[lkml]   [2012]   [Sep]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: 20% performance drop on PostgreSQL 9.2 from kernel 3.5.3 to 3.6-rc5 on AMD chipsets - bisected
    On Fri, Sep 14, 2012 at 2:27 PM, Borislav Petkov <> wrote:
    > as Nikolay says below, we have a regression in 3.6 with pgbench's
    > benchmark in postgresql.
    > I was able to reproduce it on another box here and did a bisection run.
    > It pointed to the commit below.

    Ok. I guess we should just revert it. However, before we do that,
    maybe Mike can make it just use the exact old semantics of
    select_idle_sibling() in the update_top_cache_domain() logic.

    Because the patch in question seems to do two things:
    (a) cache the "idle_buggy" logic, so that we don't have those costly loops
    (b) change it to do that "left-right" thing.

    and that (b) thing may be what causes a regression for you.

    So my gut feel is that the patch was wrong to begin with, exactly
    because it did two independent changes. It *should* have treated those
    two issues as independent changes and separate commits.

    Maybe I'm mis-reading it. Mike? Peter?


     \ /
      Last update: 2012-09-15 00:41    [W:0.046 / U:9.480 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site