How to do a WordPress Plugin Speed Test

Plug-ins are one of the most attractive aspects of WordPress. No other CMS has the sheer number and variety of WordPress customizations. However, they come with a price – an increase in the load times of your site. To say that you won’t install plug-ins because you want your site to load fast is throwing the baby out with the bathwater. As with many other aspects of web hosting, it’s all about trade-offs and balance. However, to do this you need data. You need to know exactly how much a particular plug-in is impacting the load time of your site.

Without this, you’re left with nothing but guesswork. Luckily, we have plug-ins that monitor the load impacts of other plug-ins! Let’s take a look at one of the most popular tools for the job – P3 (Plugin Performance Profiler).

Analyzing Plugin Load Time

After downloading and installing the plug-in, head over to the “Tools” menu on the left-hand side of the WordPress administration dashboard and click “P3 Plugin Profiler”. This will take you to the main plug-in area where you can define and run your tests. The easiest way to get started is to simply click the “Start Scan” button with the default settings:

This will lead your site through a variety of tests consisting of clicking random links and measuring the page load statistics for each.

Depending on the load time of your site, this may take a few minutes. You see a progress bar as shown above indicating how much time is left. When all the tests are complete, the P3 Plug-In Performance Profiler will display a pie chart showing the load times of individual plug-ins.

In the test example above, the first thing we note is a huge chunk being taken up by the Jetpack for WordPress plug-in. I’ve written before about the sheer utility of Jetpack and the number of functions it takes upon itself. By itself, this might be sufficient to explain the overwhelming the large share of the load time. However when we scroll down, we see the following explanation:

When the P3 Plug-In Profiler performs its tests, it uses your current session as a logged in user. We know that several plug-ins perform additional actions for non-anonymous users. For example, caching systems will often serve uncached versions of pages if you’re logged in. Similarly, plug-ins like Jetpack perform a variety of functions for members such as page usage statistics on every load.

In fact, if you click the “More Info” link in the text box shown above, it will specify as much. So as far as Jetpack is concerned, it helps to keep this little detail in mind before passing judgment on its impact on page load speeds.

Theme Load Times

One additional benefit of the P3 plug-in is that it allows you to compare three separate systems at work within WordPress – the core functionality, the theme load time, and the plug-in load time. There are many ways of viewing the data provided by P3, and one of them is the “Simple Timeline” tab. When you click it, you get proportional representations of these three sections:

You can see that the theme load time makes up most of the page load speed. This is important because without it, you might be tempted into needlessly reducing the number of plug-ins you have. But if they themselves comprise only a small portion of the total load time of the site, you might think it worthwhile to focus your efforts elsewhere where you get the most bang for the buck.

Overall, the P3 plug-in won’t tell you what to do or which plug-ins to disable. Rather, it will give you all the data you require to make such a decision. Managing WordPress performance is a balancing act, and getting accurate data is the first step.