How To Enable TraceMonkey in Firefox 3.1?

3.1 is pretty fast due to a new JavaScript engine called TraceMonkey being used, however many user would still encounter slowness while using Firefox 3.1, since TraceMonkey is not enabled by default.

In order to start using TraceMonkey you will need to enable it, which once again is not straightforward. Here are some simple steps to enable TraceMonkey in Firefox 3.1.

Step 1: Type about:config in the address bar

Step 2: If this is first time you are editing the configuration, agree to the to be careful dialog box. 

Step 3: In the filter field type: javascript.options.jit.content

Step 4: Change the boolean value from false to true by double clicking on it

Step 5: Restart your Firefox.

That’s it, enjoy a much more faster browsing with your Firefox after you have enabled TraceMonkey. Thanks for the tip Tim.

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Keith Dsouza

I am the editor-in-chief and owner of Techie Buzz. I love coding and have contributed to several open source projects in the past. You can know more about me and my projects by visiting my Personal Website.I am also a social networking enthusiast and can be found active on twitter, you can follow Keith on twitter @keithdsouza. You can click on my name to visit my Google+ profile.

  • Your welcome, and thank you for the link. Much appreciated.


  • joe

    I just downloaded the beta. Seems the default value is now true. So one does not need to do anything anymore, which is a good thing :-)

  • Butai Zhang

    Recently, I tried to build the tracemonkey JavaScript engine in Firefox instead of the whole browser. I compiled tracemonkey-debe29698839\js\src like this:

    Disable JIT:
    make -f Makefile.ref NANOJIT_ARCH=i386 DISABLE_JIT=1
    Enable JIT:
    make -f Makefile.ref NANOJIT_ARCH=i386 ENABLE_JIT=1
    (it’s ENABLE_JIT not DISABLE_JIT in this case, sorry for the mistake before)
    I used V8 and SunSpider benchmarks for tests. But it seemed that there was no difference between JIT ‘on’ and ‘off’ from the results. I guess maybe JIT could not be turned on in the above way. Do you know how to enable it?
    Thank you very much.