High /usr/bin/X CPU Usage

Pat Kane pekane52 at gmail.com
Wed Sep 7 19:03:52 PDT 2011

It would  be interesting to see strace output of the Xorg process when
it is in that state.    That is a bit tricky to do however, you need to ssh into
the box to run strace, otherwise you might hit a deadlock, see:


Run the strace with detailed timestamps and do not be confused by
"normal" Xorg activity.  You should practice running strace on the
X server when it is not broken.


On Mon, Sep 5, 2011 at 7:46 PM, Robert Massaioli
<robertmassaioli at gmail.com> wrote:
> Hi XOrg Mailing List,
> In a nutshell: I am having issues with /usr/bin/X taking up way too much CPU
> and, when it does start to use more CPU, my entire user experience becomes
> quite laggy. I have tried really hard to solve the problem on my own but I
> was unable to find a solution so I have finally decided that it is time for
> me to ask this mailing list for help. That is the fundamental problem, the
> rest of this post deals with how it happens, what I am running and what I
> have already tried. I could use any help I can get so thank you for reading.
> This link points to a screenshot of htop running showing the constant high
> 40-60% CPU usage that /usr/bin/X now sits at: http://i.imgur.com/mRIzG.png
> My computer is quite powerful and should easily be able to handle any load
> that any part of linux can throw at it. I have a Quad Core i2500k CPU, an
> NVIDIA 560 Ti Graphics Card and 8GB RAM, so no hardware bottlenecks thats
> for sure (and my Windows Partition runs like a breeze; which proves that the
> hardware seems to be solid). However, with that in mind this is what
> happens:
> Start computer, everything is working fine, /usr/bin/X is behaving normally.
> I can play and watch videos with no lag at all.
> Wait some undefined period of time and just work on stuff (I don't actually
> know how to reliably reproduce the problem but it does happen every single
> time I use my linux partition).
> Watch one of my CPU's spike to an average of 50% and keyboard responsiveness
> drop to the point where I can notice the lag in response time. Video
> playback also becomes impossibly slow at this point.
> I would not have thought that the keyboard would be an issue but it is
> lagging so I have a Razer Acosta keyboard if that helps.
> In short, I have no idea what is causing the problem, on the software side I
> am running:
> $ uname -a
> Linux ShhnapDesk 2.6.38-10-generic #46-Ubuntu SMP Tue Jun 28 15:07:17 UTC
> 2011 x86_64 x86_64 x86_64 GNU/Linux
> $ cat /etc/lsb-release
> $ xmonad --version
> xmonad 0.9.2
> My window manager is XMonad as you can see from above and I am also running
> XMobar (0.13) through that. I have tried:
> Asking for help elsewhere:
> http://superuser.com/questions/328612/linux-x11-is-using-up-50-of-one-of-my-cpus-and-lagging-terribly
> Uninstalling Flash because I read that it might be the problem.
> Using Firefox instead of Google Chrome (I found that chrome had some X
> issues in the past)
> Closing every single X program (bar XMonad) to see if /usr/bin/X would start
> behaving again.
> But none of those troubleshooting attempts worked out for me.
> I do not know what else to do other than read through the entire codebase of
> X and try and reverse engineer where my problem lies. If anybody has any
> suggestions then please make them and any extra information that you happen
> to require I will be more than happy to provide. This problem is
> significantly hindering my Linux joy and I love Linux. I use it for
> everything and have done so for the last three years.
> Thanks in advance for any and all help,
> Robert
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