Performance Tuning Siebel Software on the Sun Platform

8 <strong>Performance</strong> Tweaks with No Gains
This section is most important as it sheds light on various myths of performance tuning.
Sometimes a tunable that you think is sure to result in a performance gain, does not – but
it ends up being counted as if it did. These are tunables that mostly help other
applications in a different scenario or are default settings already in effect. This section
lists out some of the tuning parameters that provided no gain when tested.
Please note: These observations are specific to the workload, architecture, software versions,
and so on used during the project at SUN ETC labs. The workload is described in Chapter 4.
The outcome of certain tuneables may vary when implemented with a different workload on
a different architecture/configuration.
Changing the mainwin address MW_GMA_VADDR=0xc0000000
Changing this to other values did not seem to make a big difference to performance. This
value is set in the siebenv file.
Solaris Kernel Parameter stksize
The default value for this is 16k, or 0x4000 on Sun4U (Ultra) architecture machines
booted in 64 bit mode (which is always the default). Increasing this to 24k, 0x6000 by the
below settings in /etc/system file did not provide any gains in performance during the
tests.
set rpcmod:svc_default_stksize=0x6000
set lwp_default_stksize=0x6000
<strong>Siebel</strong> Server Parameters
1. Recycle Factor. Enabling this did not provide any performance gains. Default is
disabled.
2. SISSPERSISSCONN. This is the parameter that changes the multiplexing ratio
between <strong>Siebel</strong> server and web server; its default value is 20. Varying this value
did not result in any performance gains for the specific modules tested in this
project with the PSPP standard workload (defined in Chapter 4).
Resonate: Cache size -- RES_PERSIST_BLOCK_SIZE
This is an environment variable which is set inside the resonate startup script. This
was changed to as high as 240Kbytes and there was no difference in behavior.
Sun Java System Web Server maxprocs
This parameter, when changed from the default of 1, starts up more than one ns-httpd
(web server process). No gain was measured with a value greater than 1. It was better to
use a new web server instance.
Database Connection Pooling with <strong>Siebel</strong> Server Components
Enabling this for the server component batch workload caused performance to degrade
such that server processes could not start. Some of the server component modules
connect to the database using ODBC, which does not support connection pooling.
<strong>Performance</strong> <strong>Tuning</strong> <strong>Siebel</strong> <strong>Software</strong> on the Sun Platform Page 56