Generally NUMA doesn't matter for "make" workloads so this as all academic, but that being said no, this isn't how modern CPUs work. When you start two unrelat

Generally NUMA doesn't matter for "make" workloads so this as all academic, but that being said no, this isn't how modern CPUs work. When you start two unrelated processes one after the other (such as multiple compile steps) that operate on some of the same in-memory assets (files, things being sent over a pipe etc.) they're not just going to be in the main RAM, but also L1-3 cache, and the RAM itself may be segmented under the hood (even if it's presented to you as one logical address space). Thus you can benefit from pinning certain groups of tasks to a given CPU/memory space if you know the caches can be re-used without the OS having to transfer the memory to another CPU's purview, or re-populate the relevant caches from RAM.