On Fri, Feb 17, 2023 at 3:58 AM 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. Not sure whether you are aware of this patchset: https://lore.kernel.org/linux-mm/20230208073533.715-1-bharata@xxxxxxx/ ARM64 has SPE which provides similar functionality. So I hope a common framework could be provided to hide the hardware details. > > 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
