I'd like to enable opcache preloading (RFC) on my production servers in PHP 7.4.
I'm using Symfony 4 if it changes anything.
According to the blog post this appears to be trivial. Apparently Symfony since 4.4 generates a preload script which has to be set in the php.ini:
opcache.preload=/path/to/project/var/cache/prod/App_KernelProdContainer.preload.php
I did some tests in my local Docker environment and this is how it went:
PHP 7.3 without OPcache (current)
Requests per second: 8.75 [#/sec] (mean)
Time per request: 114.402 [ms] (mean)
PHP 7.4 without OPcache
Requests per second: 11.44 [#/sec] (mean)
Time per request: 87.417 [ms] (mean)
PHP 7.4 with OPcache, without preloading (Apache + modphp)
Requests per second: 30.25 [#/sec] (mean)
Time per request: 33.053 [ms]
PHP 7.4 with OPcache, without preloading (nginx + php fpm)
Requests per second: 40.00 [#/sec] (mean)
Unfortunately I was not able to enable the preloading :( I encountered following errors (in both Apache+Mod and Nginx+FPM):
double free or corruption (!prev)
child pid 17 exit signal Aborted (6), possible coredump (…)
This feature looks like a WIP though. I'm going to revalidate this answer when I'm able to use this preloading thing. In overall I'm quite impressed, +30% performance just by upgrading from PHP 7.3 to 7.4.