**UPDATE 1:**

After doing an strace on the server, I have discovered that the mmap's process is taking 90% of this processing time. I've discoverd that 1 of the pages is taking a minute to load. 

So I found this link:
[PHP script keeps doing mmap/munmap](https://stackoverflow.com/questions/3021799/php-script-keeps-doing-mmap-munmap)

It possibly shows the same problem. However, I don't understand what the anwer means by correctly disabling the php error handlers?

**ORIGINAL QUESTION:**

How do I check for bottle necks on my web server when loading a specific web page which is being served by my server?

For some reason, a couple of pages on my site have become very slow, and I am not sure where the slowness is happening.

Screenshot from Chrome Dev Tools:

[Click here to enlarge](https://i.stack.imgur.com/wMpLV.png):
![enter image description here](https://i.stack.imgur.com/wMpLV.png)

So basically, I need to find out what is taking this section to long to load? Client Side web tools can't seem to break this down?