Performance tuning - IBM WebSphere Portal v8

Overview

This document discusses tuning IBM WebSphere Portal v8 runing on an AIX v7.1 64-bit operating, using TDS LDAP and DB2 database.

Tuning tasks

Task	Status	Notes
Collect baseline performance metrics	Pend
Enable hardware multithreading	Pend
Heap size	Pend
Large pages	Pend
Database tuning	Pend
Directory server tuning	Pend
Web server tuning	Pend
OS and network tuning	Pend
Services tuning	Pend

Heap size tuning

For IBM WebSphere Portal v8, running on AIX 64-bit, IBM recommends generational concurrent (gencon) garbage collection, with both Initial Heap Size and Maximum Heap Size set to 3584...

Servers | Server Types | WebSphere application servers | WebSphere_Portal | Server Infrastructure: Java and Process Management | Process Definition | Java Virtual Machine

After doing any heap size tuning...

1. Verify system is spending no more than 10% of time in garbage collection.

2. Monitor the OS to make sure that paging is not occurring.

Large pages

IBM has measured a 10% throughput improvement after enabling large pages. To set...

1. Go to...
   Servers | Server Types | WebSphere application servers | WebSphere_Portal | Server Infrastructure: Java and Process Management | Process Definition | Java Virtual Machine

   ...and add -Xlp to the Generic JVM Arguments field

2. Allocate 4GB of RAM as large pages of 16MB each.

   vmo -r \
       -o lgpg_regions=288 \
       -o lgpg_size=16777216 bosboot \
       -ad /dev/ipldevice reboot \
       -q
   

3. Reboot the system

4. After reboot, enable large page support.
   vmo -p -o v_pinshm=1

   This setting persists across reboots

   For portals running under a non-root user id, grant large page usage to that user...

   chuser capabilities=CAP_BYPASS_RAC_VMM,CAP_PROPAGATE portal_user

5. Restart the Portal Server.

6. Verify large pages are being used, run...
   vmstat -l 1 5

   ...and verify alp column (active large pages) is a non-zero value.

7. In portal, change to 64K page size for text (TEXTPSIZE) and stack (STACKPSIZE), and 16MB page size for data area (DATASIZE). Go to...
   Servers | Server Types | WebSphere application servers | WebSphere_Portal | Server Infrastructure: Java and Process Management | Process Definition | Environment Entries | New

   ...and set...

   Name	LDR_CNTRL
   Value	STACKPSIZE=64k@TEXTPSIZE=64k@DATAPSIZE=16MB