On Thursday, 23 September 2021 17:32:46 BST Charlotte Delenk wrote: > On 9/23/21 18:30, Grant Taylor wrote: > > > On 9/23/21 4:39 AM, Miles Malone wrote: > > > >> You'd need NUMA if you had a NUMA machine. In current context, that > >> would be either a) a dual socket system, b) an amd threadripper, or > >> c) some of the really high core xeons. If your motherboard doesnt > >> have certain memory banks allocated to certain processors or cores, > >> you're probably not running a NUMA machine. > > > > > > > > Will a kernel without NUMA support boot and run on a system that has a > > NUMA architecture? > > > > > > > > If it will boot and run, does it simply do so in a sub-optimal way? > > Pure speculation for this one but if it works it's probably only going > to detect part of the memory and some of the devices and one cpu, since > the other resources are physically connected to the other cpus. > > > > > > > Flipping the coin on the other side, is there any negative effect > > (other than kernel size / lines of code / attack surface) for having > > NUMA support enabled on a non-NUMA system? > > There is no meaningful downside to leaving it enabled, it's enabled in > many distribution kernels for a reason.
I've booted a kernel with no NUMA config, and it seems to run fine on this single-socket Ryzen motherboard. I just get the one entry in dmesg: $ dmesg | grep -i numa [ 0.297998] pci_bus 0000:00: on NUMA node 0 That's it. I'm running five BOINC projects, some of which run on vbox, so on this motherboard it seems clear that I don't need NUMA. -- Regards, Peter.
