Processor binding for parallel jobs

By default, there is no processor binding.

For multi-host parallel jobs, LSF sets two environment variables ($LSB_BIND_JOB and $LSB_BIND_CPU_LIST) but does not attempt to bind the job to any host even if you enable the processor binding.

Resizable jobs

Adding slots to or removing slots from a resizable job triggers unbinding and rebinding of job processes. Rebinding does not guarantee that the processes can be bound to the same processors they were bound to previously.

If a multi-host parallel job becomes a single-host parallel job after resizing, LSF does not bind it.

If a single-host parallel job or sequential job becomes a multi-host parallel job after resizing, LSF does not bind it.

After unbinding and binding, the job CPU affinity is changed. LSF puts the new CPU list in the LSB_BIND_CPU_LIST environment variable and the binding method to LSB_BIND_JOB environment variable. And it is the responsibility of the notification command to tell the job that CPU binding has changed.