PHP-FPM software Architecture

[Fleshdoom]

Hello all, does anybody have a documentation which describes PHP-FPM software architecture?
I have some doubts concerning pools and master process interactions...

In particular, I noticed that all process of certain pool write at their FD 3 when a request for that pool comes. ltrace clearly shows that only one process writes an HTML page, but strace instead shows a really confused output. I have also noticed that also PHP-FPM master process listens to the same port of the pool, I think it does this, on order to know when spawn dynamic process.

What I have found about PHP-FPM process interaction on the web, presents a too high-level description, mostly oriented to web developers. FPM official page describes only module directives. I would like instead to know how things are really working.

Regards.

[Ant P.]

It's multiple FastCGI worker processes listening on a single unix or TCP socket using accept(2), like every other web app. There's nothing complicated or magic going on.