Performance Optimizations

[parkr]

Based on #2993.

This actually sped up the build of jekyllrb.com quite a bit already. Such simple fixes! Mostly low-hanging fruit.

[parkr]

/cc @gjtorikian Does this speed up your site's generation time?

[parkr]

Jekyll is complicated:

generated by this graphviz file

[alfredxing]

Yay! Faster builds for everyone! ✨ 🍰

[parkr]

People with large sites will likely be the only ones to really notice a huge difference. But yeah we cut down CPU time in our code a bit. Asking the Liquid team about meeting me halfway: Shopify/liquid#457

[gjtorikian]

Does this speed up your site's generation time?

By about ten seconds, which is pretty nice. It takes about a minute to complete the whole shebang.

I copied your benchmark script in #2993 and it looks like almost 50% of the time is spent by Liquid::Block#render_all. It looks like you're on top of that, too. I'm super interested in following that discussion.

It looks like another sore spot is https://github.com/gjtorikian/jekyll-last-modified-at. It adds about 10 seconds (!) to the build. Not really sure we can do anything about that, though.

[parkr]

@gjtorikian, can you send me the stackprof output and dump file? Feel free to email if it's confidential.