Measures:
1) A while loop is faster than iterating with #each.
2) Check string, variable and block tokens first. They are far more
frequent than interrupt tokens. In their case, checking for an
interrupt can be avoided.
3) String tokens just map to themselves and don't need the special
treatment of BlockBody#render_node (except the resource limit
check).
Benchmark
=========
$ bundle exec rake benchmark:run
Before
------
Run 1)
parse: 41.630 (± 0.0%) i/s - 420.000 in 10.089309s
render: 75.962 (± 3.9%) i/s - 763.000 in 10.066823s
parse & render: 25.497 (± 0.0%) i/s - 256.000 in 10.040862s
Run 2)
parse: 42.130 (± 0.0%) i/s - 424.000 in 10.064738s
render: 77.003 (± 1.3%) i/s - 777.000 in 10.093524s
parse & render: 25.739 (± 0.0%) i/s - 258.000 in 10.024581s
Run 3)
parse: 41.976 (± 2.4%) i/s - 420.000 in 10.021406s
render: 76.184 (± 1.3%) i/s - 763.000 in 10.018104s
parse & render: 25.641 (± 0.0%) i/s - 258.000 in 10.062549s
After
-----
Run 1)
parse: 42.283 (± 0.0%) i/s - 424.000 in 10.028306s
render: 83.158 (± 2.4%) i/s - 832.000 in 10.009201s
parse & render: 26.417 (± 0.0%) i/s - 266.000 in 10.069718s
Run 2)
parse: 41.159 (± 4.9%) i/s - 412.000 in 10.031297s
render: 81.591 (± 3.7%) i/s - 816.000 in 10.018225s
parse & render: 25.924 (± 3.9%) i/s - 260.000 in 10.035653s
Run 3)
parse: 42.418 (± 2.4%) i/s - 424.000 in 10.003100s
render: 84.183 (± 2.4%) i/s - 847.000 in 10.069781s
parse & render: 26.726 (± 0.0%) i/s - 268.000 in 10.029857s
Add a simple profiling system to liquid rendering. Each
liquid tag ({{ }} and {% %}) is processed through this profiling,
keeping track of the partial name (in the case of {% include %}), line
number, and the time it took to render the tag. In the case of {%
include %}, the profiler keeps track of the name of the partial and
properly links back tag rendering to the partial and line number for
easy lookup and dive down. With this, it's now possible to track down
exactly how long each tag takes to render.
These hooks get installed and uninstalled on an as-need basis so by
default there is no impact on the overall liquid execution speed.
Dylan Thacker-Smith