Messages in this thread | | | Date | Thu, 4 Aug 2022 10:12:00 +0200 | Subject | Re: [RFC PATCH V4 1/1] mm: add last level page table numa info to /proc/pid/numa_pgtable | From | David Hildenbrand <> |
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On 04.08.22 10:04, haoxin wrote: > > 在 2022/8/1 下午9:28, David Hildenbrand 写道: >> On 01.08.22 14:17, Xin Hao wrote: >>> In many data center servers, the shared memory architectures is >>> Non-Uniform Memory Access (NUMA), remote numa node data access >>> often brings a high latency problem, but what we are easy to ignore >>> is that the page table remote numa access, It can also leads to a >>> performance degradation. >> Let me try rewriting: >> >> " >> Many data center servers employ Non-Uniform Memory Access (NUMA) >> architectures. Remote numa memory access results in high latency. While >> memory placement is one issue, sub-optimal page table placement can also >> result in surprise performance degradation. >> " > Thanks, it reads more clearly. > >>> So there add a new interface in /proc, This will help developers to >>> get more info about performance issues if they are caused by cross-NUMA. >> >> Why do we only care about "last level page table", why not about the others? >> >> IMHO, we could emit something like "0, 1, 3, 0" instead for a given user >> space address, showing the NUMA node the page table belongs to from >> highest to lowest page table level. > > I have planned to implement the PTE page table in this version first, > and then support other page tables in the next patch later.
If there are plans, let's do it all at once, to get a good and single interface to expose that information.
-- Thanks,
David / dhildenb
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