lkml.org 
[lkml]   [2000]   [Mar]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [patch] preemptive kernel, preemptive-2.3.52-A7

    On Wed, 29 Mar 2000 yodaiken@fsmlabs.com wrote:

    > Scene1: without need_resched checks
    > Scene2: with need_resched

    we prefer Scene2 over Scene1 in 99.9% of the time. After all, the guy
    sitting in front of the machine and generating interactive events has
    payed for the hardware so we should preempt ASAP if needed :-)

    if a process is rescheduling frequently (so that it can make the imaginery
    disaster scenario happen in Scene2) should not really happen, because it's
    not an interactive task anymore. A newly woken up thread with the same
    priority does not preempt the currently running thread, plus the currently
    running thread gets a +1 goodness, to model the cache trashing issue you
    raised. Check out preemption_goodness() in sched.c.

    _If_ a thread is so interactive that it's sleeping most of the time and is
    collecting priority through recalculation, then we should schedule to it
    as fast as possible. The frequency of human interactive events is rather
    low. (barring casual mouse movement, which is mostly lightweight)

    Ingo


    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.rutgers.edu
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-03-22 13:57    [W:5.082 / U:0.004 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site