On Jun 14, 2010, at 5:26 AM, Nguyen Toan wrote: > Hi all, > I have a MPI program as follows: > ------------------- > int main(){ > MPI_Init(); > ...... > for (i=0; i<10000; i++) { > my_atomic_func(); > } > ... > MPI_Finalize(); > return 0; > } > -------------------- > > The runtime of this program mainly involves in running the loop and > my_atomic_func() takes a little bit long. > Here I want my_atomic_func() to be operated atomically, but the timing of > checkpointing (by running ompi-checkpoint command) may be in the middle of > my_atomic_func() operation and hence ompi-restart may fail to restart > correctly. > > So my question is: > + At the checkpoint time (executing ompi-checkpoint), is there a way to let > OpenMPI wait until my_atomic_func() finishes its operation?
We do not currently have an external function to declare a critical section during which a checkpoint should not be taken. I filed a ticket to make one available. The link is below if you would like to follow its progress: https://svn.open-mpi.org/trac/ompi/ticket/2487 I have an MPI Extension interface for C/R that I will be bringing into the trunk in the next few weeks. I should be able to extend it to include this feature. But I can't promise a deadline, just that I will update the ticket when it is available. In the mean time you might try to use the BLCR interface to define critical sections. If you are using the C/R thread then this may work (though I have not tried it): cr_enter_cs() cr_leave_cs() > + How does ompi-checkpoint operate to checkpoint MPI threads? We depend on the Checkpoint/Restart Service (e.g., BLCR) to capture the whole process image including all threads. So BLCR will capture the state of all threads when we take the process checkpoint. -- Josh > > Regards, > Nguyen Toan > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users