Author: Sune Fischer
Date: 13:45:20 09/24/03
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On September 24, 2003 at 16:31:37, Robert Hyatt wrote: >"Think outside the box". > >the power of 2 is _not_ a memory address. It is a hash table index. If >an entry is (say) 48 bytes (in Crafty this is true as a single hash probe >accesses a "bucket" of three entries, one depth-preferred entry and two >always-store entries.) This means that my hash sizes are 3/4 of a true >power of two, which is why I use sizes like hash=48M, hash=96M, up to >hash=768M on my 1gb dual xeon box. > >That lets me use 3/4 of memory for hash (transpositions/refutations) and 1/4 >for the rest of the stuff like pawn hash, egtb cache, and whatever else I have >in the program. Suppose you had only 512 MB, then you would have to choose between 384 MB or 192 MB. The 384 might cause swapping and it has to be allocated in one big continues block might not even be possible, so you'd have to all the way down to 192 MB. Compare that to a program which is able to slide right in below the 384 MB, say 350 MB where no swapping occurs. -S.
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