Using the ParaStation5 queuing facility
a predefined node list. If not defined, all currently known nodes are taken into account. Also, the variables PSI_NODES_SORT, PSI_LOOP_NODES_FIRST, PSI_EXCLUSIVE and PSI_OVERBOOK are observed. Based on these variables and the list of currently active processes, a sorted list of nodes is constructed, defining the final node list for this new task.
Beside this environment variables, node reservations for users and groups are also observed. See psiadmin(1).
In addition, only available nodes will be used to start up processes. Currently not available nodes will be ignored.
Obeying all these restrictions, the processes constructing a parallel task will be spawned on the nodes listed within the final node list. For SMP systems, all available CPUs (cores) on this node may be used for consecutive ranks, depending on the environment variable PSI_LOOP_NODES_FIRST.
For administrative tasks not requiring a dedicated CPU (core), e.g. processes spawned using pssh, other strategies take place. As this type of processes are intended to run on dedicated nodes, predefined by the user, the described procedure will be circumvented and the processes will be run on the
For a detailed discussion of placing processes within ParaStation5, please refer to process placement(7), ps_environment(5), pssh(8) and mpiexec(8).
5.4. Using the ParaStation5 queuing facility
ParaStation is able to queue task start requests if required resources are currently in use. This queuing facility is disabled by default. It can be enabled by each user independently. All requests of all users are held within one queue and managed on a
For details, refer to ParaStation5 User's Guide.
5.5. Exporting environment variables for a task
ParaStation by default exports only a limited set of environment variables to newly spawned processes, like HOME, USER, SHELL or TERM.
Additional variables can be exported using PSI_EXPORTS.
For a complete list of environment variables known to and exported automatically by ParaStation, refer to ps_environment(5) .
For more details, refer to ParaStation5 User's Guide.
5.6. Using non-ParaStation applications
It is possible to run programs linked with 3rd party MPI libraries within the ParaStation environment. Currently supported MPI1 compatible libraries are:
•MPIch using ch_p4 (mpirun_chp4)
•MPIch using GM (mpirun_chgm)
•InfiniPath
•MVAPIch (mpirun_openib)
•QsNet MPI (mpirun_elan)
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