Links for 2015-03-23

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One Comment

  1. Nix
    Posted March 24, 2015 at 13:12 | Permalink

    That THP post is a bit misleading. Transparent hugepages do not change all allocations to use huge pages: instead, they wait for the application to request them and have a background daemon searching for ranges of page that might benefit (roughly, are virtually contiguous, have the same protection permissions and have been around a while). The effect is ideally meant to be as if the underlying page size was larger, while retaining compatibility with things that expect smaller pages (i.e. almost everything).

    It doesn’t quite work like that yet. I use THP (because I run big VMs and big compiles and THP helps a lot in those workloads), but for other workloads, particularly swap-bound ones, they are still definitely problematic and can cause big slowdowns rather than 5-10% speedups :(