Hi Aneesh, On Fri, 17 Feb 2023 17:28:09 +0530 Aneesh Kumar K V <aneesh.kumar@xxxxxxxxxxxxx> wrote: > 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. Sounds very interesting. I think DAMON might be one another option, because it is designed to be easy to extended with various source of access information[1], and provides an abstraction layer for access temparature based memory management[2], namely Data Access Monitoring-based Operation Schemes (DAMOS). > 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. I also have experimented a DAMON-based THP optimization[3], which shown interesting results. Hope to discuss about this with you at LSF/MM. FYI, I also proposed an LSF/MM topic for DAMON[4]. [1] https://docs.kernel.org/mm/damon/design.html#configurable-layers [2] https://docs.kernel.org/mm/damon/api.html#c.damos [3] https://www.amazon.science/publications/daos-data-access-aware-operating-system [4] https://lore.kernel.org/damon/20230214003328.55285-1-sj@xxxxxxxxxx/ Thanks, SJ > > > 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 >
