Performance drops after some time, PHP7-FPM + Docker

Hello, I am seeing a strange performance drop on our production servers in the PHP components. It happens usually after 1-3 uptime days, the response time suddenly doubles. I already investigated to try to isolate any strange request, but found nothing. We are having 2k to 4k RPM, the stack is PHP-FPM 7.0.X (currently 12, I just updated) into Docker containers, images are based on the official PHP-FPM Docker image. The usual response time is ~25ms, and it surges to ~50ms after this "event". Here's a typical graph of the issue : http://i.imgur.com/3WaNBL4.png After restarting the docker containers (so the PHP-FPM processes), it just works fine again. I don't really know how to investigate further. If you have any pointers on how to help figuring out what's wrong, I'd love to try. Thanks, Regards, Jérémie -- Jérémie BORDIER