lkml.org 
[lkml]   [2004]   [Oct]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: How is user space notified of CPU speed changes?
    From
    Date
    On Sun, 2004-10-24 at 00:17 +0100, Jon Masters wrote:
    > On Sat, 23 Oct 2004 18:42:13 -0400, Lee Revell <rlrevell@joe-job.com> wrote:
    >
    > > Does anyone know how OSX/CoreAudio handles the situation? Apparently
    > > realtime apps work flawlessly on speed scaling laptops under OSX.
    >
    > The difference in implementation between the Intel TSC and PowerPC
    > TB[LU] has been mentioned previously in this thread.

    Well, it was mentioned that there is a difference...

    http://www-106.ibm.com/developerworks/eserver/pdfs/archpub2.pdf

    pg. 39, "Non-constant update frequency".

    "Each time the update frequency changes, the system software is notified
    of the change via an interrupt, or the change was instigated by the
    system software itself. At each such change, the system software must
    compute the current time of day using the old update frequency, compute
    a new value of ticks_per_sec for the new frequency, and save the time of
    day, Time Base value, and the tick rate"

    This was what I wanted to know: does Linux and/or the x86 have a similar
    mechanism? Looks like the answer is no...

    Lee

    -
    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 14:07    [W:0.049 / U:0.008 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site