[blattimwind]

NUMA means "(Explicitly) Non-Uniform Memory Access"; this means that some cores have easier (lower latency, higher bandwidth) access to some memory regions than others.

In practice this means that memory controllers are partitioned amongst groups of cores, with some slower and often otherwise busy interconnect between those groups.

The software implication is that if task X uses some bit of memory a lot, then that bit of memory better be node-local, i.e. easy to access for the core where task X is running.