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.

Answer 1

[MathWorks Support Team]

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

 

[Germán]

This bug seemed to be fixed in R2013b, but after upgrading to R2014a it again started using lots of cpu when JxBrowser is enabled... Can this issue be fixed? the HTML help browser is quite bad

[Sebastian]

I also see the bug in R2013b, but agree that it should be fixed.

[Richard Crozier]

I see this bug, or at least the same symptoms in R2014a. Come on Mathworks, you've had two years to fix it now.

[Michal]

Again!!! Same problem on R2014b (linux 64bit).

[Benjamin]

Works for me!

[Alec Jacobson]

I also see this problem in R2014b (mac os x). Switching to HTMLRENDERER did fix the problem (only after restarting MATLAB).

[Tobias]

This answer fixes the CPU load for me on R2015a on Ubuntu 15.04, but the Help browser is nearly unusable with the JxBrowser disabled. The formatting is really scrambled up and links don't work sometimes.

Please fix this problem, the high CPU load regularly drains my battery really fast, which is a huge and annoying problem!

[Anders Glent Buch]

Agree with Tobias on this one! Switching to the HTML renderer is a close to unacceptable solution for me also (running Ubuntu 14.04 x64 with R2015b). I use the docs extensively while coding, and I encourage students to do so also, so this is becoming a real pain. In my situation, the JxBrowser is just incredibly slow, but I also experience the CPU drain. How many releases must we wait before this is fixed?

[Tobias]

I was hoping that this bug concerning high CPU use when idle due to JxBrowser was fixed in R2015b. But unfortunately it still persists!

Dear MathWorks team, can you please comment if this is going to be fixed in the near future (hopefully R2016a)?

Thank you in advance, Tobias

[Darsana Thulasi]

It is best that you contact MathWorks support directly to learn more about this issue.

[Carl Witthoft]

Ummm.. no it has definitely not been fixed. R2015b here, Win7. Pretty sad.

[Sarang Kunte]

Hi Carl, I would suggest contacting MathWorks Techinical support .

[Adam Law]

The bug still exists in R2017a for me.

[Rachel Greenlee]

I have the bug in R2016a

[Kyle Perry]

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/

[Prashant Gupta]

I have the same error in mine 2017b. This is crazy. My CPU throttles to like 340% as soon as I run MATLAB.

[Tim Sonnemann]

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.

[Alex R.]

6 years later, I'm still seeing this in 2019b and 2021b on windows 10 x64 so it doesn't look fixed at all ... the jxbrowser-chromium.exe subprocess of Matlab.exe comes on every time I use the Help and then within minutes it starts keeping 100% cpu usage.

The workaround helped get rid of it, but now the Matlab help hangs when I try to use it (i get blank pages when clicking on sections or in the ToC)

Answer 2

[Anders Glent Buch]

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:

Answer 3

[DGD]

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.

[Walter Roberson]

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.

Answer 4

[timo]

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,

Answer 5

[Helder Oliveira]

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!

[Helder Oliveira]

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');