[Pw_forum] newbie update

[Lex Kemper]

Hey Axel,

In my case, exporting OMP_NUM_THREADS from my .bashrc was sufficient. 
I guess that's not the case everywhere.

Thanks!

Lex

Axel Kohlmeyer wrote:
> On Wed, 4 Mar 2009, Lex Kemper wrote:
> 
> LK> Out of curiosity, what behaviour do you see from MKL that it doesn't 
> LK> obey OMP_NUM_THREADS? I ask, because that's what I'm using, and would 
> LK> like to make sure it's behaving right.
> 
> lex,
> 
> it doubt it is mkl that is to blame, but rather the mpirun
> script/wrapper not exporting environment variables to all tasks,
> even on remote nodes. if you have a good sysadmin running your
> machine her or she will have already set OMP_NUM_THREADS=1
> in the default environment.
> 
> with openmpi, for example, the environment is not exported
> unless explicitly set it via a flag.
> 
> linking the sequential version of mkl (see mkl docs for)
> details, is the solution for paranoid people (like me).
> 
> cheers,
>    axel.
> 
> LK> 
> LK> Thanks,
> LK> 
> LK> Lex Kemper
> LK> University of Florida
> LK> 
> LK> Axel Kohlmeyer wrote:
> LK> > On Wed, 4 Mar 2009, JR Schmidt wrote:
> LK> > 
> LK> > JRS> I had problems with MKL not obeyig OMP_NUM_THREADS.  I found it was 
> LK> > JRS> easier to simply link with the MKL serial (non-threaded) library, since 
> LK> > JRS> that is what you want anyway.
> LK> > 
> LK> > yes. but in carlo's case it _does_ work correctly.
> LK> > 
> LK> > axel.
> LK> > 
> LK> > JRS> > I tried to run the example01 with the following settings:
> LK> > JRS> >
> LK> > JRS> > OMP_NUM_THREADS=1
> LK> > JRS> > mpiexec -n 8
> LK> > JRS> >
> LK> > JRS> > The example is executed, but with a very long time. All 8
> LK> > JRS> > CPUs are running
> LK> > JRS> >   
> LK> > JRS> 
> LK> > 
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> LK> 
>