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| | This page describes how to use the checkpointing capability of MPICH. | | This page describes how to use the checkpointing capability of MPICH. |
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| − | == Configuration ==
| + | BLCR is no longer support in latest MPICH. |
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| − | First, you need to have BLCR version 0.8.2 or later installed on your
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| − | machine. If it's installed in the default system location, add the
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| − | following two options to your configure command:
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| − | --enable-checkpointing
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| − | --with-hydra-ckpointlib=blcr
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| − | If BLCR is not installed in the default system location, you'll need
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| − | to tell MPICH's configure where to find it. You might also need to
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| − | set the LD_LIBRARY_PATH environment variable so that BLCR's shared
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| − | libraries can be found. In this case add the following options to
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| − | your configure command:
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| − | --enable-checkpointing
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| − | --with-hydra-ckpointlib=blcr
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| − | --with-blcr=<BLCR_INSTALL_DIR>
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| − | LD_LIBRARY_PATH=<BLCR_INSTALL_DIR>/lib
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| − | where <BLCR_INSTALL_DIR> is the directory where BLCR has been
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| − | installed (whatever was specified in --prefix when BLCR was
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| − | configured).
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| − | After it's configured compile as usual (e.g., make; make install).
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| − | Note, checkpointing is only supported with the Hydra process manager.
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| − | == Verifying Checkpointing Support ==
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| − | Make sure MPICH is correctly configured with BLCR. You can do this
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| − | using:
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| − | mpiexec -info
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| − | This should display 'BLCR' under 'Checkpointing libraries available'.
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| − | == Checkpointing the Application ==
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| − | There are two ways to cause the application to checkpoint. You can ask
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| − | mpiexec to periodically checkpoint the application using the mpiexec
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| − | option -ckpoint-interval (seconds):
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| − | mpiexec -ckpointlib blcr -ckpoint-prefix /tmp/app.ckpoint \
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| − | -ckpoint-interval 3600 -f hosts -n 4 ./app
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| − | | |
| − | Alternatively, you can also manually force checkpointing by sending a
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| − | SIGUSR1 signal to mpiexec.
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| − | The checkpoint/restart parameters can also be controlled with the
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| − | environment variables HYDRA_CKPOINTLIB, HYDRA_CKPOINT_PREFIX and
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| − | HYDRA_CKPOINT_INTERVAL.
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| − | To restart a process:
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| − | mpiexec -ckpointlib blcr -ckpoint-prefix /tmp/app.ckpoint -f hosts -n 4 -ckpoint-num <N>
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| − | where <N> is the checkpoint number you want to restart from.
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| − | ----
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| | Notes on the implementation of checkpointing on Nemesis can be found [[Checkpointing_implementation|here]]. | | Notes on the implementation of checkpointing on Nemesis can be found [[Checkpointing_implementation|here]]. |
