Since the announcement of the stable release of PHP 7.0.0 on December 3rd, I’ve been excited to see what the performance gains would be in a live production environment. I know that there are a lot of PHP skeptics, but there is a reason that they jumped from PHP 5 to PHP 7. This upgrade represents a big move forward in PHP code efficiency. As I consider myself somewhat of a data scientist, I wanted to write up my experience in such a way that anyone could go out and duplicate the results that I got.
At ZipBooks, we have one server that runs a Laravel-based accounting application and another server that runs a WordPress website. Our PHP upgrade on our Laravel app is yet to be completed but I have finished the upgrade for the server running Wordpress.
We have Wordpress 4.4 running on a single-core Digital Ocean server. There is nothing fancy about it. We use Nginx, PHP, and vanilla MySQL. I used New Relic to generate the graphs and Apache Bench to run some basic stress tests.
I upgrade PHP on the production server to hold as many variables constant as I could. I was most interested in what the change in requests per second would be at 100% CPU load.
Stress Testing PHP 5
I hadn’t yet set up any kind of server monitoring on our Wordpress server so I took this opportunity to set that up so I could make some nice graphs to look at. Then I installed Apache Bench and ran a couple stress tests to see what it would take to push our CPU utilization to 100%. I ended up sending 10,000 requests with 100 concurrent connections. I want to make sure that I had a big enough sample to get a meaningful throughput metric.
Here is the command I used:
sudo ab -n 10000 -c 100 https://zipbooks.com/
Here are the results:
You can see that I did a good job of stressing our poor single core server. The main metric I am going to compare is requests/second.
The little bump before was me just testing out Apache Bench to see what a baseline test would do in terms of resource demand.
PHP 7 Upgrade
I wouldn’t consider myself a server management wizard, but even for me the upgrade was extremely straight-forward. I used the instructions in the comments here.
How to add a Personal Package Archive (PPA)
Add ‘add-apt-repository’ if you don’t already have it:
$ apt-get install python-software-properties
Add PHP 7 package from Ondřej Surý’s website.
$ add-apt-repository ppa:ondrej/php-7.0
Backup any config files that you made custom changes to because you about to over write them.
The next command is going to update your package lists, remove PHP 5 and its dependencies and install PHP 7.
$ apt-get update && apt-get purge php5-fpm && apt-get --purge autoremove && apt-get install php7.0-fpm php7.0-mysql
In my case, I had to go into my Nginx configuration file and change where is was looking for the php socket. I had a little issue there because my php5-fpm socket was in a different folder.
Restart PHP and Nginx.
Stress Testing PHP 7
I liked the approach of stress testing the same server before and after the upgrade because it eliminates a lot of potential unmeasurable variables that could affect a benchmark test. So I have the same server, the same programs, and the same benchmark test. The only thing that has changed in the version of PHP that I am testing.
Here are the results:
Looks like our Wordpress website went from being able to handle 14 requests / second to 46 requests / second. That is a 228% gain in throughput. It cut the CPU load by 50%.
Below is a map of CPU usage over time during the two tests.
I am working on a free accounting software program that is great for tracking expenses and your time as a contractor. You can set people up on recurring billing and process payments via cc. It is built on Laravel and once we upgrade to PHP 7 it will run snappier than ever.