Author: Vincent Diepeveen
Date: 11:39:39 08/13/01
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On August 12, 2001 at 09:06:02, Kim Roper Jensen wrote: >I have made a little chess program with some very ordinary stuff, and would like >to implement multiprocessing( i just recently bought a dual 1GHz with 2Gb of >memory, its real cheap here in denmark it only costed approx $1000) > >But i wondered how do you guys implement it, i was thinking about having a pool >of threads that the search could grab if there is some available, then it would >be easy to test to see which amount of threads would be the most efficient and >it could be adjusted easily. > >Or do you just have a finite amount of threads that you start at once ???? > >I just had some thoughts that maybe the amount of threads that would yield the >best perfomance could change in the course of the game and it would be more >efficient to adjust the poolsize of threads in the different stages of the game. You shouldn't worry too much about whether a thread has its own hashtable (bad plan btw will cost you many plies compared to a shared hashtable), you shouldn't worry about how many threads either, you should basically worry how to divide the search tree to the threads and how to implement the locking without race conditions or other hard to trace bugs! >and how about having each thread using its own hashtable ?? This maybe sound >silly but the we shouldnt check all kinds of things( is there another thread >locking the table at the location etc.) maybe the there would be some small >speed benefit( I mean, I read that implementing hashtables only gives approx. 70 >ratingpoints, so maybe it isnt so critical to use one big table) lineair speedup never translates lineair into rating, don't worry about details that have nothing to do with the parallellism itself. >just some thoughts ............ > >(if it sounds really crazy, then it must be because its late and im tired :) )
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