[mvapich-discuss] Listing of "hidden" MV2 environment variables?

[Hari Subramoni]

Hello Matt,

Good to know that the problem got solved by using blocking mode. Would it
be possible for you to give us a reproducer so that we can try to debug the
problem locally?

We are continually working to expose the environment varibales in the
MVAPICH2 code base through the MV2_SHOW_ENV_INFO option. We hope to have
this option display all enviroment variables in one of our future releases.

Thx,
Hari.

On Tue, Jan 20, 2015 at 12:09 PM, Thompson, Matt (GSFC-610.1)[SCIENCE
SYSTEMS AND APPLICATIONS INC] <matthew.thompson at nasa.gov> wrote:

> All,
>
> In my recent attempts to diagnose and workaround this issue [1]:
>
>  http://mailman.cse.ohio-state.edu/pipermail/mvapich-discuss/
>> 2015-January/005296.html
>>
>
> I've been twiddling various MV2_ environmental knobs by looking at the
> output of MV2_SHOW_ENV_INFO=2 and I eventually realized that that setting
> does not show all environment variables.
>
> For example, it turns out that, at least for one case (the above 336
> process one), MV2_USE_BLOCKING=1 seems to workaround the issue.
>
> However, in a "stock option" run of MVAPICH2 2.1rc1--where
> MV2_USE_BLOCKING=0 is the default setting--MV2_USE_BLOCKING does not show
> up in the listing of MV2_SHOW_ENV_INFO=2. It's only shown if it is toggled.
>
> So, I was wondering, does anyone have a listing of what knobs are turnable
> in MVAPICH2 (say in the User's Guide) but aren't included in
> MV2_SHOW_ENV_INFO=2?
>
> Or, perhaps, is there a higher value of MV2_SHOW_ENV_INFO that shows them
> (a la I_MPI_DEBUG in Intel MPI)? I tried 3 but nothing really happened save
> the =1 prints.
>
> (Note: Some further testing seems to show that it's actually
> MV2_USE_SHARED_MEM=0 set by MV2_USE_BLOCKING=1 that's helping. More to
> test!)
>
> Matt
>
> [1] Update: looks like changing MV2_SMP_NUM_SEND_BUFFER and
> MV2_EAGERSIZE_1SC[2] to their Westmere/DDR values do not always solve the
> problem. On 336 cores, it seems to be more reliably halting at all times.
>
> [2] Does anyone know what MV2_EAGERSIZE_1SC does? It does not seem to
> exist in the User's Guide.
>
> --
> Matt Thompson          SSAI, Sr Software Test Engr
> NASA GSFC, Global Modeling and Assimilation Office
> Code 610.1, 8800 Greenbelt Rd, Greenbelt, MD 20771
> Phone: 301-614-6712              Fax: 301-614-6246
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>
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