Messages in this thread |  | | Subject | Re: [PATCH v2 3/5] mm: enlarge NUMA counters threshold size | From | kemi <> | Date | Wed, 20 Dec 2017 18:21:40 +0800 |
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On 2017年12月20日 18:12, Michal Hocko wrote: > On Wed 20-12-17 13:52:14, kemi wrote: >> >> >> On 2017年12月19日 20:40, Michal Hocko wrote: >>> On Tue 19-12-17 14:39:24, Kemi Wang wrote: >>>> We have seen significant overhead in cache bouncing caused by NUMA counters >>>> update in multi-threaded page allocation. See 'commit 1d90ca897cb0 ("mm: >>>> update NUMA counter threshold size")' for more details. >>>> >>>> This patch updates NUMA counters to a fixed size of (MAX_S16 - 2) and deals >>>> with global counter update using different threshold size for node page >>>> stats. >>> >>> Again, no numbers. >> >> Compare to vanilla kernel, I don't think it has performance improvement, so >> I didn't post performance data here. >> But, if you would like to see performance gain from enlarging threshold size >> for NUMA stats (compare to the first patch), I will do that later. > > Please do. I would also like to hear _why_ all counters cannot simply > behave same. In other words why we cannot simply increase > stat_threshold? Maybe calculate_normal_threshold needs a better scaling > for larger machines. >
Agree. We may consider that. But, unlike NUMA counters which do not effect system decision. We need consider very carefully when increase stat_threshold for all the counters for larger machines. BTW, this is another topic that we may discuss it in different thread.
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