Hi Josh, I vote for MPI_COMM_VALIDATE. Howard Josh Hursey wrote:
While preparing the EuroMPI poster last night, I noticed that the naming of the agreement protocol collective is still somewhat problematic. I think this is what Darius mentioned in a previous email, but I did not get it until I was converting some of the examples.
The semantics of the agreement protocol collective are pretty solid: Uniform agreement of the set of failures in a communicator, and re-enable collective operations excluding the agreed upon set of failures.
However the new function name (MPI_Comm_reenable_collectives) only addresses the latter part of the semantics. Commonly people will be using this routine to answer questions like: "Are there any failures in this communicator?" "Are there any new failures in this communicator?" "Is Rank X failed in this communicator?"
Those questions focus more on the first part of the semantic. So it seems to me that we need to adjust the name of this function to reflect the full semantics of the operation.
----- A rough example ----- MPI_Comm_reenable_collectives(comm, &group[0]); do { .. Do work .. MPI_Comm_reenable_collectives(comm, &group[1]); if( group[0] != group[1] ) { /* New failures detected */ group[0] = group[1]; continue; /* retry) } else { break; /* no new failures - recovery block OK */ } } while( 1 ); ----- A rough example -----
I don't have a good suggestion at this point, but it is something we should address. Darius previous suggested the following: MPI_COMM_VALIDATE MPI_COMM_REPAIR MPI_COMM_RESTORE MPI_COMM_RECONCILE MPI_COMM_CORRELATE MPI_COMM_NORMALIZE
I would like to reserve 'Repair' and 'Restore' for the process recovery proposal. I am leading towards MPI_Comm_validate.
Validate implies that we are making a declaration of the accuracy or soundness of something (in this case the communicator and failed set). So that seems to give us 'agreement' and to some degree implies 'ok for collectives'.
What to folks think?
-- Josh
-- Howard Pritchard Software Engineering Cray, Inc.