[CentOS] what is: ImageDecoder

Tue Feb 4 14:55:36 UTC 2014
Fred Smith <fredex at fcshome.stoneham.ma.us>

On Tue, Feb 04, 2014 at 02:31:51PM +0000, Laurent Wandrebeck wrote:
> 
> Fred Smith <fredex at fcshome.stoneham.ma.us> a écrit :
> 
> >
> > 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?
> 
> Try pstree ?

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

-- 
---- Fred Smith -- fredex at fcshome.stoneham.ma.us -----------------------------
               But God demonstrates his own love for us in this: 
                         While we were still sinners, 
                              Christ died for us.
------------------------------- Romans 5:8 (niv) ------------------------------