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!
From: Fred Smith fredex@fcshome.stoneham.ma.us
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?
From which process...? java?
JD
On Tue, Feb 04, 2014 at 02:26:32AM -0800, John Doe wrote:
From: Fred Smith fredex@fcshome.stoneham.ma.us
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?
From which process...? java?
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 fredex@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 ?
HTH, Laurent.
On Tue, Feb 04, 2014 at 02:31:51PM +0000, Laurent Wandrebeck wrote:
Fred Smith fredex@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 wrote:
On Tue, Feb 04, 2014 at 02:31:51PM +0000, Laurent Wandrebeck wrote:
Fred Smith fredex@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.
<snip>
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
<snip>
it appears to be a child of init, since PPID is 1 (the column just to the left of "fredex".)
Suggests that they crashed, or logged out, and this remained running.
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...
<snip>
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.
<snip>
So, I guess this is solved as far as I feel like taking it. Thanks to all (both) of you who offered advice.
One more thing before you drop it - it is, in fact, a firefox thing, and based on the name, either java or perl.... https://bugzilla.mozilla.org/show_bug.cgi?id=860149 (after googling firefox imagedecoder).
mark
From: Fred Smith fredex@fcshome.stoneham.ma.us
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.
Maybe webkit's ImageDecoder "function"...
JD
On Tue, Feb 04, 2014 at 07:43:27AM -0800, John Doe wrote:
From: Fred Smith fredex@fcshome.stoneham.ma.us
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.
Maybe webkit's ImageDecoder "function"...
Firefox uses WebKit????
From: Fred Smith fredex@fcshome.stoneham.ma.us
On Tue, Feb 04, 2014 at 07:43:27AM -0800, John Doe wrote:
Maybe webkit's ImageDecoder "function"...
Firefox uses WebKit????
Ok, maybe I need some vacations... Last try, from the source "mozilla-release/image/src/RasterImage.cpp":
RasterImage::DecodePool::DecodePool() : mThreadPoolMutex("Thread Pool") { if (gMultithreadedDecoding) { mThreadPool = do_CreateInstance(NS_THREADPOOL_CONTRACTID); if (mThreadPool) { mThreadPool->SetName(NS_LITERAL_CSTRING("ImageDecoder")); uint32_t limit; if (gDecodingThreadLimit <= 0) { limit = std::max(PR_GetNumberOfProcessors(), 2) - 1; } else { limit = static_cast<uint32_t>(gDecodingThreadLimit); }
mThreadPool->SetThreadLimit(limit); mThreadPool->SetIdleThreadLimit(limit);
nsCOMPtr<nsIObserverService> obsSvc = mozilla::services::GetObserverService(); if (obsSvc) { obsSvc->AddObserver(this, "xpcom-shutdown-threads", false); } } } }
JD
Fred Smith wrote:
On Tue, Feb 04, 2014 at 02:26:32AM -0800, John Doe wrote:
From: Fred Smith fredex@fcshome.stoneham.ma.us
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?
From which process...? java?
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?
So ImageDecoder is a running process? Then I'd think that locate ImageDecoder would find it, so that you can check.
mark
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