lkml.org 
[lkml]   [2001]   [Dec]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: Scheduler ( was: Just a second ) ...
    On Dec 18, 2001  13:27 -0500, Doug Ledford wrote:
    > Andreas Dilger wrote:
    > > Yes, esd is an interrupt hog, it seems. When reading this thread, I
    > > checked, and sure enough I was getting 190 interrupts/sec on the
    > > sound card while not playing any sound. I killed esd (which I don't
    > > use anyways), and interrupts went to 0/sec when not playing sound.
    > > Still at 190/sec when using mpg123 on my ymfpci (Yamaha YMF744B DS-1S)
    > > sound card.
    >
    > Weel, evidently esd and artsd both do this (well, I assume esd does now, it
    > didn't do this in the past). Basically, they both transmit silence over the
    > sound chip when nothing else is going on. So even though you don't hear
    > anything, the same sound output DMA is taking place. That avoids things
    > like nasty pops when you start up the sound hardware for a beep and that
    > sort of thing.

    Hmm, I _do_ notice a pop when the sound hardware is first initialized at
    boot time, but not when mpg123 starts/stops (without esd running) so I
    personally don't get any benefit from "the sound of silence". That said,
    asside from the 190 interrupts/sec from esd, it doesn't appear to use any
    measurable CPU time by itself.

    > Context switches per second not playing any sound: 8300 - 8800
    > Context switches per second playing an MP3: 9200 - 9900

    Hmm, something seems very strange there. On an idle system, I get about
    100 context switches/sec, and about 150/sec when playing sound (up to 400/sec
    when moving the mouse between windows). 9000 cswitches/sec is _very_ high.
    This is with a text-only player which has screen output (other than the
    ID3 info from the currently played song).

    Cheers, Andreas
    --
    Andreas Dilger
    http://sourceforge.net/projects/ext2resize/
    http://www-mddsp.enel.ucalgary.ca/People/adilger/

    -
    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 13:14    [W:4.162 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site