Bharata B Rao <bharata@xxxxxxx> writes: > On 10/28/2022 11:16 AM, Huang, Ying wrote: >> If my understanding were correct, you think the latency / bandwidth of >> these NUMA nodes will near each other, but may be different. >> >> Even if the latency / bandwidth of these NUMA nodes isn't exactly same, >> we should deal with that in memory types instead of memory tiers. >> There's only one abstract distance for each memory type. >> >> So, I still believe we will not have many memory tiers with my proposal. >> >> I don't care too much about the exact number, but want to discuss some >> general design choice, >> >> a) Avoid to group multiple memory types into one memory tier by default >> at most times. > > Do you expect the abstract distances of two different types to be > close enough in real life (like you showed in your example with > CXL - 5000 and PMEM - 5100) that they will get assigned into same tier > most times? > > Are you foreseeing that abstract distance that get mapped by sources > like HMAT would run into this issue? Only if we set abstract distance chunk size large. So, I think that it's better to set chunk size as small as possible to avoid potential issue. What is the downside to set the chunk size small? Best Regards, Huang, Ying
