Firefox 7: Telemetry

Based on a blog post originally posted here by Taras Glek, Firefox Developer.

Firefox 7 marks a turning point in how we measure Firefox performance. Traditionally we measured Firefox performance on individual developer machines and our build & release infrastructure. However it turns out synthetic benchmarks do not correspond to real-world Firefox usage: it is difficult to model a “typical” computer in a lab environment. Surprisingly slow consumer hardware, changes in usage patterns, preinstalled bloatware all affect Firefox performance in surprising ways.

Firefox 7 telemetry will prompt users to opt-in to reporting performance data to Mozilla. This data will supplement our existing benchmarking infrastructure to help us optimize future Firefox releases. Telemetry performance metrics are very lightweight and will not negatively impact Firefox performance.

In addition to transmitting data via SSL, Mozilla privacy team worked tirelessly to ensure that no personally-identifiable information is sent via telemetry. Whereas many other software projects stamp this kind of data with a unique per-user id, we opted for a per-session id which is reset every time the browser restarts. Telemetry is also disabled while in private-browsing mode.

The following telemetry data will be gathered in Firefox 7:

Memory usage
CPU core count
Cycle collection times
Startup speed

Use the about:telemetry extension to check on your browser performance. The following screenshot shows how to enable telemetry:

I’m very excited that Firefox finally joins the ranks of cars, airplanes and other software projects in making performance decisions based on real evidence gathered in the wild.

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  1. Stephan Sokolow

    Is there an upper time bound on the use of each session identifier? I know I leave my Firefox open for weeks on end sometimes and I’m not willing to opt into something that would generate a coherent profile of everything I do in that time period.

    (Same reason you can often uniquely identify people with information they’d never think about sharing, like a combination of postal code, birthday, and gender. I KNOW some of the websites I use are hugely niche things and neither Firefox’s “hide everything you’re doing” nor Chrome’s “no access to Firefox extensions” private browsing satisfy my needs)

    September 27th, 2011 at 07:59

  2. Eric Perret

    Is there a way for a website to tap into this performance data, for example using JavaScript?

    September 27th, 2011 at 17:07

  3. Fernando Takai

    Is this data ever going to be available like the crash reports?

    September 27th, 2011 at 19:05

  4. Stephan Sokolow


    By “hide everything you’re doing”, I’m referring to how Firefox’s private browsing requires big messy multi-profile hackery to have a private and a non-private window on-screen at the same time.

    By “no access to Firefox extensions”, I’m just saying that Chrome’s private browsing is lacking in various Firefox-only extensions (stuff Chrome’s crippled API prevents) which I consider essential for comfortable use.

    September 28th, 2011 at 04:12

  5. Joseph Redick

    I have trouble setting my web site up

    October 3rd, 2011 at 20:42

  6. Web Design Phoenix

    Yeah nice attempt, but i expecting that, page loading time if u include this in this report viewable by the user of firefox, it will more useful to seo analyst….

    November 18th, 2011 at 04:30

    1. Web Design New York

      Hi Phoenix
      For tracking the site loading time separate tools are available why you are expecting in firefox

      November 23rd, 2011 at 02:28

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