CDA SC510 User's Guide download pdf (Page 49)

D2.1.4 IST-033576

B.5 Checkpointing/restarting an MPI application

The best source of information on dealing with any BLCR-aware MPI implemen-

tation is the documentation provided with the MPI. However, here are some hints

that may be helpful.

B.5.1 Checkpoint/restart with LAM/MPI

• See the the LAM/MPI documentation for the most detailed info on using

LAM/MPI with BLCR.

• When building your own LAM/MPI, do NOT conﬁgure LAM to debug

mode, i.e. do not pass –with-debug to LAM’s conﬁgure script.

• To start a checkpointable LAM/MPI application, simply run it with the reg-

ular LAM mpirun launcher:

% mp irun C h e l l o _ m p i

Note: you may need to start up the LAM environment ﬁrst by running lam-

boot before starting your application.

• To checkpoint the entire MPI application (across all nodes and processes),

simply run

% l a m c h e c k p o i n t 12305

Where ’12305’ is the process ID of the mpirun command. Do not pass the

pid of your MPI executable: when mpirun is checkpointed, it automatically

takes care of transitively checkpointing all of the processes involved in the

MPI job.

• To restart your MPI job, simply run the following against the mpirun pro-

cess’s context ﬁle:

% l a m r e s t a r t c o n t e x t . 12 3 0 5

All processes in the MPI job will be restarted as they were at checkpoint

time.

• By default, LAM will place the checkpoint ﬁles for the MPI application

processes in your $HOME directory. If you want them to be placed else-

where, override the default location in the ﬁlesystem where LAM stores

checkpoints.

47/49 XtreemOS–Integrated Project

1 2 ... 44 45 46 47 48 49 50 51

No comments

CDA SC510 User's Guide Page 49