Author: Robert Hyatt
Date: 06:44:05 09/27/01
Go up one level in this thread
On September 27, 2001 at 01:01:40, Will Singleton wrote: >On September 26, 2001 at 22:28:06, Robert Hyatt wrote: > >>The critical question then is are you copying any large structs around? Are >>you doing a make/unmake or a copy/make approach (copy/make drains the PC >>memory bandwidth to zero). > >I do copy/make, but my struct isn't that large (a few words). Could you >elaborate on the problem with copy/make? > >Will In a much earlier version of Crafty, I did copy/make also, the idea being that there is then no unmake at all. Using bitboards, I have 12 for the different pieces, plus three rotated, plus two (white/black occupied) plus one for bishops/queens and one for rooks/queens. A total of 19 (at least). Times 8 bytes. The PC has almost _no_ memory bandwidth. It is somewhere around 100mbytes/second depending on your machine, maybe as much as 2x that. The "copy" operation fries that bandwidth + cache badly. I became over 2x faster by going to make/unmake...
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.