What does `numactl --localalloc` do?

--localalloc will force memory allocation to come from the local pool for the node the process is running on, whatever node that may be.

To force bind to a specific processor, the --physcpubind option must be specified. When used in conjunction with localalloc, it'll force a process to run on a specified node and only draw memory from that node.

--preferred tells it to allocate from a specific node if possible, but use remote memory if not.