Article Firegento Hackathon Mainz 2020
This weekend I attended the Firegento Hackathon at Netz98 in Mainz. Due to the storm I had to leave early and skip presentation of my project, so I want to post a short summary of my work here on the blog.
I want to thank everyone from the Firegento organizer team, the hosts and sponsors. The event was really great and I was happy to get to know new people from the community.
I proposed a project to work on Magento 2 Performance and Profiling and we started working on it on and off with a group of 6-7 people, which is quite an awesome crowd!
The biggest achievement was that we could introduce PHP profiling to a few people that have never used Profilers before. After a general overview on how different profiling approaches work we looked at Tideways and Xdebug as examples. It was really awesome to see the reaction of what is actually possible with PHP and that its possible to gather this data.
We looked at some data from production shops with performance problems on the category page with a lot of N+1 Product loads and Andreas explained how they refactored this bottleneck away.
With input from several people we poked into Magento 2 (demo shop) and found two things that seem worth investigating more:
The Redis cache implementation could use a more efficient implementation for the app/config cache, where items are quite static over time. We saw 80-100ms of Redis calls for these caches across different shops (not only demo) that could be cut down by a more specialized cache implementation.
I attempted a prototype working on this but relaized it needs probably 2-3 days of concentrated work to get a prototype working.
One thing that Symfony + Doctrine benefit from is caches that write and execute PHP files so that Opcache can make use of interned strings, packed and immutable arrays internally.
There is a ProductViewCounter UI block that renders JSON into the output of each page. This widget is used for the feature to show the last viewed/compared products and also is responsible for the view counter in the backend. This features are often not used, but the output of this UI block is still rendered into every page anyways.
The serialization takes about 60-80ms, so there is potential here for a performance gain if there was a setting to disable this feature completly.
While working with Magneto 2 shops in Tideways, we realized there are a lot of small optimization that we can do to the callgraph profiler. There is room to add more specialized instrumentation and improve Magento 2 results. With the way Magento 2 uses interceptors (AOP) the profiling call stacks are sometimes really hard to understand, so I have written down around 10 improvement ideas we can add to the Profiler. Expect the results to go into Tideways over the next weeks and months.
This affects things like how Closures are rendered, or skipping them in the callgraph. And for a lot of calls in Magento, the actual function name should be augmented with more information, or changed to a different name to make it easier to grasp without knowing Magneto2 interceptor magic details.