Browser Extension system requirements and performance optimization information

System Requirements/Resource Utilization

PixieBrix resources depend on the number of mods activated, the number of frames where those mods are running, and the size of those mods.

The following are estimates for normal PixieBrix usage:

  • Hard Drive Storage:

    • Browser Extension (Unzipped): 36.4 MB. Note that Chrome has a long-standing bug where older extension versions are retained on disk after updates. If hard-drive space is limited, you may need to run a recurring job to clean old versions of the extension.

    • Package Definitions: 5-25 MB. Package storage space depends on how many mods the user has access to and the size of those mods (e.g. if the mod includes embedded images directly in the package definition.)

  • Memory

    • Baseline: 34 MB

    • Peak: 130 MB. Note that Chrome runs memory garbage collection automatically based on available system memory.

Measuring Resource Utilization/Performance

Basic: Chrome Task Manager

Open the Chrome Task Manager, by clicking Chrome's 3 dot menu and selecting More Tools > Task Manager.

Locate the entry for Extension: PixieBrix.

If the Memory Footprint column is not visible, right-click on the header row and select "Memory Footprint" to show that column.

Advanced: Use Chrome Lighthouse to Measure Impact on Page Load

Lighthouse is a tool in Google Chrome to measure page performance and quality. To measure the impact of browser extension on page load, you can:

  • Run a Lighthouse performance report without the extension active

  • Run a Lighthouse performance report with the extension active

For each, Lighthouse will generate a report with an overall score as well as other key performance metrics, e.g.: First Contentful Paint and Total Blocking Time.

Tuning Memory Utilization

Chromium Memory Saver

Modern Chromium browsers (e.g., Chrome and Edge) include a Memory Saver mode that automatically frees memory on inactive tabs until they are revisited. The browser will also free up PixieBrix's memory from those inactive tabs.

Verify your Memory Saver settings: chrome://settings/performance

Restricting PixieBrix Frame Origins

By default, PixieBrix includes a small bootstrap content script on each frame. PixieBrix then dynamically imports content required to run mods as necessary.

To limit memory utilization, you can set an IT policy restricting PixieBrix to only run on the necessary origins. See Browser Extension Security for instructions

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