Monitor consuming loads of CPU

[Gustavo Niemeyer]

landscape-monitor is consuming a lot of CPU in Ubuntu Hardy.

The problem seems to be related to a bug in Twisted's getProcessOutput()
function, which is misbehaving badly in that environment, as may be seen
by executing the attached test case.

[Andreas Hasenack (ahasenack)]

With these packages in hardy, the problem happens:
libglib2.0-0_2.16.1-1ubuntu3_i386.deb
python-gobject_2.14.1-2_i386.deb

Downgrading them to the ones from gutsy fixes it:
python-gobject_2.14.0-0ubuntu1_i386.deb
libglib2.0-0_2.14.1-1ubuntu1_i386.deb

I'm now going to test some releases in between to see if I can pinpoint the exact version where this started happening.

[Andreas Hasenack (ahasenack)]

Issue found:

<seb128> niemeyer: my first guess is that's it's due to this:
<seb128> * Backport signal.set_wakeup_fd from the trunk, requested by desktop team.
<seb128> niemeyer: http://bugzilla.gnome.org/show_bug.cgi?id=481569 is the corresponding pygobject bug
<seb128> and I didn't have the issue on this machine but just upgrade to the current pygobject, which is basically just fixing the -dbg variant
<seb128> and now I get the bug
<seb128> and the only obvious difference is that the new bug was with a python which has this change
<seb128> s/bug/built
<seb128> confirmed
<seb128> building pygobject without using PySignal_SetWakeupFd makes the testcase not eat cpu

[Andreas Hasenack (ahasenack)]

If needed by someone in an emergency (customer, for example), seb128 has provided an updated package which fixes the problem on Hardy:

http://people.ubuntu.com/~seb128/python-gobject_2.14.1-2ubuntu1_i386.deb

It should appear in Hardy very soon now:
<seb128> slangasek: ^ uploaded to hardy, I've just reverted the configure.ac change and ran autoconf to update the configure
<slangasek> seb128: ok, cheers

[Andreas Hasenack (ahasenack)]

This has been fixed and released for Hardy:

2.14.1-2ubuntu1
Published in hardy-release 4 hours ago

pygobject (2.14.1-2ubuntu1) hardy; urgency=low

  * debian/patches/61_dont_use_setwakeupfd.patch:
    - don't use SetWakeupFd, it creates abnormal cpu usage in some situations

 -- Sebastien Bacher < <email address hidden>> Wed, 19 Mar 2008 22:17:53 +0100

[Andreas Hasenack (ahasenack)]

This happened again in intrepid and is being tracked at bug #250876