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    SubjectRe: Poor PostgreSQL scaling on Linux 2.6.25-rc5 (vs 2.6.22)
    On Sun, Mar 16, 2008 at 10:16:36PM -0700, Ray Lee wrote:
    > On Sun, Mar 16, 2008 at 5:44 PM, Nick Piggin <> wrote:
    > > I don't see how it is really helpful for interactive processes either.
    > > By definition, if they are not CPU bound, then they should be run
    > > quite soon after waking up; if they are CPU bound, then reducing
    > > efficiency by increasing context switches is effectively going to
    > > increase their latency anyway.
    > How? Are you saying that switching the granularity to, say, 25ms, will
    > *decrease* the latency of interactive tasks?
    > And the efficiency we're talking about reducing here is due to the
    > fact that tasks are hitting cold caches more times per second when the
    > granularity is smaller, correct? Or are you concerned by another
    > issue?
    > > Can this be changed by default, please?
    > Not without benchmarks of interactivity, please. There are far, far
    > more linux desktops than there are servers. People expect to have to
    > tune servers (I do, for the servers I maintain). People don't expect
    > to have to tune a desktop to make it run well.

    Oh and even on servers, when your anti-virus proxy reaches a load of 800,
    you're happy no to have too large a time-slice so that you regularly get
    a chance of being allowed to type in commands over SSH.

    Large time-slices are needed only in HPC environments IMHO, where only
    one task runs.


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