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Subject: Re: [OMPI devel] [OMPI svn-full] svn:open-mpi r28911 - trunk
From: Tim Mattox (timattox_at_[hidden])
Date: 2013-07-22 15:31:48


Should that now read "There are two network models available", not
"three"? :-)

On Mon, Jul 22, 2013 at 3:16 PM, <svn-commit-mailer_at_[hidden]> wrote:

> Author: hjelmn (Nathan Hjelm)
> Date: 2013-07-22 15:16:59 EDT (Mon, 22 Jul 2013)
> New Revision: 28911
> URL: https://svn.open-mpi.org/trac/ompi/changeset/28911
>
> Log:
> Update README with information about uGNI and vader BTLs. Also remove
> references to the csum pml.
>
> cmr=v1.7.3:reviewer=jsquyres
>
> Text files modified:
> trunk/README | 34 ++++++++++++++++++----------------
> 1 files changed, 18 insertions(+), 16 deletions(-)
>
> Modified: trunk/README
>
> ==============================================================================
> --- trunk/README Mon Jul 22 13:53:58 2013 (r28910)
> +++ trunk/README 2013-07-22 15:16:59 EDT (Mon, 22 Jul 2013)
> (r28911)
> @@ -484,10 +484,10 @@
> Network Support
> ---------------
>
> -- There are three MPI network models available: "ob1", "csum", and
> - "cm". "ob1" and "csum" use BTL ("Byte Transfer Layer") components
> - for each supported network. "cm" uses MTL ("Matching Tranport
> - Layer") components for each supported network.
> +- There are three MPI network models available: "ob1", and "cm". "ob1"
> + uses BTL ("Byte Transfer Layer") components for each supported network.
> + "cm" uses MTL ("Matching Tranport Layer") components for each supported
> + network.
>
> - "ob1" supports a variety of networks that can be used in
> combination with each other (per OS constraints; e.g., there are
> @@ -503,12 +503,8 @@
> - SCTP
> - uDAPL
> - Cisco usNIC
> -
> - - "csum" is exactly the same as "ob1", except that it performs
> - additional data integrity checks to ensure that the received data
> - is intact (vs. trusting the underlying network to deliver the data
> - correctly). csum supports all the same networks as ob1, but there
> - is a performance penalty for the additional integrity checks.
> + - uGNI (Cray Gemini, Ares)
> + - vader (xpmem)
>
> - "cm" supports a smaller number of networks (and they cannot be
> used together), but may provide better better overall MPI
> @@ -521,14 +517,12 @@
>
> Open MPI will, by default, choose to use "cm" when the InfiniPath
> PSM or the Mellanox MXM MTL can be used. Otherwise, "ob1" will be
> - used and the corresponding BTLs will be selected. "csum" will never
> - be selected by default. Users can force the use of ob1 or cm if
> - desired by setting the "pml" MCA parameter at run-time:
> + used and the corresponding BTLs will be selected. Users can force
> + the use of ob1 or cm if desired by setting the "pml" MCA parameter
> + at run-time:
>
> shell$ mpirun --mca pml ob1 ...
> or
> - shell$ mpirun --mca pml csum ...
> - or
> shell$ mpirun --mca pml cm ...
>
> - MXM is a MellanoX Messaging library utilizing full range of IB
> @@ -546,6 +540,9 @@
> Although the usNIC is accessed via the OpenFabrics / Verbs API
> stack, this BTL is specific to the Cisco usNIC device.
>
> +- uGNI is a Cray library for communicating over the Gemini and Ares
> + interconnects.
> +
> - The OpenFabrics Enterprise Distribution (OFED) software package v1.0
> will not work properly with Open MPI v1.2 (and later) due to how its
> Mellanox InfiniBand plugin driver is created. The problem is fixed
> @@ -598,7 +595,7 @@
> resulting in lower performances in case of non-contiguous
> data-types.
>
> - The "ob1" and "csum" PMLs and BTL components use Open MPI's internal
> + The "ob1" PML and BTL components use Open MPI's internal
> on-node shared memory and process loopback devices for high
> performance. The BTL interface allows multiple devices to be used
> simultaneously. For the MX BTL it is recommended that the first
> @@ -624,6 +621,11 @@
>
> See http://runtime.bordeaux.inria.fr/knem/ for details on Knem.
>
> +- XPMEM is used by the vader shared-memory BTL when the XPMEM
> + libraries are installed. XPMEM allows Open MPI to map pages from
> + other processes into the current process' memory space. This
> + allows single-copy semantics for shared memory without the need
> + for a system call.
>
> Open MPI Extensions
> -------------------
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>

-- 
Tim Mattox, Ph.D. - I'm a bright... http://www.the-brights.net/
 timattox_at_[hidden] || tmattox_at_[hidden]