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From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2005-07-22 11:31:56

While wrapping my head around mind-bending shmem memory structures and
waiting for compiles over the past few days, I revamped the MCA param
API to both do some new things and fix things that everyone has been
working around:

- Tim has always added 2 extra "register" functions to every component
so that he can register a parameter and look up its value at the same
time. This (register + lookup) action is now handled in one MCA param
API function.

- You can now specify a "help message" for each MCA parameter
describing what it is and what valid values are. Then, when you run
"ompi_info", each parameter is labeled with its help message -- makes
this stuff *much* more useful to the user.

- You can have "read-only" MCA parameters. For example, the gm BTL can
advertise what version of the GM library the component was linked
against (very, very helpful for sysadmins and debugging).

I'll show everyone the new API calls next week (I need to get a code
review before I commit all this stuff). I'm leaving in the old API
calls for backwards compatibility so that the trunk doesn't break, but
I will be encouraging everyone to move their components over to use the
new API calls in the near future (this will really help reduce the
number of questions that we get about MCA params).

{+} Jeff Squyres
{+} The Open MPI Project