Rank Process Not Bound to a Logical Core in a Hyper-threading Environment

Symptom

In a hyper-threading environment, the rank process is not bound to a logical core.

Possible Cause

• If the value of --bind-to is not specified, Hyper MPI uses the default value core. As a result, the rank process is bound to a physical core instead of a logical core.

--bind-to values include:

• core: binds the rank process to a physical core.

• hwthread: binds the rank process to a logical core.

• --bind-to is set to core. As a result, the rank process is bound to a physical core instead of a logical core.

Recovery Procedure

To bind the rank process to a logical core, set --bind-to to hwthread. The following gives an example:

mpirun -np 4 --bind-to hwthread osu_bcast

To distribute rank processes by logical core, set both --bind-to and --map-by to hwthread. The following gives an example:

mpirun -np 4 --map-by hwthread --bind-to hwthread osu_bcast