By Jeff Kaufman, Software Engineer, PageSpeed Team
Making your site fast shouldn’t require lots of manual optimization. With mod_pagespeed, an open-source Apache module, you can automatically apply web performance optimization best practices like cache extension, image optimization, and css inlining to speed up your site without a lot of hassle. As of version 0.10.22.4, mod_pagespeed now supports A/B tests integrated with Google Analytics, allowing you to measure how much it speeds up your site on live traffic and experimentally determine the best settings.
We ran an example experiment, comparing mod_pagespeed running with default settings to mod_pagespeed in pass-through mode, on a small blog. This required adding the following lines to our
# half the users get the pagespeed optimizations
# half get an unoptimized site
Average page load time is sensitive to outliers, however, so to better understand the effects it’s helpful to check a histogram:
The clearest change is that mod_pagespeed moved about 7% of page loads from taking 1-3 seconds down to 0-1 second, but there is also an improvement in the long tail.
We encourage you to follow the experiment framework guide and start measuring the effect mod_pagespeed has on your site.
Jeff Kaufman works on mod_pagespeed, an open-source Apache module that helps make the web faster, and is interested in experiment measurement. He also plays for contra dances, organizes other dances, and blogs about dancing, giving, and tech.
Posted by Scott Knaster, Editor