is better than anybody else's. It simply isn't possible for _both_ of those conditions to be true. One or the other, maybe. But a speedup > 2 means big problems in the non- parallel search. >> >>> Now, if that improvement isn't made, then you're testing a good >>>>parallel implementation against a poor sequential implementation, so your >>>>speedup value is meaningless. >>>> >>>>Dave >>> >>>The speedup value is not meaningless because it is possible that the cutomer >>>need to choose between poor sequential implementation and good parrallel >>>implentation so from the customer's point of view it may be important to know it >>>before deciding if to buy a machine with more processors. >> >>Parallel speedup is a scientific concept, used when reporting analyses of >>parallel search performance. What form of product is shipped to a chess >>software program customer is quite irrelevant. >> >>Dave
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