[olug] PHP-FPM, and text/stream Web pages, and memory utilization

[Lou Duchez]

So I'm working on a Web site where users will maintain a persistent 
connection to receive events.  It's in PHP, the server is using PHP-FPM 
and Apache.  Each persistent connection requires a process to send 
events to that user.

The question is, how can I measure the memory utilization of each 
instance of the process for sending events?  I *think* what I'm really 
interested in is the USS (Unique Set Size), not the RSS (Resident Set 
Size), which will essentially give me the unique memory usage plus the 
memory used by shared libraries.  Do I have the concept right?

I'm using smem to investigate this; good tool for the job, or ... ?