Author: David Rasmussen
Date: 13:27:20 01/16/03
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On January 16, 2003 at 16:15:56, Dieter Buerssner wrote: >On January 16, 2003 at 15:37:07, David Rasmussen wrote: > > EGTB probes: 25055 > ^^^^^ >>1. Bxg5 >> >>That is quite a speed drop. What I don't understand is that during this search, >>the disk is working like crazy. I only probe in the first 2 plys. > >?? >This doesn't seem to matter at all. > What do you mean? >> There is 11 >>legal moves in the position, so that's roughly 100 positions. That can't take >>that much activity to probe. And then I only probe within the iteration depth, >>and only then if there have been a capture or a promotion, and only if the >>number of pieces on the board is small enough (<= 5 for 3-5 man tables). In this >>position, there is of course a capture now and then, and a promotion sometimes >>too. But why this constant disk access? > >Even for a fast disk, 25000 random accesses will take a long time. Many of those >will have been cached, otherwise it would even be much slower. > >I get a similar slowdown and a comparable number of TB-accesses here with my >engine. > I'm "glad" to hear it. So you're saying that what I'm seeing is normal. But then: How come all sorts of engines on ICC (Baron, Comet and others come to mind) don't lose anywhere near this much speed when probing. >Just testing a position will not be a good test for normal games. There all the >caches will have time to "warm up". When you try the same position a second time >(of course again not a good test), you will probably see a big difference. > But the problem happens all the time in normal games (if they reach late end game anyway). I search 600knps and then when the late endgame comes, it gets slower and slower and I'm searching 100knps or 50knps, while the opponent is often unaffected or maybe drops from 500knps to 400knps or something like that. /David
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