NonStop Server for Java Programmer's Reference (NSJ 4.2+)

TACL> vproc $SYSTEM.sysnn.ZCRESRL

Where sysnn is the system number.

Determining the Heap Setting

You should set the Java heap to a value appropriate for your application. For most application-server

environments, the heap size is set high to optimize performance. This size can be more than 256 MB (after QIO

has been moved to KSEG2).

To study the frequency and length of the JVM Garbage Collection operation, use the -verbose:gc option in the

JVM arguments. Then use this data to tune the heap usage of the JVM based on your application requirements.

Note: The JVM allocates the maximum required heap for the JVM usage at startup, so the swap space

considerations for the JVM process are the maximum Java heap space specified in addition to other

JVM memory requirements and the memory requirements for all native components.

To identify the swap usage of a process or the swap requirements for a CPU, use the NSKCOM utility. For

example, to identify the swap usage of all the processes or a particular process, enter the following commands at

the OSS prompt. Sample NSKCOM output follows the command line.

$ gtacl p nskcom

NSKCOM - T5838G05 BASE (22JUL02) - Nov 5 2002

$SYSTEM.SYSTEM.ZSYSCFG

KMS.SWAPFILE = 0 $DATA03.SWAP.CPU0A STOP

KMS.SWAPFILE = 0 $DATA03.SWAP.CPU0B STOP

KMS.SWAPFILE = 5 $SWAP45.SWAP4.CPU05

NSK-status swap-usage 1,423 ,detail

SYSTEM : \GOBLIN LOGTIME : March 19, 2004 02:50:29

TYPE : (E=Extensible S=Shared O=Owner)

(CPU Page size is 16384 Bytes)

_____________________________________________________________________________

Process Pri User-ID Program File Name

$JSV1 1,423 155 103,43 $DATA11.ZYQ0000T.Z00001VH

KMSF-BACKED SEGMENTS: (Process Space Guarantee = 1904KB)

-----------------------------------------------------------------------------

SEG-ID TYPE SIZE RESERVATION

KBYTE PAGES KBYTE

-----------------------------------------------------------------------------

2101 8B 1 16

2100 8B 1 16

Heap+Global+SRL+Stack 330MB 21187 331MB

-----------------------------------------------------------------------------

TOTAL 21187 331MB

FILE-BACKED SEGMENTS: None