Performance, Profilers and APMs

Hey friends! Welcome to the fastest, most performant SymfonyCasts tutorial of all time, on Blackfire. The end. What? We should say a bit more?

Uh, Blackfire is all about having fun while you discover ways to make your site absurdly fast. We're going to see big graphs, numbers, statistics, animated gifs, and watch all those numbers decrease as we hunt down and eliminate performance bottlenecks. This stuff is just fun. And who doesn't want a faster site?

But... ok... just "being fun" probably isn't a good enough reason to use Blackfire. If you're trying to "sell" using a tool to your team... or management, the real reason is profit. Performance is money. Heck, Google even has a page that will measure the speed of your site and tell you how much revenue you can gain by de creasing the rendering time of your site by various amounts.

On the flip side, I'm sure you've heard the famous saying:

Premature optimization is the root of all evil

I thought it was Nickelback. If that's true... doesn't a having a cool profiling tool like Blackfire make you think more about prematurely optimizing? Actually, it's the opposite: it let's us focus on creating features and then noticing performance problems if there are any.

Performance: Server + Network + Rendering

By the way, your site's performance is really three things put together. First, the time it takes your server to build the page. Second, the time it takes to transmit that data over the network. And third, the time it takes for the browser to display stuff - the frontend. You should focus on all of these, but the main parts are the server and frontend. Your browser has tools to understand and optimize your frontend. Blackfire helps optimize your backend.

Application Performance Monitoring (APM) Versus Blackfire

But it's not the only way to monitor performance on your server. The most well-known way is by using an "application performance monitoring tool" - or APM... which is an acronym I had to look up about 10 times before I could remember what it meant! An APM is something that runs on your servers all the time, collecting information about load times, slow queries, slow functions, errors and more. The most famous one is probably NewRelic, though Blackfire is planning to release their own sometime soon.

The great thing about an APM is that you can see data from every request on your production servers. The bad part is that, because an APM is always running, it needs to collect data without slowing down the page. If it tries to collect too much, it would become the performance bottleneck!

Blackfire is a profiler. The big difference is that, instead of running on every single request that our users make... and needing to stay very lightweight, Blackfire only profiles a page when you tell it to. It then makes its own request to the page and collects an incredible amount of extremely detailed information. This process totally slows down that page load... which is fine, because there's not a real user waiting for it to return.

The point is: use an APM and a profiler. The APM will give you a constant stream of information from production. The profiler will give you the deep information you need when debugging performance on specific pages.

Project Setup

Ok, enough chat! Let's do this! To remove any bottlenecks and maximize your learning performance, you should totally code along with me. Download the course code from this page. When you unzip it, you'll find a start/ directory with the same code that you see here. Follow the README.md file for all the setup details. This is a Symfony project - but that won't matter much: we'll mostly focus on understanding and getting the most out of Blackfire.

The last setup step in the README will be to open a terminal, move into the project, use the Symfony binary to start a local web server by typing:

symfony serve

Ok, let's see the site! Find your browser and head to https://localhost:8000. Now you understand how important this project is. The world has been looking for Big Foot, or "Sasquatch", for years. Thanks to the Big-Foot fanatic community on our site - "Sasquatch Sightings" - we're closer than ever. In our case, better performance doesn't mean more profit, it means, more big foot.

Do... I know where the performance problems are? Nope. No idea. Honestly, I was too focused on getting this site to production to obsess over performance. And... I feel great about that! We'll use Blackfire to find the bottlenecks - if any - and Sasquash them!

Next, let's get Blackfire installed on my local machine and start profiling this local website. And yes, you can use Blackfire on production - which is awesome - and something we'll do later in the tutorial.