Open MPI logo

Open MPI User's Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Open MPI User's mailing list

Subject: Re: [OMPI users] strange IMB runs
From: Michael Di Domenico (mdidomenico4_at_[hidden])
Date: 2009-07-30 11:37:04


On Thu, Jul 30, 2009 at 10:08 AM, George Bosilca<bosilca_at_[hidden]> wrote:
> The leave pinned will not help in this context. It can only help for devices
> capable of real RMA operations and that require pinned memory, which
> unfortunately is not the case for TCP. What is [really] strange about your
> results is that you get a 4 times better bandwidth over TCP than over shared
> memory. Over TCP there are 2 extra memory copies (compared with sm) plus a
> bunch of syscalls, so there is absolutely no reason to get better
> performance.
>
> The Open MPI version is something you compiled or it came installed with the
> OS? If you compiled it can you please provide us the configure line?

OpenMPI was compiled from source v1.3 with only a --prefix line, no
other options.