Author: Robert Hyatt
Date: 07:24:41 08/31/01
Go up one level in this thread
On August 31, 2001 at 09:06:42, Vincent Diepeveen wrote: >On August 30, 2001 at 23:21:58, Robert Hyatt wrote: > >>On August 30, 2001 at 20:48:30, Vincent Diepeveen wrote: >> >>>On August 30, 2001 at 14:43:00, Robert Hyatt wrote: >>> >>>>On August 30, 2001 at 14:25:39, Scott Gasch wrote: >>>> >>>>>On August 30, 2001 at 14:07:50, Dann Corbit wrote: >>>>> >>>>>> >>>>>>Dumb question: >>>>>>Why not let them all have their own move generator and just share the hash >>>>>>table? >>>>> >>>>>I guess that's one approach -- run them as seperate processes in seperate >>>>>virtual address spaces and simply share the hash table. I was planning on using >>>>>simple threads in the same address space though. Not sure why, seems more >>>>>straightforward to me... >>>> >>>> >>>>One reason is that there are other things to share. Killer moves. History >>>>move counts. move lists (you need to share a move list at a ply where more >>>>than one processor is searching) and so forth... >>> >>>No you don't want to share killer moves. History moves do not give >>>a speedup if you write a bunch of extra rules to order moves. >> >>Sure you do, if you do it right. I share them. And history moves are better >>than random, and work fine for everyone that has tried them. > >You don't want to share killermoves, as each processor searches its >own tree, though there might be transpositions, the most important thing >are the killermoves which gets updated each time. The second killer in >my killermove list is hardly of any statistical significance in DIEP. Try using the ply-2 killers at ply, as we did in Cray Blitz. _then_ you will want to share the earlier killers. I'm not talking about a set of killer moves that is common to all threads. I am talking about separate lists of killers for each thread, but they have common moves prior to split plies. > >So a killer which kills this line is interesting. > >Suppose now that in parallel 2 processes are writing into a killer list, >both having a complete different position at their board, that's quite >silly isn't it? If that was what I was talking about, yes. But notice we are discussing what to put in a structure that is unique for each thread, but which can have common data for plies prior to a split point. > >>There's dozens of things that need to be shared. I can dump my shared structure >>here if needed to show what I share. >> >>It is pretty large however.
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