JVM memory allocation for jlaunch process Testdrive N4S on Linux

[Former Member]

Hi all,

i am little confused about the memory allocation for the dispatcher and server0 jlaunch process.

In ConfigTool you can see that the heap memory size for the dispatcher is 203 MB and for the server0 1024MB.

If I do a 'top | grep jlaunch', it shows me other values...

dispatcher 515m 326m 66m

server0 1532m 1.1g 12m

I do not understand why?

Kind regards,

[nelis · Accepted solution]

If I'm not mistaken those memory sizes include virtual memory.

Try:

ps -p <pid> -o pid,vsz,rss

....where "vsz" will give you the virtual memory size and "rss" will give you the non-swapped physical memory in kilobytes.

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Nelis

[Former Member · Accepted solution]

ps -p 3173 -o pid,vsz,rss DISPATCHER

=> PID 3173 VSZ 521128 RSS 335008

ps -p 3174 -o pid,vsz,rss SERVER0

=> PID 3174 VSZ 1493048 RSS 1202852

[former_member432219]

Just a quick note from a OS independent perspective: One should remember that the max heap size is just one fraction of the memory the VM will use, there is also the permanent generation (assuming a hotspot model VM), a variable amount of memory will be used depending on the number of java threads created and also memory for native thread allocation.

From a heap and perm size perspective, to see exactly how much of the memory that the VM has reserved from the machine is actually being used, you need to examine the garbage collector output or use java monitoring software like Wily

[Former Member]

Hi Patrick,

is there a formula how we can compute the memory allocation?

Thanks and best regards,

[nelis]

You could always use the SAP Netweaver Administrator to monitor Java memory consumption. Have you tried this ?

http://<hostname>:<port>/nwa

<port> is 5<sys-no>00 ...probably 50000 on Testdrive.

Otherwise using 'ps' as above should be accurate enough to give you an idea from an OS point of view.

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Nelis