NOTE: The following benchmarks should be viewed within the context of a normal Drupal installation. While fairly accurate, they may include very slight overhead due to the nature of Drupal rendering and PHP autoloading. This may not be the most direct or "raw" comparison of the individual Markdown parsers themselves.
PECL cmark/libcmark (1.0.0/0.28.3) thephpleague/commonmark (0.17.5) erusev/parsedown-extra (1.7.1/0.7.0) michelf/php-markdown (1.8.0)
Bootstrap (README.md)10.79 KB ~0.28ms / ~40.04ms / ~40.36ms ~28.13ms / ~3.25ms / ~31.42ms ~2.30ms / ~2.40ms / ~4.73ms ~5.71ms / ~2.96ms / ~8.75ms
CommonMark(README.md)7.64 KB ~0.17ms / ~1.10ms / ~1.30ms ~12.47ms / ~1.27ms / ~13.78ms ~1.04ms / ~1.10ms / ~2.17ms ~2.70ms / ~1.12ms / ~3.85ms
Homebrew (README.md)8.85 KB ~0.32ms / ~3.68ms / ~4.04ms ~25.99ms / ~2.76ms / ~28.81ms ~1.69ms / ~2.30ms / ~4.03ms ~4.56ms / ~2.37ms / ~6.98ms
jQuery (README.md)15.99 KB ~0.50ms / ~4.04ms / ~4.58ms ~24.99ms / ~3.30ms / ~28.34ms ~3.13ms / ~2.99ms / ~6.17ms ~8.69ms / ~4.18ms / ~12.93ms
Markdown (Original/Syntax)31.69 KB ~0.63ms / ~4.41ms / ~5.08ms ~46.33ms / ~4.86ms / ~51.25ms ~7.78ms / ~6.54ms / ~14.38ms ~12.64ms / ~5.38ms / ~18.08ms
PHP Markdown (README.md)18.23 KB ~0.39ms / ~2.25ms / ~2.67ms ~27.11ms / ~2.32ms / ~29.48ms ~2.70ms / ~2.22ms / ~4.95ms ~7.21ms / ~2.37ms / ~9.62ms
TextMate (README.md)7.29 KB ~0.17ms / ~1.34ms / ~1.54ms ~10.97ms / ~1.51ms / ~12.52ms ~1.17ms / ~1.34ms / ~2.55ms ~2.90ms / ~1.44ms / ~4.37ms
thephpleague/commonmark (README.md)13.08 KB ~0.34ms / ~2.82ms / ~3.19ms ~25.24ms / ~2.57ms / ~27.87ms ~2.01ms / ~2.35ms / ~4.39ms ~5.17ms / ~2.45ms / ~7.66ms
Parsing Averages
PECL cmark/libcmark (1.0.0/0.28.3) thephpleague/commonmark (0.17.5) erusev/parsedown-extra (1.7.1/0.7.0) michelf/php-markdown (1.8.0)
~0.36ms PECL cmark/libcmark (1.0.0/0.28.3) ~75x faster ~8x faster ~17x faster
~26.38ms thephpleague/commonmark (0.17.5) ~75x slower ~10x slower ~5x slower
~2.76ms erusev/parsedown-extra (1.7.1/0.7.0) ~8x slower ~10x faster ~3x faster
~5.81ms michelf/php-markdown (1.8.0) ~17x slower ~5x faster ~3x slower
Rendering Averages
PECL cmark/libcmark (1.0.0/0.28.3) thephpleague/commonmark (0.17.5) erusev/parsedown-extra (1.7.1/0.7.0) michelf/php-markdown (1.8.0)
~3.01ms PECL cmark/libcmark (1.0.0/0.28.3) ~2x slower ~2x slower ~2x slower
~2.92ms thephpleague/commonmark (0.17.5) ~2x faster ~2x slower ~2x slower
~2.65ms erusev/parsedown-extra (1.7.1/0.7.0) ~2x faster ~2x faster ~2x slower
~2.58ms michelf/php-markdown (1.8.0) ~2x faster ~2x faster ~2x faster
Total Averages
PECL cmark/libcmark (1.0.0/0.28.3) thephpleague/commonmark (0.17.5) erusev/parsedown-extra (1.7.1/0.7.0) michelf/php-markdown (1.8.0)
~3.40ms PECL cmark/libcmark (1.0.0/0.28.3) ~9x faster ~2x faster ~3x faster
~29.36ms thephpleague/commonmark (0.17.5) ~9x slower ~6x slower ~4x slower
~5.45ms erusev/parsedown-extra (1.7.1/0.7.0) ~2x slower ~6x faster ~2x faster
~8.48ms michelf/php-markdown (1.8.0) ~3x slower ~4x faster ~2x slower