December is a perfect time to recap, to summarize what happened through the year and get ready for the next. In the performance engineering world, December is when Stojan Stefanov hosts his particular performance summary of the ending year by posting each day one article from well-known experts in the matter. The quality of the posts and the daily frequency makes you expect what’s going on tomorrow. What is better than taking longer breaks during your daily routine and draw upon low workload day to read a little bit more than usual? In case you didn’t know about the site, or if perhaps you are too much in a hurry starting up the new year, here is a short summary of my preferred articles from last 2014 Performance Calendar.

Automation - Webpagetest integration

My 3 days of Automation
Parashuram Narasimhan introduces a new automation tool set that allows you to execute test suites, gather performance data, store them in a database and visualize them in neat graphics. The article is very succinct and it contains a lot of useful links to the original tools, and also to other blog posts on performance tooling.
If you are like me, doing things twice by hand is already too much. Measuring a website’s performance using Webpagetest involves a good amount of tedious small actions. Andy Davies has developed a Google Docs Spreadsheet that cuts back the excess of boring procedures, and leaves everything ready for the Google Docs charts to come in and visualize the results directly.
Peter Hedenskog’s has been around for a while now. It combines several open source tools to analyze, compare and graph performance data from a website, allowing to integrate performance measurement in a continuous integration flow. It is being improved constantly, and with version 3.0 it allows you to include Webpagetest measurements in its already extensive breadth of data. The article is an introduction to this particular new feature, and is an excellent reason to try out the tool if you haven’t already done so.

W3C Performance API Maturity status

My 2 days of What’s coming up
HTTP 2.0 is coming at its own pace, but browser support keeps increasing, and some time in the near future it will be the standard in use. This article by Iliyan Peychev is an excellent introduction to the main features of the protocol and displays  some techniques that you could already be leveraging now. It also points out other techniques (you can call some them hacks) that we are using now but that hopefully we will be able to discard when 2.0 is widely implemented.
In the excellent article, Barbara Bermes makes a summary of the current state of the W3C APIs related to performance. The APIs are described, grouped by maturity state and by browser support, and reference to their original sources or related articles are included. Get to know which APIs you can use now, and which ones will be globally available in the near future but you can already experiment with a particular browser. This material will be included in her promising new book “Lean Websites”.

Webpagetest filmstrips

My 2 days of Performance culture
The message that performance is good for the business has to be transmitted successfully to the business stakeholders. If you have this need, Lara Hogan helps you by giving undeniable arguments and solid data foundation. Finding correlation between performance metrics and whatever numbers the upper management cares about is your objective. Plus, she makes you write down on your to-do list “read the new book Designing for Performance”, as the article is an excerpt from the book.
This article by Alex Podelko puts performance into its right perspective. Front end performance is not the only way to look at how to make web pages faster. From its historical origins many decades ago, web performance can be looked at from many angles. Load, scalability, data visualization and even human perception are also in the game. By reading this article you will have a richer and broader view into performance engineering.

MozJPEG high contrast image tuning

My 3 days of Images
Tammy Everts speaks regularly about the benefits of performance optimization. Her frequent readers like me already have a mindset so that when we see an image in a website we think right away: it should be shrunk. This time she focuses on how making images bigger also has positive impact on the user experience from other perspectives, so there is a strong need for optimization of (even large) images by choosing the right format and fine tuning their quality and placement. Her resulting checklist is something to keep in handy when the time comes that you need to optimize a website.
Speaking of image optimization, Tobias Baldauf introduces a technique that combines several tools to compress JPG images to different quality levels and choose the one with the lesser quality (and hence lesser size)  that doesn’t differ too much from the original. The article sheds some light on the inner details of the JPG format, and gives you an opportunity to improve how you leverage this format in your website with the least impact on performance.
Kornel Lesiński introduces the features of MozJPEG, a JPEG optimization library that offers several improvements over existing libraries regarding compression, quality on high contrast images, and color reproduction in high resolution images. The article also points out some ways you can use the library. An interesting set of comments also reveal how the image codification algorithms are a very sensitive topic.

Duplicate scripts behaviour by browser and load technique

My 3 days with More tools and techniques
Including a script in a webpage is so easy that you can do it more that once without notice. Is that real or only a feeling? Steve Souders takes a look at the HTTP Archive to fond out. Even more: what is the actual impact of including a script more than once? Will it be downloaded multiple times? Executed multiple times? The answer: It depends on how you load it, and it depends on the browser. The pattern of loading a script only after checking it is not already loaded is introduced in the article.
If you user Webpagetest regularly (and you should), you probably have thought about setting up your private instance and be able to test internal servers, or use the API without restrictions, or any other of its features, but perhaps you were turned down by the requirements. With this article, Pat Meenan introduces the easiest way to bring up a WPT private instance using Amazon EC2 infrastructure. Even if your productivity is an order of magnitude worse than Pat’s, this post can set you on the right track very fast!
If you went to Velocity Conference in Barcelona you already had a chance to listen to Philip Tellis talk about this. In case you didn’t, his article summarizes some alternatives you have over the time of the onload event as the main performance metric to consider. User perception of speed may be more related to when certain parts of the page are loaded, and that can differ too much from the time of the onload event. By leveraging MutationObserver you can give numbers that are closer to the real user experience. Interesting comments, too.

Performance calendar wrap-up

I have given my personal selection of articles from last year’s Performance Calendar. Absolutely not to say that the other 20 or so articles are bad, but this selection represents those that shocked me the most, and that will probably have some kind of influence on my way of working during this new and promising 2015.