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Subject: [OMPI devel] RFC: Drop all mpirun single-dash multi-letter CLI options (except -np)
From: Jeff Squyres (jsquyres) (jsquyres_at_[hidden])
Date: 2014-01-07 16:49:13


WHAT: Drop mpirun single-dash CLI options such as -bynode (but keep the double-dash equivalents, like --bynode)

WHY: It's a well-established de facto CLI option standard:
  "-" is used for single-letter options
  "--" is used for tokenized options

WHERE: probably mostly in orte/tools/orterun

WHEN: 1.9

TIMEOUT: Teleconf, Tuesday 21 Jan 2014

MORE DETAIL:

We've supported single- and double-dash variants of many mpirun options for several years (e.g., --bynode and -bynode). With the exception of "-np", there's really no reason we should support the single-dash versions ("-np" is pretty universally expected in the MPI/HPC world; I don't think we'll ever be able to get rid of it).

Let's deprecate all single-dash options (except -np) in 1.7.5/1.8 and eliminate them in 1.9. Specifically, let's do something like this in 1.7.5:

-----
$ shell mpirun -bynode -np 4 a.out
------------------------------------------------------------------------
You used the "-bynode" option to mpirun, which, although it still functions
as you would expect it to, is now deprecated. The exactly-equivalent "--bynode"
option replaces the "-bynode" option.

 *** NOTE THAT -bynode OPTION WILL DISAPPEAR IN A FUTURE VERSION OF OPEN MPI! ***

To be compatible with future versions of Open MPI, use the "--bynode" option.

If you can't easily change your mpirun command line, then you can set the MCA
parameter orterun_i_promise_to_update_my_cli_options_before_ompi_1_9 to 1,
which will suppress this message.
------------------------------------------------------------------------
-----

This gives the user two clear options:

1. Update from -foo to --foo to be forward compatible
2. Set an MCA parameter to suppress the message, but risk not being forward compatible

Then, on trunk/v1.9, we remove all the single-dash options.

Comments?

-- 
Jeff Squyres
jsquyres_at_[hidden]
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