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 1028 Building 451 Lawrence Livermore National Lab (925) 424-5756 [email protected]