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cr_run(1) [debian man page]

CR_RUN(1)							   User Commands							 CR_RUN(1)

NAME
cr_run - runs a subprocess with checkpoint library loaded. SYNOPSIS
cr_run [OPTIONS] COMMAND [ARGS] DESCRIPTION
cr_run takes an arbitrary command and runs it with the "LD_PRELOAD" environment variable set so that an appropriate shared library is loaded at program startup. Such a library must be loaded if you wish to take a checkpoint of the process with cr_checkpoint(1). cr_run assumes that BLCR's libraries (libcr*.so) can be found in the default library search path or via the "LD_LIBRARY_PATH" environment variable. You do not need to use cr_run if you explicitly link your application with -lcr (you may also need to modify your linker's search path with a -L directive, depending on the library's location), or if libcr.so or a related library is loaded by other libraries you have linked with (such as a checkpoint-ready MPI library), or by your system's parallel job startup script, etc. Check your system documentation for details. OPTIONS
-?,--help print a usage message and exit. --version print version information and exit. -- ends options processing. --omit causes executed process(es) to be omitted (rather than included) in any checkpoint taken. --run overrides any occurance of --omit earlier in the options (restoring the default behavior). BUGS
Because cr_run relies on the "LD_PRELOAD" environment variable, it is ineffective for statically-linked executables, and for setuid/gid programs. AUTHORS
Jason Duell, Paul Hargrove, and Eric Roman, Lawrence Berkeley National Laboratory. REPORTING BUGS
Bug reports may be filed on the web at http://mantis.lbl.gov/bugzilla. SEE ALSO
cr_checkpoint(1), cr_restart(1), Berkeley Lab Checkpoint/Restart May 2008 CR_RUN(1)

Check Out this Related Man Page

lamssi_cr(7)                                                    LAM SSI CR OVERVIEW                                                   lamssi_cr(7)

NAME
lamssi_checkpoint_restart - overview of LAM's MPI checkpoint / restart SSI modules DESCRIPTION
The "kind" for checkpoint / restart SSI modules is "cr". Specifically, the string "cr" (without the quotes) is the prefix that should be used with the mpirun command line with the -ssi switch. For example: mpirun -ssi cr blcr C my_mpi_program LAM/MPI can involuntarily checkpoint and restart parallel MPI jobs. Doing so requires that LAM/MPI was compiled with thread support and that back-end checkpointing systems are available at run-time. MPI jobs will have to run with at least MPI_THREAD_SERIALIZED support. If a job elects to run with checkpoint/restart support and an available cr module is found, the job's thread level will automatically be pro- moted to MPI_THREAD_SERIALIZED. See the User's Guide for more details. Checkpoint Phases LAM defines three phases for checkpoint / restart support in each MPI process: Checkpoint. When the checkpoint request arrives, before the actual checkpoint occurs. Continue. After a checkpoint has successfully completed, in the same process as the checkpoint was invoked in. Restart After a checkpoint has successfully completed, in a new / restarted process. The Continue and Restart phases are identical except for the process in which they are invoked -- the Continue phase is invoked in the same process as the Checkpoint phase was invoked. The Restart phase is only invoked in newly restarted processes. AVAILABLE MODULES
LAM currently has two cr modules: blcr and self. In order for an MPI job to be able to be checkpointed and restarted, all of its MPI SSI modules must support checkpoint/restart. Currently, this means using the crtcp RPI module or the gm RPI module when compiled with gm_get() support (see the User's Guide for more details). blcr CR Module The Berkeley Lab Checkpoint/Restart (BLCR) single-node checkpointer is a software system from Lawrence Berkeley Labs. See the project web page for more details: http://www.nersc.gov/research/ftg/checkpoint/. The blcr module has one SSI parameter: cr_blcr_priority blcr's default priority is 50. self CR Module The self module, when used with checkpoint/restart SSI modules, will invoke the user-defined functions to save and restore checkpoints. It is simply a mechanism for user-defined functions to be invoked at LAM's Checkpoint, Continue, and Restart phases. Hence, the only data that is saved during the checkpoint is what is written in the user's checkpoint function. No MPI library state is saved at all. As such, the model for the self module is slightly different than, for example, the blcr module. Specifically, the Restart function is not invoked in the same process image of the process that was checkpointed. The Restart phase is invoked during MPI_INIT of a new instance of the application (i.e., it starts over from main()). Multiple SSI parameters are available: cr_self_user_prefix Specify a string prefix for the name of the checkpoint, continue, and restart functions that should be invoked by LAM. That is, speci- fying "-ssi cr_self_user_prefix foo" means that LAM expects to find three functions at run-time: int foo_checkpoint(), int foo_con- tinue(), and int foo_restart(). This is a convenience parameter that can be used instead of the three parameters listed below. cr_self_user_checkpoint Name of the user function to invoke during the Checkpoint phase. cr_self_user_continue Name of the user function to invoke during the Continue phase. cr_self_user_restart Name of the user function to invoke during the Restart phase. If none of these parameters are specified and the self module is selected, it will use the default prefix lam_cr_self Finally, the usual priority SSI parameter is also available: cr_self_priority self's default priority is 25. SEE ALSO
lamssi(7), mpirun(1), LAM User's Guide LAM 7.1.4 July, 2007 lamssi_cr(7)
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