Author: Robert Hyatt
Date: 13:13:45 09/25/02
Go up one level in this thread
On September 25, 2002 at 14:51:30, Vincent Diepeveen wrote: >On September 25, 2002 at 11:49:25, Russell Reagan wrote: > >Windows doesn't work at all above 64 processors AFAIK. >Linux doesn't work above 8 processors AFAIK. > >But i'm looking for a cheap solution under linux now too >and i see nowhere at manual pages of linux an example of how >to do it. basically this is THE big problem under linux. > >MSDN under windows however shows about 100 examples how to >do WaitForSingleObject.\ Any idea how this is implemented? I do. It is a system call and it is just as ugly as select() or anything else... > >Of course other solutions to do the job are fine too here. >I know under unix that the pthread libraries have something >called pthread_cond_wait. > >this is a great function, but i can't use it, as my program is >SMP, so SYMMETRIC MULTIPROCESSING. Don't follow that. pthreads is based on SMP. But I think you are just misusing a common term. SMP does not mean using fork() as you are doing. But even with fork() processes, you can use the pthread stuff. Just stuff the things into shared memory... > >It means that all processors are equal. It means that any >processor might terminate a certain iteration as last one. > really lost me there. I use pthreads and that is _exactly_ how my search works... >This one has to signal the i/o thread, which is a thread from >some other process most likely (big chance with 512 processors). > >The current idea for linux is to sleep for 5 milliseconds and >checkout whether an iteration has finished. So that's a possible >waste of about 4 milliseconds times n moves (can be 50 or so), >so that's losing each ply 0.2 seconds. if you get in endgame 11 >ply out of hashtable that's 11 x 0.2 = 2.2 seconds. > >That is a big waste of seconds in a 1 0 game for example online >at a dual k7. > Don't do it like that... > > > >>On September 25, 2002 at 08:10:06, Vincent Diepeveen wrote: >> >>>i cannot use select() at all as i limit myself to < 128 processor >>>partitions then. >> >>Does WaitForSingleObject or WaitForMultipleObjects allow you to use more than >>128 processors? >> >>>also i have no idea how to get it to work and whether it can do >>>it 400 times a second instantly. >> >>See the problems Microsoft causes? They always have to be different (in a bad >>evil kind of way).
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