lkml.org 
[lkml]   [2004]   [Jan]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [PATCH] 2.6.0 batch scheduling, HT aware
    From
    Date
    On Fri, 02 Jan 2004 12:56:16 PST, Davide Libenzi said:
    > On Fri, 2 Jan 2004, Bill Davidsen wrote:
    >
    > > Yes and even worse, if you stop running setiathome the scientific task
    > > *still* only gets half the available CPU!
    >
    > Look that this is not true. If one core is not running any task, the idle
    > task (if not polling) does "hlt" and the "what they call Fetch And

    What Bill said was:

    >> memory-bound seti&home at CPU1. Even without hyperthreading, your
    >> scientific task is going to run at 50% of speed and seti&home is going
    >> to get second half. Oops.

    > Yes and even worse, if you stop running setiathome the scientific task
    > *still* only gets half the available CPU!

    So Bill is pointing out that on a *normal* SMP, you get 50% whether or
    not the other processor is busy.

    > The difference is that with HT running a task on one sibling actually
    > does (or can) slow the other. That's not true with true SMP, at least
    > not directly, since the resourses shared (memory and disk) are much
    > farther away from the CPU.

    And this is where Bill talks about issues like the one you mentioned about
    sharing the dispatch engine.

    So I think you and Bill are actually saying the same exact thing.

    [unhandled content-type:application/pgp-signature]
    \
     
     \ /
      Last update: 2005-03-22 13:59    [W:0.022 / U:0.220 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site