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    SubjectRe: kernel BUG at mm/page-writeback.c:LINE!
    On Tue, Jan 12, 2021 at 2:44 AM Jan Kara <jack@suse.cz> wrote:
    >
    > On Fri 08-01-21 18:04:21, Linus Torvalds wrote:
    > >
    > > Oh, and Michael Larabel (of phoronix) reports that that one-liner does
    > > something bad to a few PostgreSQL tests, on the order of 5-10%
    > > regression on some machines (but apparently not others).
    >
    > Do you have more details? From my experience (we do regular pgbench runs
    > for various kernels in various configs in SUSE) PostgreSQL numbers tend to
    > be somewhat noisy and more dependent on CPU scheduling and NUMA locality
    > than anything else. But it very much depends on the exact config passed to
    > pgbench so that's why I'm asking...

    No, I don't really have many more details. I don't have things like
    raw numbers or exact configurations, but Michael has been very
    responsive if you ask, so if you are interested, just email him at
    Michael Larabel <Michael@michaellarabel.com>.

    It wasn't NUMA - apparently the machines he saw this on were just
    plain consumer setups, and his larger machines didn't actually show
    the effect. But yes, I suspect it was some scheduling artifact, and
    probably just fairly random noise from just changing the scheduling
    pattern a bit.

    Linus

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