Google mod_pagespeed

I’ve just downloaded and installed the Debian AMD64 package of the Google Apache Pagespeed module [1].

To see if it worked I used the Google PageSpeed insights tool which gave my blog a rating of 93% (and 88% for mobile) [2].

After installing mod_pagespeed I received the same scores. So it appears that Pagespeed isn’t doing any good according to Google’s analysis! – – [13/Oct/2012:05:22:31 +0000] "GET /wp-content/plugins/openid/f/W.openid.css, HTTP/1.0" 200 2165 "" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1" 0 – – [13/Oct/2012:05:22:31 +0000] "GET /wp-content/themes/atahualpa/js/DD_roundies.js, HTTP/1.0" 200 3679 "" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1" 0 – – [13/Oct/2012:05:22:31 +0000] "GET /wp-includes/js/jquery/jquery.js, HTTP/1.0" 200 33587 "" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1" 0 – – [13/Oct/2012:05:22:33 +0000] "GET /wp-content/themes/atahualpa/images/xlogo.png.pagespeed.ic.ICWmaHBME5.png HTTP/1.0" 200 2267 "" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1" 0

The above sample of web logs shows that the string “pagespeed” is appended to some URLs with a hash of the file contents which apparently allows much longer cache times without making it difficult to change content. So Pagespeed is obviously doing something.

Is Google analysis expected to say that there is no change? Note that my speed scores are 93% and 88% so my site is was apparently quite good before mod_pagespeed was installed – maybe the analysis would report a difference on a site that didn’t perform so well. Now even if mod_pagespeed has given a benefit to real users but not Google tests it still means that I won’t get the SEO benefits that Google apparently gives to fast sites.

Also to make things even more exciting the HTML validator [3] now says that there’s an error in my blog. So not only has mod_pagespeed failed to improve performance in a way that Google notices but it has also broken something!

1 comment to Google mod_pagespeed

  • The error from the validator is odd. It claims a style tag is missing a type attribute. I thought that mod_pagespeed might have optimized it away, which would still make the document valid HTML5 (I believe) but not valid XHTML. It will probably still render correctly for the most times, so fair enough.

    But no. When looking at that line, in the source code, using Chrome, I see a stylesheet include using link rel=’stylesheet’. (Single quotes; mod_pagespeed’s doing?) When asking the validator to show the source on the other hand, I do indeed see the claimed style tag without a type attribute.

    Who’s lying? I then tried wget’ing the page with the validator’s user-agent (W3C_Validator/1.3), my own as well as just some random characters. Sure enough, the validator still gets the inline tag, as well the random characters, while my own user-agent gets the link rel. Perhaps it goes by the assumption that user-agents that are not whitelisted won’t cache the CSS file, and thus benefit from having the CSS inserted inline so they won’t have to open a new http connection on each page load.

    Anyway, Google said this in 2010:

    “While site speed is a new signal, it doesn’t carry as much weight as the relevance of a page. Currently, fewer than 1% of search queries are affected by the site speed signal in our implementation and the signal for site speed only applies for visitors searching in English on at this point.”


    What I’ve heard once — I don’t remember where, or whether it was a rumor or a confirmed statement by Google — is that the speed signal is a very weak signal which is not meant to directly influence the ranking of pages that someone might want to visit. Rather, the rule is enforced in order to quench blackhat “SEO” using compromised or spammed web pages as link farms. In other words, unless your page is terribly slow, you probably don’t have to worry about this signal influencing your Pagerank.