This example was provided by the author of a post on Jekyll Talk in February 2023, entitled 13 seconds build time per page.

A link to a significantly cut-down and redacted version of the original repo was provided in a follow-up. The current profiling results were obtained using a download of that version.

The Gemfile.lock of the repo had pinned the just-the-docs version to v0.3.3, and Jekyll to 4.2.2. A further follow-up reported a build time of 420 seconds for the 559 pages of the cut-down site using just-the-docs v0.3.3, but just 42 seconds with v0.4.0.1

Note that navigation hierarchy of the cut-down repo was broken: parent fields of many source files specify directory names, grand_parent fields are blank, and the hierarchy was 4 levels deep. These issues affected the build times reported in the profiles. They have now been rectified, and all the profiles updated.

The inefficiency of rendering the navigation panel separately for each page of a large site was noted by Joost van der Schee:

The performance of this theme could be fixed by having an autocollapsing menu that gets its active state from javascript. In that case it can be generated once instead of 2000 times (the amount of pages you have).

Pull request #1244 provided an unobtrusive implementation of that suggestion.

  1. v0.4.0 was released only a couple of days before the original post.