Because .com Wasn't Available

This post originally appeared on the Perf Planet Performance Calendar on December 7th, 2013. Domain sharding has long been considered a best practice for pages with lots of images.  The number of domains that you should shard across depends on how many HTTP requests the page makes, how many connections the client makes to each domain, and the available bandwidth.  Since it can be challenging to change this dynamically (and can cause browser caching issues), people typically settle on a fixed number of shards - usually two.   An article published earlier this year by Chromium contributor William Chan outlined the risks of sharding across too many domains, and Etsy was called out as an example of a site that was doing this wrong.  To quote the article: “Etsy’s sharding causes so much congestion related spurious retransmissions that it _dramatically_ impacts page load time.”  At Etsy we're pretty open with our performance work, and we’re always happy t...

This is a follow-up to my " 1,000,000 Push-ups " post.  Check that out for the reasoning behind this challenge. November 19th was my birthday, and it also marked the end of the second year of my push-up challenge.  For the last year my goal was to average 100 push-ups per day, and I finished five push-ups ahead of that goal, with a running total of 54,805 push-ups.  This isn't a magical coincidence, there's a strong rubber banding effect with my color coded spreadsheet .  When I get behind, I do more push-ups to catch up.  When I get ahead, I know that I can take a day off if I get tired or lazy.  This kept me hovering right around my target throughout the year.   If you look at the " Year 2 " tab in the doc, you will see that there was a lot more yellow than in year one.  This is largely because I got sick at the end of April, and had two consecutive days with zero push-ups.  It took me quite a while to catch back up, because I didn't hav...

** Update 12/03/13 ** - This article was deleted by Wikipedia moderators.  If you want the full background on why, check out the deletion talk page .  I have just moved the article to the Web Platform Wiki , which is a more appropriate place for it. After my last post with its abundance of footnotes, some people asked for a place on the web where they can see an aggregated list of performance resources.  This has been tried in the past , and I believe that it has failed because it has always relied on a single person or entity to update the list.  Ideally we would like to have something that fulfills the following goals: Hosted by a non-partial third party Anyone can update - no single point of failure An existing site that people trust, so we don't have to reinvent the wheel A site with a bright future - we don't want this to be obsolete in a few months This is starting to sound vaguely familiar... That's right, the new home (hopefully) for Web Perf...

When you work on web performance every day, it is easy to assume that the best practices are widely known, widely understood, and widely followed.  Unfortunately, as I have learned through a couple of different experiences recently, this is not the case.  It is frankly astounding how many websites are still failing to implement the best practices that Steve Souders outlined in his book " High Performance Websites " over six years ago .  Six years is an eternity when it comes to web development, but I still regularly meet professional software engineers who are surprised when they hear about the rules that the WPO community evangelizes on a daily basis. First, The Data Let's try to scope the problem.  Using data from the HTTP Archive , we know that: Average PageSpeed score is still in the 70's Pages talk to 17 domains on average Only 44% of resources have proper caching headers 23% of resources are still uncompressed Via Radware we know that pages ar...

For context about 30 day challenges, watch  this Ted Talk  by  Matt Cutts . My 30 day challenge in September was to be a vegetarian - and a true vegetarian, so no meat whatsoever, including seafood.  I've thought about doing this challenge for a while, and  this video pushed me over the edge.  My goals for this challenge were simple: See what it's like to live as a vegetarian, and what options are available Be more conscious about meat consumption in general See if this is something that I could sustain long-term I did pretty well throughout the month, and only slipped once.  During the first week of the challenge I was at my great-aunt's 100th birthday party, and it was at a restaurant with a fixed menu.  The only options were chicken, salmon, or steak.  The kitchen said that they could make me a plate of steamed vegetables, but I decided that I would make an exception and order the steak.  I don't feel like this means that...

My 30 day challenge for August was to avoid watching any television or movies, and I finished about a week ago.  This challenge was tough, primarily since my girlfriend Stephanie (who I live with) was not under the same restriction.  As a result I ended up catching a few minutes of TV and movies here and there, but I did manage to avoid watching a complete show or movie for the entire month.  Also as a clarification, I exempted things like TED talks, screencasts, and other educational videos from this challenge.  The focus was really to avoid "junk food" entertainment that doesn't provide any lasting value. Surprises Two things surprised me about this challenge.  The first was how hard it was to go completely cold turkey.  In addition to the temptation at home, many of the bars and restaurants I went to in August (obviously) had TVs.  I also spent some time in airports, where TVs are never far away.  If you truly wanted to avoid even looking ...

Last weekend was the 2nd annual Northeast PHP conference in Boston.  I gave two talks, " Practical Responsive Web Design " ( slides ) and " Scaling PHP to 40 Million Uniques " ( slides ).  I had a lot of fun at the conference, and met some great people.  I didn't get to attend as many talks as I would have liked, since I spent some of the sessions preparing for my own, but there were a couple that I really enjoyed: