Systematic Holistic Speed

Slides as presented at WordCamp Toronto, 2015

We all have created the odd WordPress site that has turned out to be fast but how do we do this each and every time?

In this talk I explore some of the techniques and choices that will make your site feel fast and also talk about how to automate / streamline your development process so that you can do this each and every time, no matter how rushed you are.

Learning Outcomes:

  • Understand what slows code down.
  • Realise how an SQL calls slow the site.
  • Understand that perceived speed can be more important than real speed.
  • Learn how to automate deployment.
  • Discover that it’s the small items that count.
  • Know what caching is, know how cache works in WordPress.
  • Understand the problems that caching causes and how to work around them.

Fitt’s law

I discovered Fitt’s law back in 2011. It states that:

The farther you are and the smaller the target, the longer it takes to move the cursor and point at said target.

Tom Stafford said it best:

“Although the basic message is obvious (big things are easier to select) it is the precise mathematical characterization that is exciting, and that this characterization includes a logarithmic function – which means that the shape of the relationship between size and reaction time is curved so that small increases in size for small objects make it much easier to select them (whereas small increases in size for big objects don’t make that much difference). And the same applies for changes in target distance.”

Size and selection times: Fitts’s Law


or in maths speak    MT = a + b log2(2A/W)

I first came across this rule in the this post, The Opposite of Fitts’ Law by Jeff Atwood:

Unintended ejection seat lever consequences
Unintended ejection seat lever consequences

Jeff talks about not putting the the “Delete Forever” button too close to the “Save” button . . . just like you wouldn’t want to put the ejector seat switch next to the radio!

Here’s another good article on Fitts’s Law: Vizualizing Fitt’s Law