Messages in this thread | | | Date | Thu, 4 Aug 2022 17:30:33 +0800 | Subject | Re: [RFC PATCH V4 1/1] mm: add last level page table numa info to /proc/pid/numa_pgtable | From | haoxin <> |
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在 2022/8/4 下午4:12, David Hildenbrand 写道: > 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. Ok, thanks for your suggestion, I will implement it in the next version.
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