What Is: ImageDecoder

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I’m suddenly noticing multiple threads named “ImageDecoder” showing up in the output of top (when threads are turned on with “H”).

I’ve no clue what this is, and haven’t found out much about it by searching.

Can someone tell me what it is, and if it’s doing anything useful or just wasting cycles?

thanks!

9 thoughts on - What Is: ImageDecoder

  • Um, it appears in the process list as “ImageDecoder”. I don’t know how one would determine that it’s java or not.

    Can you give me a hint?

  • Fred Smith wrote:
    about it by useful or

    So ImageDecoder is a running process? Then I’d think that locate ImageDecoder would find it, so that you can check.

    mark

  • pstree shows nothing by that name.

    here’s some output from top (with ppid and thread id added):

    23040 fredex 20 0 2424m 1.2g 41m S 0.3 16.3 1:13.71 1 fredex ImageDecoder #1
    23123 fredex 20 0 2424m 1.2g 41m S 0.3 16.3 1:12.82 1 fredex ImageDecoder #2
    23189 fredex 20 0 2424m 1.2g 41m S 0.3 16.3 1:13.47 1 fredex ImageDecoder #3
    23190 fredex 20 0 2424m 1.2g 41m S 0.3 16.3 1:12.73 1 fredex ImageDecoder #4
    23191 fredex 20 0 2424m 1.2g 41m S 0.3 16.3 1:14.02 1 fredex ImageDecoder #5

    it appears to be a child of init, since PPID is 1 (the column just to the left of
    “fredex”.)

    given that “ImageDecoder #1” is process 23040, doing “ps -eLf | grep 23040” reveals:

    fredex 23011 1 23040 0 40 Feb03 ? 00:01:13 /home/fredex/myfiles/programs/firefox-19/firefox/firefox

    It appears to be some kind of firefox alias, though I don’t understand that relationship…

    further:

    $ ps -eLf | grep firefox fredex 1152 1001 1152 0 1 09:47 pts/3 00:00:00 grep firefox fredex 23011 1 23011 7 40 Feb03 ? 00:59:47 /home/fredex/myfiles/programs/firefox-19/firefox/firefox fredex 23011 1 23014 0 40 Feb03 ? 00:00:10 /home/fredex/myfiles/programs/firefox-19/firefox/firefox fredex 23011 1 23015 0 40 Feb03 ? 00:00:34 /home/fredex/myfiles/programs/firefox-19/firefox/firefox fredex 23011 1 23016 0 40 Feb03 ? 00:03:06 /home/fredex/myfiles/programs/firefox-19/firefox/firefox fredex 23011 1 23017 0 40 Feb03 ? 00:00:00 /home/fredex/myfiles/programs/firefox-19/firefox/firefox fredex 23011 1 23018 0 40 Feb03 ? 00:00:00 /home/fredex/myfiles/programs/firefox-19/firefox/firefox fredex 23011 1 23019 0 40 Feb03 ? 00:00:01 /home/fredex/myfiles/programs/firefox-19/firefox/firefox fredex 23011 1 23020 0 40 Feb03 ? 00:00:01 /home/fredex/myfiles/programs/firefox-19/firefox/firefox fredex 23011 1 23021 0 40 Feb03 ? 00:00:01 /home/fredex/myfiles/programs/firefox-19/firefox/firefox fredex 23011 1 23022 0 40 Feb03 ? 00:00:01 /home/fredex/myfiles/programs/firefox-19/firefox/firefox fredex 23011 1 23023 0 40 Feb03 ? 00:00:01 /home/fredex/myfiles/programs/firefox-19/firefox/firefox fredex 23011 1 23024 0 40 Feb03 ? 00:00:01 /home/fredex/myfiles/programs/firefox-19/firefox/firefox fredex 23011 1 23025 0 40 Feb03 ? 00:00:23 /home/fredex/myfiles/programs/firefox-19/firefox/firefox fredex 23011 1 23027 0 40 Feb03 ? 00:00:00 /home/fredex/myfiles/programs/firefox-19/firefox/firefox fredex 23011 1 23028 0 40 Feb03 ? 00:00:00 /home/fredex/myfiles/programs/firefox-19/firefox/firefox fredex 23011 1 23029 0 40 Feb03 ? 00:00:00 /home/fredex/myfiles/programs/firefox-19/firefox/firefox fredex 23011 1 23030 0 40 Feb03 ? 00:00:00 /home/fredex/myfiles/programs/firefox-19/firefox/firefox fredex 23011 1 23033 0 40 Feb03 ? 00:00:23 /home/fredex/myfiles/programs/firefox-19/firefox/firefox fredex 23011 1 23035 0 40 Feb03 ? 00:00:00 /home/fredex/myfiles/programs/firefox-19/firefox/firefox fredex 23011 1 23036 0 40 Feb03 ? 00:00:00 /home/fredex/myfiles/programs/firefox-19/firefox/firefox fredex 23011 1 23040 0 40 Feb03 ? 00:01:14 /home/fredex/myfiles/programs/firefox-19/firefox/firefox fredex 23011 1 23054 0 40 Feb03 ? 00:00:00 /home/fredex/myfiles/programs/firefox-19/firefox/firefox

    where the 2nd column is the PID, the 3rd is the PPID and the 4th is
    “LWP”, which I take to also be the same as “thread ID.”

    so, Firefox has spawned a ton of child threads, and some of them appear in top as “Image Decoder #x”. I dunno WHY they have a strange name, but at least I now know where they came from.

    I find it somewhat odd that I’ve never seen them before (I just upgraded to a new motherboard and 6-core CPU, from previously having had a 2-core CPU) and suddenly I see them in top. I’ve spent a fair amount of time, over the years, staring at top output, but don’t recall ever seeing those there before.

    And yes, it’s the same CentOS installation, I just put a new MB into the system and fired it up.

    So, I guess this is solved as far as I feel like taking it. Thanks to all
    (both) of you who offered advice.

    Fred

  • From: Fred Smith

    Ok, maybe I need some vacations… Last try, from the source “mozilla-release/image/src/RasterImage.cpp”:

    RasterImage::DecodePool::DecodePool()