M P I _ C O M M _ W O R gen. count 0 L
M P I _ C O M M _ W O R gen. count 1 L
Figure 5.1: Example for a message sent and received in the same communi- cator however with di erent generation counts
Imagine for example the case, that process a posts a non-blocking receive operation from process b. Process b fails, before the data transmission can be finished. If the receive operation has been posted using a specified sender, the MPI-library can ’cancel’ this operation and declare the request to be invalid. However, if the receive operation has been posted using MPI ANY- SOURCE and no other process is sending a message which can match the posted receive, the application will deadlock.
avoided to the greates possible extent mode FTMPI MSG MODE CONT.
A possibility would be to give the user an at-
tribute after the recovery handles which the system
operation, which contains all request- could not dissolve, especially the ones
which have been posted using MPI
SOURCE. It is than the
responsibility of the user communication continue.