[NTLUG:Discuss] What does RSS include?

[kbrannen@gte.net]

Neil Aggarwal wrote:
> Hello all:
> 
> Forgive my ignorance if this is a silly question.  This is definitely
> not my area of expertise.
> 
> I have Tomat running on my RedHat 9 machine with the IBM JDK.
> When I run /proc/25046/status, I get this output:
> 
...
> 
> As you can see, the RSS is about 340MB.
> 
> I have verbose output of the garbage collector for the JVM and it
> tells me that the heap is about 256 MB.  
> 
> So, there is about 80 MB of stuff in the RSS that I cannot account for.
> 
> Does anyone know what that could be?  

RSS is the Resident Set Size, which I've thought to be "everything in memory 
the program is using", which does not include what's paged/swapped out.  So in 
addition to "heap", you've also got "text" (program + s.o. libs), "data", and 
"stack" space.

> 
> Are there any utilities to help me to identify what it could be?

Not that I'm aware of, perhaps others can help here.

HTH,
Kevin