MATLAB Answers

2

Why does MATLAB cause my CPU to spike even when MATLAB is idle in MATLAB 8.0 (R2012b)?

Using the Linux "top" command, I can see that MATLAB is using a great deal of the CPU, even when MATLAB is idle, i.e. not running any programs.
After some time (sometimes 45 minutes, sometimes a couple of hours) of opening a session of MATLAB, MATLAB's CPU usage will spike for a few seconds (2-5 seconds) and then drop for a few seconds. This will continue to happen until MATLAB is closed.

Products


Release

R2014b

5 Answers

Answer by MathWorks Support Team on 10 Mar 2016
 Accepted Answer

This is a bug in MATLAB 8.0 (R2012b) and later releases. This issue may appear in MATLAB R2012a as well. This issue may be related to the new Help browser.
Beginning in MATLAB R2012b, the Help Browser uses a different renderer called the JxBrowser, which provides an enhanced help browsing experience. Because this may be an issue with the JxBrowser, try disabling the JxBrowser and instead use the HTML renderer (which may provide a slightly degraded Help Browser experience).
Launch a new session of MATLAB, and try to disable JxBrowser completely during this session, which can be done by executing the following command at the beginning of a MATLAB session:
 
com.mathworks.mlwidgets.html.HtmlComponentFactory.setDefaultType('HTMLRENDERER');
This will set a preference disabling JxBrowser, which can be undone with the command:
 
com.mathworks.mlwidgets.html.HtmlComponentFactory.setDefaultType([]);
NOTE: This bug has been fixed in MATLAB R2015a and later versions. Here is a link to its external bug report:
https://www.mathworks.com/support/bugreports/914291
 

  17 Comments

Hello Adam and Rachel,
If you are seeing this issue past R2015a, please contact us so we can provide support.
www.mathworks.com/support/contact_us/
I have the same error in mine 2017b. This is crazy. My CPU throttles to like 340% as soon as I run MATLAB.
The fix (switching to HTML renderer) works for me (Matlab R2015a, Ubuntu 16.04) as it removes the incredible CPU load of the JxBrowser.
To make the HTML renderer's text visible/legible, you need to check an option:
Home -> Preferences -> Fonts: check " use antialiasing to smooth desktop fonts (requires MATLAB restart)"
That does it for me, all is well again.

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Answer by Anders Glent Buch on 26 Oct 2015
Edited by Anders Glent Buch on 26 Oct 2015

Just in the hope of keeping this topic alive - the problem persists on Ubuntu 15.04 x64 using latest and greatest version of MATLAB (R2015b). Using JxBrowser causes frequent CPU spikes (100 % usage of one of my 4 cores), wheres HTML renderer does not.
However, this time all text in the HTML rendered help is scrambled. Have a look:
I noticed similar artifacts in the doc search input in the top right corner when resizing the main MATLAB window:

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Answer by DGD
on 12 Dec 2015
Edited by DGD
on 12 Dec 2015

If you only need to use the Help occasionally, you can start a second instance of Matlab, keep it on the side, use the Help there, and when you don't need it, just quit that instance of Matlab. It's a silly solution, but it's better than the annoying cpu load or useless scrambled HTML renderer.
If you need the Help to be available all the time, well, then you need help.

  1 Comment

On my OS-X system, the help browser takes a fair bit of time to come up, enough so that I usually start thinking it is not going to come up, as if I had used the wrong commands. It is long enough that if I bring it up then I am going to want to leave it up to avoid waiting that long when I need it.
I use the documentation quite a bit. I do not happen to use the help browser much, though, as I usually google search instead. I like to be sure that I get the details right when I answer questions.

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Answer by timo
on 22 Jul 2018

I observe a lot of lag in Live editor and i see i have like 5 JxChromium Native process opened. I dont understand why Live Editor with Symbolic calculations makes it so laggy,

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Answer by Helder Oliveira on 17 Oct 2018

What is the default parameter of this command?
I'm using MATLAB 2018a in Kubuntu 18.04.
Using the HTMLRENDERER the images are not loaded into the doc. I try to revert using the command using the [] but I causes a strange behavior I open the docs but when I close it the matlab window is froze!

  1 Comment

Actually I figured it out! I tried to put 'JxBrowser' as parameter and Ive got the error below which says the only two possibilities.
Back to the HTMLPANEL solved my problem.
>> com.mathworks.mlwidgets.html.HtmlComponentFactory.setDefaultType('JxBrowser');
Invalid type. Please enter one of:
HTMLPANEL - uses JxBrowser for HTML rendering
HTMLRENDERER - uses HTMLRenderer, using ICE browser for HTML rendering
>> com.mathworks.mlwidgets.html.HtmlComponentFactory.setDefaultType('HTMLPANEL');

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