Build time

Website build profiles

  1. Just the Docs
  2. Just the Docs Tests
  3. endoflife.date
  4. machinetranslate.org

For small sites, the build time should be only a few seconds. For larger sites, it can be annoyingly long: several minutes or more. This may be partly due to inefficiency of Jekyll 3,1 or of the Liquid code that builds the navigation panel when using Just the Docs.

Using Jekyll 4 locally to test a site may give (slightly) different results from the default Jekyll 3 build on GitHub, but it is significantly faster.

However, the HTML of a typical Just the Docs site with hundreds of pages in the navigation seems to be necessarily large: the expanders on all parent pages support access to all child pages, so the navigation has to include a link to every included page! And different pages show different links as active, so the entire navigation panel can’t simply be cached, in general.

The command bundle exec jekyll clean; bundle exec jekyll build --profile cleans the caches and builds the website, then outputs a table showing the CPU time spent in the various files, together with the total build time.

The following tables are extracts from profiles produced by building websites using clones of public repositories, using theme or remote_themme to specify different versions of Just the Docs: v0.3.3, v0.4.0.rc1, v0.4.0.rc2, and v0.4.0.rc3.

The main interest is the time spent in the _includes/nav.html, which generally dominates the time in all the other files. (The file _layouts/default.html includes nav.html, so its time is always higher.)

The navigation code was the same in v0.3.3 and v0.4.0.rc1. The navigation code in v0.4.0.rc2 turned out to be more efficient for one large site (reducing build time from 48 seconds to 9 seconds) but an order of magnitude slower for another large site (increasing build time from 313 seconds to 2975 seconds). The latest version v0.4.0.rc3 maintains the efficient build of the former site, and reduces the build time of the latter site to 391 seconds.1

The profiling was done a MacBook Air (M2, 2022) running macOS Monterey (12.5).

Just the Docs

The repository for this website is at https://github.com/just-the-docs/just-the-docs.

The website at https://just-the-docs.github.io/just-the-docs/:

  • has 22 pages
  • has a shallow navigation hierarchy, with only one level 3 page
  • has 15 nav_order values, all integers
  • has 5 child pages with no
  • has a 404 page with a numerical title value
  • is built using Jekyll v3.8.7

The Just the Docs theme website is quite small (? pages), with a modest navigation hierarchy, not using collections. The pages generally have numerical nav_order values, except for the child pages of Utilities, which are implicitly ordered by their title strings. The 404 page has a numerical title, but is excluded from the navigation.

v0.3.3 done in 1.991 seconds

Profile
Filename Count Bytes Time
_layouts/default.html 22 504.19K 0.406
_includes/nav.html 22 74.65K 0.229
_layouts/vendor/compress.html 22 439.00K 0.143
_includes/vendor/anchor_headings.html 22 253.50K 0.054
_includes/head.html 22 42.78K 0.054
assets/js/zzzz-search-data.json 1 97.09K 0.041

v0.4.0.rc1 done in 1.938 seconds

Profile
Filename Count Bytes Time
_layouts/default.html 22 504.19K 0.400
_includes/nav.html 22 74.65K 0.226
_layouts/vendor/compress.html 22 439.00K 0.142
_includes/vendor/anchor_headings.html 22 253.50K 0.054
_includes/head.html 22 42.78K 0.053
assets/js/zzzz-search-data.json 1 97.09K 0.040

v0.4.0.rc2 done in 1.995 seconds

Profile
Filename Count Bytes Time
_layouts/default.html 22 504.19K 0.415
_includes/nav.html 22 74.65K 0.233
_layouts/vendor/compress.html 22 439.00K 0.146
_includes/vendor/anchor_headings.html 22 253.50K 0.057
_includes/head.html 22 42.78K 0.054
assets/js/zzzz-search-data.json 1 97.09K 0.041

v0.4.0.rc3 done in 1.945 seconds

Profile
Filename Count Bytes Time
_layouts/default.html 22 504.19K 0.404
_includes/nav.html 22 74.65K 0.233
_layouts/vendor/compress.html 22 439.00K 0.149
_includes/vendor/anchor_headings.html 22 253.50K 0.057
_includes/head.html 22 42.78K 0.049
assets/js/zzzz-search-data.json 1 97.09K 0.040

Just the Docs Tests

The repository for this website is at https://github.com/just-the-docs/just-the-docs-tests.

The website at https://just-the-docs.github.io/just-the-docs-tests/:

  • has 110 pages
  • has a rich 3-level navigation hierarchy with 43 level 3 pages and 9 collections
  • has test pages with numerical, string, and no nav_order values
  • has an excluded 404 page with a numerical title
  • was built using Jekyll v3.8.7

v0.3.3 done in 16.85 seconds

Profile
Filename Count Bytes Time
_layouts/default.html 110 3266.93K 14.218
jekyll-remote-theme-20221010-86351-cvopry/_includes/nav.html 110 2183.14K 13.257
jekyll-remote-theme-20221010-86351-cvopry/_includes/head.html 110 190.86K 0.540
_layouts/vendor/compress.html 110 2858.39K 0.209
jekyll-remote-theme-20221010-86351-cvopry/_includes/vendor/anchor_headings.html 110 191.49K 0.129
assets/js/zzzz-search-data.json 1 86.96K 0.091

v0.4.0.rc1 done in 17.689 seconds

Profile
Filename Count Bytes Time
_layouts/default.html 110 3193.41K 14.258
jekyll-remote-theme-20221010-86581-1bvzujk/_includes/nav.html 110 1859.26K 12.847
jekyll-remote-theme-20221010-86581-1bvzujk/_includes/head.html 110 201.60K 0.553
_layouts/vendor/compress.html 110 2711.24K 0.213
jekyll-remote-theme-20221010-86581-1bvzujk/_includes/vendor/anchor_headings.html 110 191.49K 0.128
assets/js/zzzz-search-data.json 1 82.27K 0.061

v0.4.0.rc2 done in 22.095 seconds

Profile
Filename Count Bytes Time
_layouts/default.html 110 3374.24K 18.984
jekyll-remote-theme-20221010-86786-7mh81d/_includes/nav.html 110 2032.36K 17.646
jekyll-remote-theme-20221010-86786-7mh81d/_includes/head.html 110 201.60K 0.538
_layouts/vendor/compress.html 110 2828.05K 0.219
jekyll-remote-theme-20221010-86786-7mh81d/_includes/vendor/anchor_headings.html 110 191.49K 0.130
assets/js/zzzz-search-data.json 1 82.27K 0.051

v0.4.0.rc3 done in 8.414 seconds

Profile
Filename Count Bytes Time
_layouts/default.html 110 3368.20K 5.229
jekyll-remote-theme-20221010-86921-slj0jj/_includes/nav.html 110 2032.64K 3.859
jekyll-remote-theme-20221010-86921-slj0jj/_includes/head.html 110 196.66K 0.547
_layouts/vendor/compress.html 110 2821.46K 0.217
jekyll-remote-theme-20221010-86921-slj0jj/_includes/vendor/anchor_headings.html 110 191.49K 0.126
assets/js/zzzz-search-data.json 1 82.27K 0.065

endoflife.date

The repository for this website is at https://github.com/endoflife-date/endoflife.date.

The website at https://endoflife.date:

  • has 139 pages
  • has a flat navigation hierarchy: all pages are top-level
  • has no nav_order values: all pages are ordered by their title strings
  • has no 404 page
  • was built using Jekyll v4.2.2

In practice, the website reduces the build time to about 7 seconds using a simplified version of _includes/nav.html. For profiling, that file was removed.

v0.3.3 TOTAL TIME: 48.6643

Profile
Filename Count Bytes Time
just-the-docs-0.3.3/_layouts/default.html 139 4544.87K 46.608
just-the-docs-0.3.3/_includes/nav.html 139 2017.90K 44.714
just-the-docs-0.3.3/_includes/head.html 139 690.52K 1.811
_includes/head_custom.html 139 488.13K 0.443
_layouts/product.html 136 1107.56K 0.430
sitemap.xml 1 42.39K 0.263
assets/js/zzzz-search-data.json 1 168.11K 0.061

v0.4.0.rc1 TOTAL TIME: 48.6768

Profile
Filename Count Bytes Time
just-the-docs-0.4.0.rc1/_layouts/default.html 139 4217.32K 46.887
just-the-docs-0.4.0.rc1/_includes/nav.html 139 1611.63K 44.404
just-the-docs-0.4.0.rc1/_includes/head.html 139 691.33K 1.805
_includes/head_custom.html 139 488.13K 0.433
_layouts/product.html 136 1107.56K 0.424
sitemap.xml 1 42.39K 0.264
assets/js/zzzz-search-data.json 1 163.30K 0.052

v0.4.0.rc2 TOTAL TIME: 9.0386

Profile
Filename Count Bytes Time
just-the-docs-0.4.0.rc2/_layouts/default.html 139 4227.09K 7.196
just-the-docs-0.4.0.rc2/_includes/nav.html 139 1611.63K 4.756
just-the-docs-0.4.0.rc2/_includes/head.html 139 691.33K 1.731
_layouts/product.html 136 1107.56K 0.477
_includes/head_custom.html 139 488.13K 0.455
sitemap.xml 1 42.39K 0.267
assets/js/zzzz-search-data.json 1 163.30K 0.063

v0.4.0.rc3 TOTAL TIME: 8.8050

Profile
Filename Count Bytes Time
just-the-docs-0.4.0.rc3/_layouts/default.html 139 4218.81K 7.018
just-the-docs-0.4.0.rc3/_includes/nav.html 139 1611.63K 4.625
just-the-docs-0.4.0.rc3/_includes/head.html 139 685.09K 1.718
_includes/head_custom.html 139 488.13K 0.438
_layouts/product.html 136 1107.56K 0.428
sitemap.xml 1 42.39K 0.265
assets/js/zzzz-search-data.json 1 163.30K 0.054

machinetranslate.org

The repository for this website is at https://github.com/machinetranslate/machinetranslate.org

The website at https://machinetranslate.org:

  • has 350 pages, built from 357 source files with titles
  • has a rich 3-level navigation hierarchy, with 51 level 3 pages
  • has 236 nav_order values (234 integers, 2 blank)
  • has an excluded 404 page with a string title value
  • was built using Jekyll v3.9.2

The file engines/youdao.md was edited to comment out non-Latin characters in URLs.

v0.3.3 done in 286.939 seconds

Profile
Filename Count Bytes Time
_layouts/default.html 350 19934.53K 260.383
jekyll-remote-theme-20221010-99410-f0d2i0/_includes/nav.html 350 14237.38K 226.985
_includes/head.html 350 762.21K 1.497
assets/js/zzzz-search-data.json 1 742.95K 1.023

v0.4.0.rc1 done in 313.314 seconds

Profile
Filename Count Bytes Time
_layouts/default.html 350 17117.10K 288.068
jekyll-remote-theme-20221010-367-hpbs4l/_includes/nav.html 350 11241.54K 242.392
_includes/head.html 350 762.21K 1.429
_layouts/vendor/compress.html 350 15610.93K 0.943
assets/js/zzzz-search-data.json 1 715.56K 0.864

v0.4.0.rc2 done in 2975.7 seconds (!)

Profile
Filename Count Bytes Time
_layouts/default.html 350 17606.56K 2949.965
jekyll-remote-theme-20221010-1546-1e05xea/_includes/nav.html 350 11706.39K 2909.030
_includes/head.html 350 762.21K 1.430
_layouts/vendor/compress.html 350 15939.06K 0.961
assets/js/zzzz-search-data.json 1 715.56K 0.892

v0.4.0.rc3 done in 391.152 seconds

Profile
Filename Count Bytes Time
_layouts/default.html 350 17601.79K 364.902
jekyll-remote-theme-20221010-967-6k2xcb/_includes/nav.html 350 11706.72K 318.016
_includes/head.html 350 762.21K 1.502
_layouts/vendor/compress.html 350 15933.24K 0.993
assets/js/zzzz-search-data.json 1 715.56K 0.907

  1. Just the Docs does not yet support use of Jekyll 4. ↩ ↩2