Hi, 

Crafty uses POSIX threads, at least according to this: 



* 22.2 We are now back to using POSIX threads, since all current Linux * 
* distributions now use the posix-conforming NTPL implementation * 
* which should eliminate the various compatibility issues that * 
* caused problems in the past. 


Louis 

----- Original Message ----- 
From: "Michael Petch" <[email protected]> 
To: "Michael Petch" <[email protected]>, "Louis Zulli" 
<[email protected]> 
Cc: [email protected] 
Sent: Wednesday, August 5, 2009 4:22:09 PM GMT -05:00 US/Canada Eastern 
Subject: Re: [Bug-gnubg] Re: Getting gnubg to use all available cores 

The other possibility is that the gthread implementation on OS/X is 
buggy/limited. Gnubg is pretty much at the mercy of libgthreads to do all 
the thread work. If its poorly implemented for the Leopard/Nehalem 
environemnt it may have the side effect of using one physical core (and 2 
threads via hyperthreading). 

The chess program you use. Do you know if the code uses gthreads or does it 
possibly use OS/X native threading (Cocoas NSThread or Posix threads). 

On 05/08/09 2:02 PM, "Michael Petch" <[email protected]> wrote: 

> 
> I'm unsure how the architecture is deployed and how OS/X handles the 
> physical cores, but it almost sounds like one Physical core is being used 
> (Using Hyperthreads to run 2 threads simultaneously). I wonder if the memory 
> is shared across all the cores? A friend of mine was suggesting that people 
> may have to wait for Snow Lapard to come out before OS/X properly utilizes 
> the Nehalem architecture (whetehr that si true or not, I don't know). 
> 
> Anyway, as an experiment. If you run 2 copies of Gnubg at the same time 
> (using multiple threads) do you get 400% CPU usage? 
> 
> 
> 
> 
> _______________________________________________ 
> Bug-gnubg mailing list 
> [email protected] 
> http://lists.gnu.org/mailman/listinfo/bug-gnubg 
> 


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