[Mpi3-ft] Quiescence Interface

[Greg Bronevetsky]

At 07:21 AM 1/22/2009, Josh Hursey wrote:
>I have updated the Quiescence Interface proposal on the wiki:
>   https:// svn.mpi-forum.org/trac/mpi-forum-web/wiki/Quiescence
>
>I am interested in questions and comments from the group regarding the
>interface, and use-cases. The primary use-case is for application
>initiated checkpoint/restart, but the semantics of the proposed API
>likely also open doors to other use-cases.
>
>Let me know what you think.
I like that this proposal is more detailed than our previous 
discussions but I don't think that my major concern has been 
addressed yet. The key text in the proposal is "all of the in-flight 
messages have been accounted for in the specified comm". What does 
"accounted for" mean? Does the relevant message information go into 
some sort of buffer? Is it on the network card? What semantics are we 
actually guaranteeing here? I'm comfortable with the idea that the 
semantics are application dependent and this is just a standard API 
for applications to use to access these semantics but in that case 
the value of having this API is significantly reduced.

Greg Bronevetsky
Post-Doctoral Researcher
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Lawrence Livermore National Lab
(925) 424-5756
bronevetsky1 at llnl.gov