Open MPI logo

Open MPI User's Mailing List Archives

  |   Home   |   Support   |   FAQ   |  

This web mail archive is frozen.

This page is part of a frozen web archive of this mailing list.

You can still navigate around this archive, but know that no new mails have been added to it since July of 2016.

Click here to be taken to the new web archives of this list; it includes all the mails that are in this frozen archive plus all new mails that have been sent to the list since it was migrated to the new archives.

Subject: Re: [OMPI users] Any scientific application heavily using MPI_Barrier?
From: Ganesh (ganesh_at_[hidden])
Date: 2009-03-05 10:58:12

> Thank you, Jeff and Ganesh.
> My current research is trying to rewrite some collective MPI
> operations to work with our system. Barrier is my first step, maybe I
> will have bcast and reduce in the future. I understand that some
> applications used too many unnecessary barriers. But here what I want
> is just an application to measure the performance improvement versus
> normal MPI_Barrier. And the improvement can only be measured if the
> barriers are executed many times. I have done some synthetic tests,
> all I need now are real applications.
Looks like a useful project.

BTW in our paper, we cite a paper by Rolf Rabenseifner. That paper is
definitely worth reading. It provides interesting performance studies
(the paper cited is old, so the studies are probably worth repeating).

Then again, in our paper we cite a paper by Siegel et al. That is also
definitely worth reading. In that paper, they mention a real-world
experience story of a barrier that was thought to be useless and was
removed... only to find, a year later, that it caused a communication
race (a wildcard receive now could obtain an extra match that was not
possible with the barrier present).

Good luck in your studies, Shan.

> Shan
> _______________________________________________
> users mailing list
> users_at_[hidden]