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Subject: Re: [OMPI devel] Trunk Commit Heads-up: New Common Shared Memory Component
From: Samuel K. Gutierrez (samuel_at_[hidden])
Date: 2010-08-11 12:16:23


Hi Rich,

It's a modification to the existing common sm component. The
modifications do include the addition of a new POSIX shared memory
facility, however.

Sam

On Aug 11, 2010, at 10:05 AM, Graham, Richard L. wrote:

> Is this a modification of the existing component, or a new component ?
>
> Rich
>
>
> On 8/10/10 10:52 AM, "Samuel K. Gutierrez" <samuel_at_[hidden]> wrote:
>
> Hi,
>
> I wanted to give everyone a heads-up about a new POSIX shared memory
> component
> that has been in the works for a while now and is ready to be pushed
> into the
> trunk.
>
> http://bitbucket.org/samuelkgutierrez/ompi_posix_sm_new
>
> Some highlights:
> o New posix component now the new default.
> o May address some of the shared memory performance issues
> users
> encounter
> when OMPI's session directories are inadvertently placed
> on a non-
> local
> filesystem.
> o Silent component failover.
> o In the default case, if the posix component fails
> initialization,
> mmap will be selected.
> o The sysv component will only be queried for selection if it is
> placed before
> the mmap component (for example, -mca mpi_common_sm
> sysv,posix,mmap). In the
> default case, sysv will never be queried/selected.
> o Per some on-list discussion, now unlinking mmaped file in both mmap
> and posix
> components (see: "System V Shared Memory for Open MPI: Request for
> Community
> Input and Testing" thread).
> o Assuming local process homogeneity with respect to all utilized
> shared
> memory facilities. That is, if one local process deems a
> particular shared
> memory facility acceptable, then ALL local processes should be
> able to
> utilize that facility. As it stands, this is an important point
> because one
> process dictates to all other local processes which common sm
> component will
> be selected based on its own, local run-time test.
> o Addressed some of George's code reuse concerns.
>
> If there are no major objections by August 17th, I'll commit the code
> after the
> Tuesday morning conference call.
>
> Thanks!
>
> --
> Samuel K. Gutierrez
> Los Alamos National Laboratory
>
>
>
>
>
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