Re: [Bug-gnubg] Re: Getting gnubg to use all available cores

[Louis Zulli]

Hi,

I put

#define MAX_NUMTHREADS 64

in multithread.h and rebuilt.

In Settings-->Options-->Other, I put Eval Threads to 64.

I then let gnubg analyze a game using 4-ply analysis.

According to my unix top command, gnubg had 69 threads and was using  
188%CPU. So apparently all the threads were running (into each other!)  
in one physical core.

In any case, increasing the max number of threads above 16 seems  
trivial to do, unless I'm missing something.

Louis


On Aug 6, 2009, at 11:34 AM, Ingo Macherius wrote:

> Do you use the calibrate command or a batch analysis of matchfiles?  
> The
> former was shown to be of no value for benchmarks, see here:
> http://lists.gnu.org/archive/html/bug-gnubg/2009-08/msg00006.html
>
> With calibrate I had the very same effect of high idle times during
> benchmarks, unless I used at least 8 threads per physical core.
>
> I am doing benchmark on a 4 core machine which iterates over #thread  
> (1..6)
> and cache size (2^1 .. 2^27). Should be posted in say 3 hours, it  
> literally
> is still running :)
>
> Ingo
>
> > -----Original Message-----
> > From: address@hidden
> > [mailto:address@hidden On
> > Behalf Of Louis Zulli
> > Sent: Thursday, August 06, 2009 3:21 PM
> > To: Michael Petch
> > Cc: address@hidden
> > Subject: [Bug-gnubg] Re: Getting gnubg to use all available cores
> >
> >
> >
> > On Aug 5, 2009, at 4:02 PM, Michael Petch 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?
> >
> >
> > Hi Mike,
> >
> > Sorry for the delay. I just had two copies of gnubg analyze the same
> > game, using 3 ply analysis. Each instance of gnubg used 200%
> > CPU. Each
> > copy was set to use 4 evaluation threads.
> >
> > So what's the verdict here? Is Leopard simply not directing threads
> > correctly?
> >
> > Louis
> >
> >
> >
> >
> >
> > _______________________________________________
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