lkml.org 
[lkml]   [2004]   [Apr]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: ~500 megs cached yet 2.6.5 goes into swap hell
    Timothy wrote:
    > Linux kernel developers seem to be of the mind that you cannot trust
    > what applications tell you about themselves, so it's better to use
    > heuristics to GUESS how to schedule something, rather than to add YET
    > ANOTHER property to it.

    Both are needed. The thing has to work pretty well, for most people,
    most of the time, without human intervention.

    And there needs to be knobs to optimize performance. Even with no
    conscious end-user administration, a knob on the cron job that runs
    updatedb, setup by the distribution packager, could have wide spread
    impact on the responsiveness of a system, when the user sits down with
    the first cup of coffee to scan the morning headlines and incoming
    email er eh spam.

    As to whether it's two nice calls, or one with dual affect, let's not
    confuse the kernel API with that seen by the user. The kernel should
    provide a minimum spanning set of orthogonal mechanisms, and not be
    second guessing whether the user is out of their ever loving mind to be
    asking for a hot cpu, cold io, job.

    In other words, I wouldn't agree with your take that it's a matter of
    not trusting the application, better to GUESS. Rather I would say that
    there is a preference, and a good one at that, to not use an excessive
    number of knobs as a cop-out to avoid working hard to get the widest
    practical range of cases to behave reasonably, without intervention, and
    a preference to keep what knobs that are there short, sweet and
    minimally interacting.

    --
    I won't rest till it's the best ...
    Programmer, Linux Scalability
    Paul Jackson <pj@sgi.com> 1.650.933.1373
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-03-22 14:02    [W:4.120 / U:0.104 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site