Basic Benchmarks

To make it more fair to pegdown I added ext-gfm-strikethrough and disabled auto-link extension for all parsers that have the option since it causes significant parser slow-down for all parsers:

I also added a flexmark-java configured with all extensions, except for auto-links, for an idea of how extra extensions affect performance.

Latest, Jan 28, 2017 flexmark-java 0.13.1, intellij-markdown from EAP 2017, commonmark-java 0.8.0:

File	commonmark-java	flexmark-java	intellij-markdown	pegdown
README-SLOW	0.420ms	0.812ms	2.027ms	15.483ms
VERSION	0.743ms	1.425ms	4.057ms	42.936ms
commonMarkSpec	31.025ms	44.465ms	600.654ms	575.131ms
markdown_example	8.490ms	10.502ms	223.593ms	983.640ms
spec	4.719ms	6.249ms	35.883ms	307.176ms
table	0.229ms	0.623ms	0.800ms	3.642ms
table-format	1.385ms	2.881ms	4.150ms	23.592ms
wrap	3.804ms	4.589ms	16.609ms	86.383ms

Ratios of above:

File	commonmark-java	flexmark-java	intellij-markdown	pegdown
README-SLOW	1.00	1.93	4.83	36.88
VERSION	1.00	1.92	5.46	57.78
commonMarkSpec	1.00	1.43	19.36	18.54
markdown_example	1.00	1.24	26.34	115.86
spec	1.00	1.32	7.60	65.09
table	1.00	2.72	3.49	15.90
table-format	1.00	2.08	3.00	17.03
wrap	1.00	1.21	4.37	22.71
-----------	---------	---------	---------	---------
overall	1.00	1.41	17.47	40.11

File	commonmark-java	flexmark-java	intellij-markdown	pegdown
README-SLOW	0.52	1.00	2.50	19.07
VERSION	0.52	1.00	2.85	30.12
commonMarkSpec	0.70	1.00	13.51	12.93
markdown_example	0.81	1.00	21.29	93.66
spec	0.76	1.00	5.74	49.15
table	0.37	1.00	1.28	5.85
table-format	0.48	1.00	1.44	8.19
wrap	0.83	1.00	3.62	18.83
-----------	---------	---------	---------	---------
overall	0.71	1.00	12.41	28.48

• VERSION.md is the version log file I use for Markdown Navigator
• commonMarkSpec.md is a 33k line file used in intellij-markdown test suite for performance evaluation.
• spec.txt commonmark spec markdown file in the commonmark-java project
• hang-pegdown.md is a file containing a single line of 17 characters [[[[[[[[[[[[[[[[[ which causes pegdown to go into a hyper-exponential parse time.
• hang-pegdown2.md a file containing a single line of 18 characters [[[[[[[[[[[[[[[[[[ which causes pegdown to go into a hyper-exponential parse time.
• wrap.md is a file I was using to test wrap on typing performance only to discover that it has nothing to do with the wrap on typing code when 0.1 seconds is taken by pegdown to parse the file. In the plugin the parsing may happen more than once: syntax highlighter pass, psi tree building pass, external annotator.
• markdown_example.md a file with 10,000+ lines containing 500kB+ of text.
• table.md is a file with a fairly large table to test table parsing performance