Symfony2 Slow Initialization Time

Question

I have Symfony2 running on an Ubuntu Server 12.04 (64-bit) VM (VirtualBox). The host is a MacBook pro. For some reason I am getting really long request times in development mode (app_dev.php). I know its slower in dev mode, but I'm talking 5-7 seconds per request (sometimes even slower). On my Mac I get request times of 200ms or so in development mode.

After looking at my timeline in the Symfony2 profiler, I noticed that ~95% of the request time is "initialization time". What is this? What are some reasons it could be so slow?

This issue only applies to Symfony2 in dev mode, not any other sites I'm running on the VM, and not even to Symfony2 in production mode.

I saw this (http://stackoverflow.com/questions/11162429/whats-included-in-the-initialization-time-in-the-symfony2-web-profiler), but it doesn't seem to answer my questions.

Answer 1

I had 5-30 sec responses from Symfony2 by default. Now it's ~500ms in dev environment.

Then I modified the following things in php.ini:

• set realpath_cache_size = 4M (or more)
• disabled XDebug completely (test with phpinfo)
• realpath_cache_ttl=7200
• enabled and set OPcache (or APC) correctly
• restarted Apache in order to have php.ini reloaded

And voilá, responses went under 2 secs in dev mode! Hope it helps.

Before: 6779 ms

After: 1587 ms

Symfony2 reads classes from thousands of files and that's a slow process. When using a small PHP realpath cache, file paths need to be resolved one by one every time a new request is made in the dev environment if they are not in PHP's realpath cache. The realpath cache is too small by default for Symfony2. In prod this is not a problem of course.

Cache metadata:

Caching the metadata (e.g. mappings) is also very important for further performance boost:

doctrine:
    orm:
        entity_managers:
            default:
                metadata_cache_driver: apc
                query_cache_driver: apc
                result_cache_driver: apc

You need to enable APCu for this. It's APC without bytecode cache, as OPCache already does opcode caching. OPCache is built in since PHP 5.5.

---- After: 467 ms ----

(in prod environment the same response is ~80 ms)

Please note, this is project uses 30+ bundles and has tens of thousands of lines of code, almost hundred own services, so 0.5s is quite good on a local Windows environment using just a few simple optimizations.

Answer 2

I figured out the cause of the problem (and its not Symfony2). For some reason on the ubuntu VM, the modification times on certain files are incorrect (ie in the future, etc). When symfony2 checks these times using filemtime() against its registry, it determines that the cache is not longer fresh and it rebuilds the whole thing. I haven't been able to figure out why it is doing that yet.