see how much virtual memory is assigned to a process

rmcateer · 03-01-2015, 04:48 AM

I have written a script which assigns virtual or "simulated" memory to a process that I have created. What I want to know is, how can I then list how much memory the process has? I want it to return "process has x mbs" or "process has currently no assigned memory."

How can I do this? I have included snippets of the code as it is too long to do so for pasting in here.

Code:

1)
	read -p "Enter Memory Value [MB]" p 
	$script/simulate assignmem oxygen $p
	sleep 5
	;;

function assign_mem()
{ 
stop_kill $1
	ulimit -m $2 
"$script_folder"/"$1">/dev/null&
echo "Process $1 Assigned $2MB Memory"
}

NevemTeve · 03-01-2015, 07:11 AM

Perhaps you could store the current amount in a variable.

rmcateer · 03-01-2015, 07:29 AM

what would the syntax for that be?

NevemTeve · 03-01-2015, 07:52 AM

Code:

$ MEM=100
$ ADD=4
$ ((MEM += ADD))
$ echo $MEM
104

sundialsvcs · 03-01-2015, 09:28 AM

Typically, if you want to find an accurate count of "how much memory a process has allocated or is using," you attach some form of instrumentation (or, use a library with instrumentation) to the malloc() and free() calls, or perhaps to some higher-level portion of the program which manages "interesting-to-you" data structures.

External measures of memory-use are only approximations. They generally can only see the "great big slabs of memory" (note: not using the Kernel term here ...) which the operating system hands to the program periodically for it to subdivide. They can't see how much of this the program considers to be "in use," nor what the program's using it for: only the program itself knows. Likewise, external agents can't readily see when a slab of memory is no longer being used for anything at all. Operating systems are designed to be "lazy," doing no overhead-work unless obliged to do so due to the presence of some external pressure. Thus, measurements taken on typical memory-glutted developer machines (which rarely if ever experience any sort of resource-pressure) are usually serious over-statements.

rmcateer · 03-01-2015, 09:53 AM

I have been trying to get it to read the memory that I have given it, which isn't real memory, but merely a simulation. When I put in this code, it just returns "display memory mbs." I want it to display the memory i assigned it with a previous function(if any) and i know it should be simple, but I am missing something-what is it? This is my code attempt:

Code:

function display_memory()
{
"$script_folder"/"$1">/dev/null&
echo $2MB
echo "Process $1 currently assigned $2MB Memory"
}

and from the menu

Code:

1)
	read -p "display Memory Value [MB]" p 
	$script/simulate displaymemory oxygen $p
	sleep 5
	;;