FAQ

As issues and questions crop up, they will be added to this page.

Why is there a single process (tab) restriction?

A trace file contains data on every tab open at the time the trace was captured. Each tab correlates to a renderer process which in Blink contains, besides other things, the main thread, the compositor thread, and any tile rasterizers. When processing the file Big Rig will try to isolate the process to be analyzed, but if it finds there are multiple candidates then it will throw an error. It would be possible to offer a disambiguation dialog, but this would potentially undermine the automated nature of Big Rig.

Big Rig threw a warning about extensions. What gives?

An extension can create a Background Page, which will show up as a separate render process. Big Rig will, as of version 1.0.5, ignore Background Pages when processing trace files. It will, however, warn you that they were present. With the --strict flag enabled Big Rig will throw when it encounters Background Pages.

To work around this you can disable extensions (go to chrome://extensions and disable any active extensions) or run the test in an incognito window. However, do bear in mind that an incognito window affects performance in other ways: Caches, IndexedDB, and LocalStorage (as just three examples) are not written to disk, and, as such, may skew results.