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Subject: Re: [OMPI users] Tuned collectives: How to choose them dynamically? (-mca coll_tuned_dynamic_rules_filename dyn_rules)"
From: Lenny Verkhovsky (lenny.verkhovsky_at_[hidden])
Date: 2009-08-04 03:12:16


Hi,
I am looking too for a file example of rules for dynamic collectives,
Have anybody tried it ? Where can I find a proper syntax for it ?

thanks.
Lenny.

On Thu, Jul 23, 2009 at 3:08 PM, Igor Kozin <i.n.kozin_at_[hidden]>wrote:

> Hi Gus,
> I played with collectives a few months ago. Details are here
> http://www.cse.scitech.ac.uk/disco/publications/WorkingNotes.ConnectX.pdf
> That was in the context of 1.2.6
>
> You can get available tuning options by doing
> ompi_info -all -mca coll_tuned_use_dynamic_rules 1 | grep alltoall
> and similarly for other collectives.
>
> Best,
> Igor
>
> 2009/7/23 Gus Correa <gus_at_[hidden]>:
> > Dear OpenMPI experts
> >
> > I would like to experiment with the OpenMPI tuned collectives,
> > hoping to improve the performance of some programs we run
> > in production mode.
> >
> > However, I could not find any documentation on how to select the
> > different collective algorithms and other parameters.
> > In particular, I would love to read an explanation clarifying
> > the syntax and meaning of the lines on "dyn_rules"
> > file that is passed to
> > "-mca coll_tuned_dynamic_rules_filename ./dyn_rules"
> >
> > Recently there was an interesting discussion on the list
> > about this topic. It showed that choosing the right collective
> > algorithm can make a big difference in overall performance:
> >
> > http://www.open-mpi.org/community/lists/users/2009/05/9355.php
> > http://www.open-mpi.org/community/lists/users/2009/05/9399.php
> > http://www.open-mpi.org/community/lists/users/2009/05/9401.php
> > http://www.open-mpi.org/community/lists/users/2009/05/9419.php
> >
> > However, the thread was concentrated on "MPI_Alltoall".
> > Nothing was said about other collective functions.
> > Not much was said about the
> > "tuned collective dynamic rules" file syntax,
> > the meaning of its parameters, etc.
> >
> > Is there any source of information about that which I missed?
> > Thank you for any pointers or clarifications.
> >
> > Gus Correa
> > ---------------------------------------------------------------------
> > Gustavo Correa
> > Lamont-Doherty Earth Observatory - Columbia University
> > Palisades, NY, 10964-8000 - USA
> > ---------------------------------------------------------------------
> > _______________________________________________
> > users mailing list
> > users_at_[hidden]
> > http://www.open-mpi.org/mailman/listinfo.cgi/users
> >
>
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