Gregory Price <gourry@xxxxxxxxxx> writes: > On Sun, Dec 22, 2024 at 03:21:32PM +0800, Huang, Ying wrote: >> Hyeonggon Yoo <hyeonggon.yoo@xxxxxx> writes: >> >> > On this server, ideally weighted interleaving should be configured >> > within a socket (e.g. local NUMA node + local CXL node) because >> > weighted interleaving does not consider the bandwidth when accessed >> > from a remote socket. >> >> If multiple sockets are considered, what is the best behavior? >> >> The process may be cross-socket too. So, we will need to use >> set_mempolicy() to bind tasks to sockets firstly. Then, it may be >> better to use per-task weights. >> > > If we want to revisit this, we might be able to make task-local weights > work without a new syscall, but the use case was not clear enough which > is why it was soft-nak'd originally. Yes. That is doable. However, the challenge is lacking use cases. I guess that we can wait for more use cases? > vma-local weights are arguably more usable, but require the task to be > numa-aware and probably require a new mempolicy syscall because mbind > has no remaining arguments. > > recall my original testing results from stream: > https://lore.kernel.org/linux-mm/20240202170238.90004-1-gregory.price@xxxxxxxxxxxx/ > > Stream Benchmark (vs DRAM, 1 Socket + 1 CXL Device) > Default interleave : -78% (slower than DRAM) > Global weighting : -6% to +4% (workload dependant) > Targeted weights : +2.5% to +4% (consistently better than DRAM) --- Best Regards, Huang, Ying
