Author: Vincent Diepeveen
Date: 19:37:37 09/24/01
Go up one level in this thread
On September 24, 2001 at 09:19:57, Robert Hyatt wrote: >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. it has, at 1 minute a move my speedup is not even close to 2.0 it's more like 1.6 to 1.8 > >> >>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. Yes and you claimed a 2.0 speedup at 2 processors. Pretty impressive considering the time when you wrote the algorithm, and in assembly! > > >> >>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" You got 2.0, i get 2.0. Now you say i'm big shit somehow. Why? Note that the statement that i could do things on 1 processor quicker then i can proof incorrect. If you can do the same thing which you do on 2 processor but now on 1 processor, then that would implicitly mean that 2 processors are deterministic. Because behaviour at 1 processor is deterministic for me. At 2 it is not. So i cannot do what i do on 2 processors in one process. How's that? >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, Crafty is recursive Bob. You keep splitting at the wrong points too, i have no idea what kind of difference that shows, more interesting is if you can get cray blitz alive again and run it for my part at an old cray but then with R=3 , no singular extensions and futility turned off. the interesting thing which you also didn't write down in your articles, probably because of space is the speedup you get at the different depths. speedup at 8 ply, 9 ply, 10 ply, 11 ply , 12 ply etc. To see a graph of it. >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. The difference is i never claimed it to be non improvable. You did a few years ago though. You were not the only one saying it was hardly improvable. >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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