Firefox Tracking Protection

So here’s something new I learned today… Firefox has a tracking protection mode.

For those not aware, many (most?) websites include tracking Javascript which provides third parties and the website owner with information about you. It’s not all evil but it does invade your privacy.
Tracking Protection for Firefox at Web 2.0 Security and Privacy 2015
With tracking protection enabled Firefox will block known trackers and has the nice side effect of providing a major browsing speed up.

For a while I’ve configured Firefox to disable third-party cookies. I think it’s time to add enabling tracking protection to my list of new installation steps.

It’s important for the web that no single browser ever gets to the dominance that IE once had. Firefox dethroned IE but now Chrome is becoming dominant. It’s doubtful Chrome would ever implement privacy protecting feature like this – it hurts Google’s primary advertising business too much. If you care about the web and your privacy, consider using Firefox. A healthy number of Firefox users keeps the rest of the web browsers honest.

Linux x86_64 and Javascript

The competition between browsers in the area of Javascript performance has led to some pretty dramatic performance increases in the last couple of years. A lot of this has been accomplished through Javascript just in time (JIT) compilers. What JITs do is convert the Javascript into native instructions which execute a lot faster than more abstract forms. The one downside to this approach is that each native architecture must be supported to get the speed boost.

If you follow Javascript performance you know that recent versions of Firefox have a JIT. What you may not know is that there is no JIT in Firefox for x86_64. This isn’t that big of a problem for Windows since there are so few 64-bit windows users but Linux distributions have been native 64-bit for quite some time. So if you’ve installed a 64-bit version of your faviourite Linux distribution you are getting far slower Javascript performance in Firefox than if you had installed the i686 version. How much slower?

The following benchmarks were executed on an i7-930 running Fedora 12, Firefox 3.5.8 and Epiphany 2.28.2. The benchmarks I used are the SunSpider and V8 Javascript benchmarks.

Browser/arch V8 (higher is better) SunSpider (lower is better)
Firefox i686 PAE 402 1002.6ms
Firefox x86_64 277 2131.2ms
Epiphany x86_64 887 1261.0ms

These results show that the Javascript performance of i686 Firefox is a lot better than x86_64. The Epiphany web browser is based on Webkit which, based on these results, I’m guessing does have a x86_64 JIT.