feat: Opcache metrics

[estahn]

...

Looking at fpm_main.c it appears we cannot send PHP code directly via fcgi. PHP-PFM will need to have access to a PHP file that exposes the metrics.

Functions

• opcache_get_configuration()
• opcache_get_status()

References

• https://tideways.com/profiler/blog/fine-tune-your-opcache-configuration-to-avoid-caching-suprises
• https://www.digitalocean.com/community/questions/configure-tune-opcache-on-php7

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[guilhem]

Opcache can be mesured with #290 merged.