[mvapich-discuss] VIADEV_CLUSTER_SIZE

[Matthew Koop]

Mark,

It depends on what device you are using. For the OpenFabrics/Gen2 device,
that parameter is not available since it is no longer needed. The library
automatically limits resources according to job size as required. Other
scalability features such as SRQ and on-demand connection setup remove
the need for that variable.

We'll update that entry in the user guide to make it apparent that
variable is only used in the VAPI device.

For any of the variables, they can be set either in the mvapich.conf file
or specified at runtime. e.g.

mpirun_rsh -np 2 m0 m1 VIADEV_USE_SHARED_MEM=0 ./a.out

Let us know if you have any other questions or if this didn't help.

Thanks,

Matt

On Wed, 27 Jun 2007, Mark Potts wrote:

> Hi,
>     I see a description of an attractive MVAPICH parameter in the 0.9.9
>     User Guide: VIADEV_CLUSTER_SIZE with possible values of SMALL,
>     MEDIUM, LARGE, and AUTO.  There is no matching default for this
>     parameter contained in the mvapich.conf file.
>
>     Is this parameter truly implemented, as an app run time parameter,
>     in MVAPICH 0.9.9 and if so how/where does its default value get
>     assigned?
>
>              regards,
> --
> ***********************************
>  >> Mark J. Potts, PhD
>  >>
>  >> HPC Applications Inc.
>  >> phone: 410-992-8360 Bus
>  >>        410-313-9318 Home
>  >>        443-418-4375 Cell
>  >> email: potts at hpcapplications.com
>  >>        potts at excray.com
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