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From: Axel Beckert <abe <at> deuxchevaux.org>
Subject: Bug#487927: Fwd: [Liferea-devel] 100% CPU issue(s) revisited [origin: [email protected]]
Newsgroups: gmane.linux.debian.devel.bugs.general
Date: Tuesday 24th March 2009 16:45:27 UTC (over 9 years ago)

When I wrote the following mail, I totally had forgotten where I
initially read that the 100% CPU bug wasn't completely fixed in

So here's the mail I sent just a few hours ago to
[email protected]

----- Forwarded message from Axel Beckert  -----
From: Axel Beckert 
Date: Tue, 24 Mar 2009 13:08:00 +0100
Subject: [Liferea-devel] 100% CPU issue(s) revisited
To: [email protected]


I'm a big fan of Liferea, using it since 1.0.27 from Debian Etch and
with over 700 feeds. (I love the "search all feeds feature", it's my
personal Google News. ;-)

I read in the Liferea blog that the 100% CPU issue is or at least was
a well known problem. Last year in July 1.4.18 was announced and was
said to fix the 100% CPU issue[1]. I also have the feeling that it got
better since then, but for me there is still some random 100% CPU
usage issues left, as also reported in the comments to this

  [1] http://liferea.blogspot.com/2008/07/fix-for-100-cpu-usage-problem.html

1.4.18 is also the version in Debian Lenny, but occasionally I still
have 100% CPU usage. It starts suddenly after hours or sometimes first
after a day of usage or so. My workaround was to restart Liferea until
it happened again. In case it was at 100% CPU usage, the window
closed, then an empty X window of the same size pops up and vanishes
after a few to maybe 15 seconds. Once or twice I had to kill that
ghost window and the liferea-bin process, since it didn't vanish after

I'm involved in the development of Conkeror[2] (don't ask about the
name[3]), a XULRunner based web browser with Emacs look and feel.

With conkeror, we also had a strange more or less random 100% CPU
issue which mostly showed up on Debian, probably since Debian has
disabled JEMALLOC in XULRunner by default.

  [2] http://conkeror.org/, http://packages.debian.org/conkeror
  [3] http://conkeror.org/FAQ#Wheredoesthename.22Conkeror.22comefrom.3F

Using gdb, Nick, one of our developers, found out[4] that this was
caused by the idle timeout for the "frecency" update ([5],
places.frecency.updateIdleTime). Setting this to 0, e.g. via
about:config or startup files, solved the issue.

  [4] http://repo.or.cz/w/conkeror.git?a=commitdiff;h=c92814d3c8b72f70e7a0b3fe1708d7c8c275977b
  [5] http://kb.mozillazine.org/Places.frecency.updateIdleTime

Nick also says that this variable isn't properly initialized if the
XULRunner application doesn't care about it (in comparison to Firefox
et al.). This would explain why it appears at random Conkeror uptimes
(and Liferea uptimes :-), because it could have any, also very small
values on startup which means the 100% CPU usage can start quite early
even when only showing about:blank.

I also added this setting to my productive 1.4.18 Liferea on Debian
Lenny via about:config and haven't had the above described 100% CPU
usage problem anymore since then. Liferea runs smooth for about a
week without any problems.

Haven't used 1.4.26 from Debian Sid that much yet, so I can't say
anything about more recent versions.

Hope this helps someone -- if not even the Liferea developers :-)

		Regards, Axel
[Signature, SF ads and Mailman footer moved to /dev/null]
----- End forwarded message -----

Since it was also a nearly Debian-only issue with Conkeror due to
Debian's XULRunner has JEMALLOC disabled by default, this is probably
also the reason why Liferea has these problems mostly on Debian (and
perhaps also the reason why upstream hasn't noticed them as we did).

		Regards, Axel
Axel Beckert - [email protected], [email protected] - http://noone.org/abe/
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