ULFM Fault Tolerance (slice 3: shrink)

[abouteiller]

Problem

The monolithic ULFM proposal has been split in morsels so that the MPI Forum can focus on individual topics.

Main topic issue
#20

Proposal

The third topic slice contains the following concepts for communicators:

• MPI_COMM_SHRINK

Changes to the Text

Addition of an FT chapter containing the proposed constructs

Impact on Implementations

Implementations optionally to implement fault tolerance.
Implementations to add procedures MPI_COMM_SHRINK (implementations that do not support FT can provide stubs that are not fault tolerant based on MPI_COMM_DUP).

Impact on Users

Users can repair communicators as needed to use collective and process respawning after a fault.

References and Pull Requests

https://github.com/mpi-forum/mpi-standard/pull/877