[mvapich-discuss] mvapich1 roadmap if any

[Dhabaleswar Panda]

> Dear All,
>
> I was looking at the change log of mvapich mvapich1 to be precises and i
> see the latest release available through the web was done Jan 2010, am i
> correct?  our end users prefer mvapich1 over mvapich2, somehow they believe
> that mvapich1 is performing faster for their data models and code.
>
> is there a different tuning needs to be done for mvapich2 to make it behave
> in a way backward compatible to mvapich1? what is the best resource other
> than the user guide to tuning mvapich for large clusters, large jobs around
> 128-512 nodes dual socket, hexacore.

Thanks for your note. For many applications, MVAPICH2 perform far better
than MVAPICH1. Many features, optimizations and tunings are available in
MVAPICH2 which are not available in MVAPICH1.

I have a few questions/feedbacks for you:

- Which version of MVAPICH2 you are using: 1.7 or 1.8a2 is recommended.

- What IB adapter you have - Mellanox or QLogic.

- Which interface you are using: OFA-IB-CH3 is the `default' and
  `recommended one' for Mellanox adapter. Similarly, PSM-CH3 is
  recommended one for QLogic adapters.

- Are you using `mpirun_rsh' (recommended one) for job launching?

- Are you using `LIMIC2' option for intra-node communication? This will
  provide you very good performance if your applications are using medium
  and large messages.

- Are you using the `Hybrid' feature of MVAPICH2? For large jobs
  (1K cores and higher), this feature should give you good performance
  and scalability with reduced memory footprint.

These are some general guidelines. In addition to the above points, it
will be good if you can let us know the configuration flags you are using
for configuring MVAPICH2 and any runtime parameters you are using when
running your job.

The user guide describes all these options and parameters.

I will initiate a separate e-mail thread with a copy to mvapich developers
list. If you provide more details on the application characteristics,
configuration settings, performance difference, etc., we will be happy to
provide additional feedback.

Best Regards,

DK



> regards
>
> Walid
>