Author: Andreas Stabel
Date: 04:59:18 09/25/02
Go up one level in this thread
On September 25, 2002 at 07:48:12, Vincent Diepeveen wrote: >Hello, > >I'm looking to a quick alternative for the windows >function WaitForSingleObject(); > >It waits until it gets signaled or times out after xx milliseconds. > >I go use it for the i/o thread which is supposed to sit >idle till the end of a ply or till it checks for input or >the clock. I remember for unix something about select and >such but i completely lost that code. Also i want to know what >speed it runs at. Because the first 10 ply or so which get >out of hashtable with 40 legal moves, it is done instantly after >a ply starts, and obviously it means that i need to do this 400 >times instantly after a search starts. i don't want to wait >real long there for just the first few ply! > >The second thing i sit with is that all processes at start of the search >need to sit idle till they get a job. Previously what i did was >letting them spin. That's pretty impossible. Under Irix i'm using >spin_lock() here. It suspends processes when it can't lock in. >Select and such i never managed to figure out and most likely >signalling interprocessor is pretty hard and manual page of irix >says that select only goes till 128 processors anyway. Partitions >bigger than that it doesn't work simply. > >So where spin_lock is an idea for irix, i might guess WaitforSingleObject >is working for windows (better alternatives i have an open mind for too) >and it's a mystery to me what to use under linux. > >The problem is i can't use pthread_cond_wait, because >it's not only an i/o thread that has to get signalled, but >several other processes must be able to do it too... > >I asked SGI and they had no good alternative for me apart from >the existing spin_lock which i already use and usema. So >i guess i go do it with spin_lock() there. > >Basically the machine is ideal for multiprocessing, but amazingly >there is not much info about it, like most OSes they focussed >even more upon multithreading (which i find a wrong approach, BOTH >should get attention). usema is something i will try if spin_lock() >doesn't work out well. > >Best Regards, >Vincent I think the good old select covers all this on Unix. Regards Andreas
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