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Mapping options and modifiers

This topic collection explains some of the options that are available for mapping and includes examples. Ranking and binding options are sometimes shown in the mapping examples.

--map-by unit option
Learn when and how to use the --map-by unit option.

--map-by slot option
Mapping by slot resembles mapping by an actual hardware unit within the hosts, but each slot is associated with the whole host. The slot is essentially an imaginary hardware unit that exists in a certain number on each host.

--map-by unit:PE=n and --map-by slot:PE=n options
This option is used to bind n cores to each process.

--map-by ppr:n:unit and --map-by ppr:n:unit:pe=n options
Learn how and when to use --map-by ppr:n:unit and --map-by ppr:n:unit:pe=n options.

--map-by dist:span option (adapter affinity)
Learn when and how to use the --map-by dist:span option (adapter affinity).

Parent topic: Managing IBM Spectrum MPI process placement and affinity
Top level index: IBM Spectrum MPI