PowerPC architecture (POWER10) supports a Hot/Cold page tracking facility that provides access counter and access affinity details at configurable page size granularity [1]. I have been looking at using this counter in different areas of the kernel such as 1) Page reclaim/demotion 2) THP utilization 3) Page promotion. I have done some MGLRU integration and would like to discuss the observation with the rest of the community. It is still not clear what are the best ways to integrate these hardware counters in the Linux kernel. Attached is the performance graph showing how the mongodb/ycsb benchmark performs when using hardware counters with MGLRU aging. An early RFC version of the code can be found at https://github.com/kvaneesh/linux/commit/b472e2c8080823bb4114c286270aea3e18ffe221 . I also expect we can get some numbers w.r.t THP usage before the conference. X axis is the amount of memory that I am removing from the system so that I can force more memory reclaims. The total memory available is 50GB/single NUMA node/64 CPUs,40GB database with 40GB cache configuration. [1] https://hc32.hotchips.org/assets/program/conference/day1/HotChips2020_Server_Processors_IBM_Starke_POWER10_v33.pdf
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