[clue-tech] understanding Linux process memory usage?

[Jim Ockers]

Hi CLUEbies,

I wonder if anyone out there can help me understand process memory usage in Linux?
I am trying to reconcile the memory usage information from 'top' with what is
actually happening in the OS. 

It seems that something in the top numbers is out to lunch.  I am wondering about 
how to interpret the linux memory usage information as reported by ps and top.

Specifically, RSS, SIZE, SHARE, etc.  I am trying to analyze some problematic 
systems performance and nobody on the 'net seems to understand exactly how to
tell how much memory footprint a process has, exactly.  My googling has turned
up lots of questions and not very many answers.

Is it just process executable code size?  data too?  What about the stack?  What 
about X, which seems to map in video memory into the VM address space.  I know 
how big the total VM pie is, and I need to figure out exactly how big of a slice 
of that pie each process is using, especially X.

Does anyone know how to do this?  Please feel free to chime in.

Thanks,
Jim

-- 
Jim Ockers, P.Eng. (ockers at ockers.net)
Contact info: please see http://www.ockers.net/